book of abstracts - spbu.ru of abstracts saint petersburg ... george kuranov konstantin mikhelson...

25th European Symposium on Applied Thermodynamics

June 24-27, 2011

Saint Petersburg, Russia

ESAT 2011

BOOK OF ABSTRACTS

Saint Petersburg State University Institute of Macromolecular Compounds, Russian Academy of Sciences

The Mendeleev Russian Chemical Society

CD ROM Included

Saint Petersburg, Russia II ESAT 2011

SPONSORS

IUPAC

ESAT 2011 25th European Symposium on Applied Thermodynamics Editors: Igor Gotlib, Alexey Victorov and Natalia Smirnova

ISBN: 5-85263-061-6

Saint Petersburg, Russia III ESAT 2011

SPONSORS

Building on two centuries' experience, Taylor & Francis has grown rapidly over the last two decades to become a leading international academic publisher. Operating from a network of 20 global offices, including New York, Philadelphia, Oxford, Melbourne, Stockholm, Beijing, New Delhi, Johannesburg, Singapore and Tokyo, the Taylor & Francis Group publishes more than 1,500 journals and around 1,800 new books each year, with a books backlist in excess of 20,000 specialist titles. Molecular Physics is one of our top Physical Science titles. It is a well-established international journal publishing original high quality papers in chemical physics and physical chemistry. The journal covers all experimental and theoretical aspects of molecular science, from electronic structure, molecular dynamics, spectroscopy and reaction kinetics to condensed matter, surface science, and statistical mechanics of simple and complex fluids. Contributions include full papers, preliminary communications, research notes and invited topical review articles.

http://www.netzsch-thermal-analysis.com

Saint Petersburg, Russia IV ESAT 2011

CONTENTS Committees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V History of ESAT Meetings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VI Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VII Conference Timetable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IX Scientific Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XV Abstracts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Oral Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Poster Session I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 Poster Session II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293 Author Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425 List of Participants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435

Saint Petersburg, Russia V ESAT 2011

International Steering Committee Honorary Members: Jakob de Swaan Arons, Delft (The Netherlands) Dimitrios P. Tassios, Athens (Greece) Chairperson: Evelyne Neau, Marseille (France) Members: Karel Aim, Praha (Czech Republic) Ralf Dohrn, Leverkusen (Germany) Urszula Domańska-Żelazna, Warsaw (Poland) Jean-Noël Jaubert, Nancy (France) Georgios M. Kontogeorgis, Lyngby (Denmark) Theo W. de Loos, Delft (The Netherlands) Eugenia Macedo, Porto (Portugal) Kostis Magoulas, Athens (Greece) Alberto Arce, Santiago de Compostela (Spain) Local Organizing Committee

Natalia Smirnova (co-chair) Alexey Victorov (co-chair) Igor Prikhodko (scientific secretary) Eugenia Safonova (scientific secretary) Tatiana Filippova (scientific secretary) Anton Balaban Stanislav Burov

Galina Chernik Igor Gotlib George Kuranov Konstantin Mikhelson Vladimir Sizov Alexander Toikka Maria Toikka

International Scientific Committee

Paolo Alessi, Trieste (Italy) Alberto Arce, Santiago (Spain) Alexander Bilibin, St.Petersburg (Russia) Theo de Loos, Delft (The Netherlands) Josefa Fernández, Santiago (Spain) Amparo Galindo, London (UK) Rafiqul Gani, Lyngby (Denmark) Konstantin Gavrichev, Moscow (Russia) Jürgen Gmehling, Oldenburg (Germany) Alexei Khokhlov, Moscow (Russia)

Trevor Letcher, Stratton on the Fosse (UK) Eugenia Macedo, Porto (Portugal) Alexey Morachevsky, St. Petersburg (Russia) Eugeny Panarin, St.Petersburg (Russia) Cor J. Peters, Delft (The Netherlands) John Prausnitz, Berkeley (USA) Dominique Richon, Fontainebleau (France) Anatoly Rusanov, St.Petersburg (Russia) Yury Tretiakov, Moscow (Russia) Ivan Wichterle, Prague (Czech Republic)

Saint Petersburg, Russia VI ESAT 2011

HISTORY OF ESAT MEETINGS

Helmut Knapp (1923–2009) was the founder of ESAT symposia

ESAT Year Organizer(s) Place Country

1st 1974 Tech. Univ. Berlin Berlin (West) Germany

2nd 1976 Tech. Univ. Berlin Berlin (West) Germany

3nd 1978 Tech. Univ. Denmark Lyngby Denmark

4th 1979 Shell, Amsterdam Amsterdam The Netherlands

5th 1980 Linde AG, München Sachrang Germany

6th 1982 Institut Francais du Petrole Rueil-Malmaison France

7th 1983 Univ. Dortmund Dortmund Germany

8th 1985 Univ. Trieste Trieste Italy

9th 1987 Norsk Hydro, Porsgrunn Bergen Norway

10th 1988 Univ. Porto Ofir Portugal

11th 1990 Tech. Univ. Denmark Rungsted Denmark

12th 1991 Tech. Univ. Berlin Berlin Germany

13th 1993 Univ. Marseille Marseille France

14th 1994 Nat. Tech. Univ. Athens Marathon Greece

15th 1996 ICI, Runcorn Runcorn UK

16th 1997 Univ. Metz + ENSIC-INPL, Nancy Pont-a-Mousson France

17th 1999 Univ. Porto + Univ. Aveiro Vilamoura Portugal

18th 2000 ICT, Prague + ICPF, Prague Kutna Hora Czech Republic

19th 2002 Nat. Tech. Univ. Athens Santorini Greece

20th 2003 VDI-GVC, Duesseldorf + Bayer AG, Leverkusen + Univ. Kaiserslautern Lahnstein Germany

21st 2005 Warsaw Univ. of Tech. Jurata Poland

22nd 2006 Tech. Univ. Denmark Elsinore Denmark

23rd 2008 ENSIC-INPL, Nancy Cannes France

24th 2009 ETSE, Univ. of Santiago de Compostela

Santiago de Compostela Spain

25th 2011 St.Petersburg State Univ., Russian Acad. Sci., the Mendeleev Russian Chem. Soc.

St.Petersburg Russia

Saint Petersburg, Russia VII ESAT 2011

PREFACE

It is our pleasure to thank all the participants for coming to 25th ESAT and to welcome you in St.Petersburg. It is for the first time that ESAT is taking place in Russia, and we are proud that our city has been chosen to host the conference. Establishing extensive cooperation between Russia and Europe had been the major plan of Peter the Great, the founder of St.Petersburg, who launched the new Russian capital at the sea-gate to Europe. St.Petersburg made a remarkable contribution to the Russian and International culture and science. Many familiar and dear names, including Tchaikovsky, Shostakovich, Dostoevsky, Mendeleev, Fock, and a lot more are closely related to our city. It is also a touristic place that many of you will enjoy.

ESAT-2011 takes place in the year declared the International Year of Chemistry and brings together scientists and engineers from universities, industry and research institutions of more than 40 countries in Europe, Asia, Africa, South America and North America. We hope that continuing tradition of the previous meetings, ESAT-2011 will serve as a communication medium, bridging industrial needs and practical means on the one hand, with scientific curiosity and academic expertise on the other.

Latest trends in Applied Thermodynamics are clearly seen from the contributions to ESAT-2011, including those on Phase Equilibria, Molecular Thermodynamics of Complex Fluids, Process and Product Design, Ionic Liquids, Polymers and Biochemical Systems, Storage and Capture of Greenhouse Gases. An overwhelmingly large number of submitted excellent works forced the organizers to arrange 3 parallel oral sessions which is new to ESAT symposia.

More than 20% of participants are young researches, including graduate and undergraduate students. It is a pleasure to see so many young faces among us and to announce a number of junior ESAT awards. We established a junior award dedicated to Prof. Helmut Knapp (1923-2009), the founder of ESAT symposia, for the best poster contribution. Priority is given to practice-oriented work with clear perspective of industrial application. A junior award has been established by Netzsch for advanced applications of calorimetry and thermal analysis. Student poster awards at ESAT-2011 will also be granted by the International Association of Chemical Thermodynamics (IACT). During the symposium the European Federation of Chemical Engineers, Working Party on Thermodynamic and Transport Properties, will award the prize established for the best PhD work.

The organizers of the meeting would like to thank the Russian Academy of Sciences, the Russian Foundation for Basic Research, and all our sponsors for their support of this conference. Our special thanks are to IUPAC sponsorship of ESAT-2011.

We just hope that often treacherous St.Petersburg’s weather will not prevent us from enjoying the beauty of our city and its magnificent “white nights”. On behalf of the Organizing Committee

Alexey Victorov, Natalia Smirnova

Saint Petersburg, Russia VIII ESAT 2011

Saint Petersburg, Russia IX ESAT 2011

CONFERENCE TIMETABLE

Saint Petersburg, Russia X ESAT 2011

Saint Petersburg, Russia XI ESAT 2011

FRIDAY, 24.06.2011

17.00 – 19.30 Arrivals Registration (Ceremony Hall, main building)

19.30 Welcome reception

SATURDAY, 25.06.2011 09.00 – 09.15 Opening (Ceremony Hall, main building)

Plenary session (Ceremony Hall, main building) Chair: E. Neau, A. Arce

09.15 – 09.45 G.M. Kontogeorgis (p. 5) 09.45 – 10.30 A. Galindo (p. 6) 10.30 – 11.00 A.I. Rusanov (p. 7) 11.00 – 11.30 Coffee break Session 1: Process

and Product Design (Ceremony Hall, main building) Chair: R. Dohrn, K. Magoulas

Session 2: Molecular Thermodynamic Modeling, Theory and Computer Simulation (Peter’s Hall, main building) Chair: A. Galindo, J. O’Connell

Session 3: Ionic Liquids (Chemistry Center building) Chair: C.J. Peters, A. Heintz

11.30 – 11.50 C. Coussine (p. 11) S. Pereda (p. 25) K. Paduszyński (p. 39)

11.50 – 12.10 J.F. Rodríguez (p. 13)

W.R. Smith (p. 27) P. Izák (p. 40)

12.10 – 12.30 S.I.C. Vieira (p. 16) J.P. Simonin (p. 28) U.M. Domańska-Żelazna (p. 41)

12.30 – 12.50 K. Ballerat-Busserolles (p. 18)

T.J.H. Vlugt (p. 30) N.A. Smirnova (p. 43)

12.50 – 13.10 N. Sadegh (p. 19) T. Mehling (p. 32) E. Alevizou (p. 45)

13.10 – 13.30 C.S.G.P. Queirós (p. 20)

M.A. Anisimov (p. 34) S.P. Verevkin (p. 47)

13.30 – 13.50 K. Müller (p. 22) J. Dávila (p. 35) J. Fernández (p. 49) 13.50 – 15.30 Lunch

Saint Petersburg, Russia XII ESAT 2011

Session 4: Surfactants, Polymers and Bio-Related Systems (Ceremony Hall, main building) Chair: E. Macedo, S. Enders

Session 5: Molecular Thermodynamic modeling, theory and computer simulation (Peter’s Hall, main building) Chair: K. Aim, L. Vega

Session 6: Interfacial phenomena (Chemistry Center building) Chair: A. Rusanov, M. Anisimov

15.30 – 15.50 J. Kosek (p. 53) F. Llovell (p. 67) D.V. Tatyanenko (p. 79) 15.50 – 16.10 P. Schrader (p. 55) P. Paricaud (p. 69) F. Hodaj (p. 81) 16.10 – 16.30 S. Wille (p. 57) S. Deublein (p. 71) J.K. Singh (p. 82)

16.30 – 16.50 J.P. O'Connell (p. 59)

J.R. Elliott (p. 72) M.R. Dehghani (p. 83)

16.50 – 17.10 F.L. Mota (p. 60) I. Nezbeda (p. 74) M. Horsch (p. 85) 17.10 – 17.30 S. Hempel (p. 62) S. Sazhin (p. 75) M. Kosmulski (p. 87) 17.30 – 19.30 Poster Session 1 (p. 157) 19.30 – 21.00 Dinner 21.00 – 22.30 City tour

SUNDAY, 26.06.2011

Plenary session (Ceremony Hall, main building) Chair: N. Smirnova, J.-N. Jaubert

09.00 – 09.30 L.F. Vega (p. 91) 09.30 – 10.15 I. Smirnova (p. 93) 10.15 – 10.45 M. Francisco (p. 94) 10.45 – 11.15 Coffee break

Session 7: Surfactants, Polymers and Bio-Related Systems (Ceremony Hall, main building) Chair: G. Sadowski, I. Smirnova

Session 8: Phase Equilibria and Thermophysical Data: measurement, analysis and predictive tools (Peter’s Hall, main building) Chair: M. Trusler, J. Gmehling

Session 9: Petroleum fluids (Chemistry Center building) Chair: E. Voutsas, E. Hendriks

11.15 – 11.35 V. Kocherbitov (p. 99)

E.A. Brignole (p. 113) E. Neau (p. 125)

11.35 – 11.55 M.G. De Angelis (p. 101)

T.W. De Loos (p. 115) M. Cismondi Duarte (p. 127)

11.55 – 12.15 J. Völkl (p. 103) C. Secuianu (p. 116) E. Skouras (p. 129)

Saint Petersburg, Russia XIII ESAT 2011

12.15 – 12.35 A.F. Kostko (p. 104) E.J.M. Filipe (p. 118) M. Riaz (p. 131) 12.35 – 12.55 A. Takada (p. 106) M. Chorążewski

(p. 119) J.-N. Jaubert (p. 132)

12.55 – 13.15 L. Padrela (p. 107) C.D. Muzny (p. 120) B. Rousseau (p. 134) 13.15 – 13.35 J. Cassens (p. 109) A. Hukkerikar (p. 121) D.V. Nichita (p. 136) 13.35 – 15.00 Lunch

Plenary session (Ceremony Hall, main building) Chair: G. Kontogeorgis, Th. de Loos

15.00 – 15.30 J. Gmehling (p. 141) 15.30 – 16.00 J.P.M. Trusler (p. 142) 16.00 – 18.00 Poster Session 2 (p. 293) 20.00 – 22.00 Gala Dinner

MONDAY, 27.06.2011

Plenary session (Ceremony Hall, main building) Chair: A. Victorov, U.M. Domanska-Żelazna

09.30 – 10.15 E. Hendriks (p. 147) 10.15 – 10.45 E. Voutsas (p. 149) 10.45 – 11.15 K. Saito (p. 150) 11.15 – 11.45 Coffee break 11.45 – 12.05 C.J. Peters (p. 151) 12.05 – 12.25 C.A. Nieto De Castro (p. 152) 12.25 – 12.55 A. Heintz (p. 154) 12.55 – 13.25 G. Etherington (p. 155) 13.25 – 13.40 Young Scientists Awards 13.40 – 13.50 26th ESAT Presentation 13.50 – 13.55 Closure of the 25th Symposium 13.55 – 15.30 Lunch Departure Post-Conference event

Setaram Seminar (15.30 – 17.30, Chemistry Center building)

Sectional talks: 20 min (15 min for talk + 5 min for questions)

Saint Petersburg, Russia XIV ESAT 2011

Saint Petersburg, Russia XV ESAT 2011

SCIENTIFIC PROGRAM

Saint Petersburg, Russia XVI ESAT 2011

Saint Petersburg, Russia XVII ESAT 2011

SATURDAY, 25.06.11

PLENARY SESSION Chair persons: E. Neau, A. Arce

Industrial Requirements for Thermodynamics and Transport Properties - Before and Now Hendriks E., Kontogeorgis G.M., Dohrn R., De Hemptinne J.-C., Economou I., Fele Žilnik L., Vesovic V. ..................................................................................................... 5

Invited Lecture: Phase behaviour, solubility and salting out in aqueous solution: SAFT approaches and computer simulations Galindo A...................................................................................................................... 6

Invited Lecture: Thermodynamic Fundamentals of Solid Strength Rusanov A.I. ................................................................................................................. 7

SESSION 1: Process and Product Design Chair persons: R. Dohrn, K. Magoulas

Thermodynamic modelling of thermal salt production process Coussine C., Cezac P., Serin J.-P., Contamine F., Reneaume J.-M., Dubourg K., Cambar J.................................................................................................................... 11

Development of Functional Textiles for Summer Wear Sánchez-Silva L., Rodríguez J.F., Sánchez P. .......................................................... 13

Paints with IoNanofluids as pigments for improvement of heat transfer on architectural and heat exchangers surfaces Vieira S.I.C., Ribeiro A.P.C., Lourenço M.J.V., Nieto De Castro C.A......................... 16

Thermodynamic study of systems CO2-AMINE-WATER for CO2 capture processes Ballerat-Busserolles K., Simond M., Coulier Y., Rodier L., Coxam J.-Y..................... 18

Thermodynamic modeling of sour gas cleaning process with alkanolamine Sadegh N., Kontogeorgis G.M., Stenby E.H., Thomsen K. ........................................ 19

Study of Fruit Waste Reuse as New Thermal Absorbing Materials Queirós C.S.G.P., Vieira S.I.C., Lourenço M.J.V. ...................................................... 20

Modeling of the production of hydrogen from saccharides as main ingredients of biomass Müller K., Lobanova O., Mokrushina L., Arlt W. ......................................................... 22

Saint Petersburg, Russia XVIII ESAT 2011

SESSION 2: Molecular Thermodynamic Modeling, Theory and Computer Simulation

Chair persons: A. Galindo, J. O'Connell

Thermodynamic modeling of ethanol/gasoline blends Soria T.M., Gonzalez Prieto M., Pereda S., Bottini S.B.............................................. 25

A Molecular Based Osmotic Ensemble Monte Carlo Simulation Method for Free Energy Solvation Curves and the Direct Calculation of Aqueous Electrolyte Solubility Smith W.R., Moucka F., Lisal M. ................................................................................ 27

Effect of polarization on the solubility of gases in molten salts Simonin J.P. ............................................................................................................... 28

Multicomponent Maxwell-Stefan Diffusivities at Infinite Dilution Vlugt T.J.H., Liu X., Bardow A.................................................................................... 30

Modeling of electrolyte solutions with COSMO-RS Ingram T., Gerlach T., Mehling T., Smirnova I. .......................................................... 32

Invited Lecture: Liquid Water: A State Between Two Critical Points Anisimov M.A. ............................................................................................................ 34

Solubility of K2SO4 in Supercritical Water using Monte Carlo Method Dávila J., Moncada M., Caceres J.............................................................................. 35

SESSION 3: Ionic Liquids Chair persons: C. Peters, A. Heintz

Measurements and equation-of-state modeling of liquid-liquid phase equilibria in binary systems containing a piperidinium ionic liquid Paduszyński K., Domańska-Żelazna U.M. ................................................................. 39

How ionic liquid changes properties of dense membrane in pervaporation separation process? Kacirkovák M., Randová A., Hovorka S., Schauer J., Tisma M., Izák P. ................... 40

Phase Behavior and Thermodynamic Properties of the Binary Systems Quinolinium, or Isoquinolinium-Based Ionic Liquids + Hydrocarbon, or + an Alcohol Domańska-Żelazna U.M., Zawadzki M....................................................................... 41

Imidazolium ionic liquids as amphiphilic additives in solutions Safonova E.A., Koneva A.S., Smirnova N.A. ............................................................. 43

Solubility of cinnamic acid derivatives in ionic liquids: experimental measurements and thermodynamic modeling Alevizou E., Voutsas E. .............................................................................................. 45

Treble calorimetry: an elegant access to vaporization enthalpies of ionic liquids by DSC, solution, and combustion calorimetry Verevkin S.P., Emel'yanenko V.N., Ralys R., Zaitsau Dz.H., Heintz A., Schick C. .... 47

Saint Petersburg, Russia XIX ESAT 2011

High-Pressure Densities of Ionic Liquids: Structure-Property Relations and New Measurements Regueira T., Lugo L., Fernández J............................................................................. 49

SESSION 4: Surfactants, Polymers and Bio-Related Systems Chair persons: E. Macedo, S. Enders

Sorption equilibria and diffusion dynamics in semi-crystalline polymers Kosek J., Hájová H., Pokorný R., Chmelař J., Nistor A. ............................................. 53

Phase Equilibria of Surfactant Containing Systems Schrader P., Kulaguin – Chicaroux A., Dorn U., Enders S......................................... 55

Modeling of Phase Equilibria in Microemulsion Systems Based on Partition Coefficients Wille S., Sponsel E., Mokrushina L., Arlt W. .............................................................. 57

Applications of H-D Exchange Measurements for Protein Structure, Equilibria, and Kinetics O'Connell J.P., Fernandez E.J. .................................................................................. 59

Solubility of Drug-Like Molecules in Pure, Mixed and Supercritical Solvent Systems with the CPA EoS Mota F.L., Queimada A.J., Pinho S.P., Macedo E.A. ................................................. 60

Activity Coefficients and Structure of Water in Amino-Acid Solutions Hempel S., Sadowski G. ............................................................................................ 62


Chair persons: K. Aim, L. Vega

Thermodynamic modeling of cross-association systems with the soft-SAFT EoS Llovell F., Vilaseca O., Valente E., Jung N., Vega L.F. .............................................. 67

Modeling of the dissociation conditions of salt hydrates and gas semiclathrate hydrates. Application to lithium bromide, hydrogen iodide hydrates, and mixed hydrates of gas + Tetra-n-butylammonium bromide Paricaud P., Bouchafaa W., Dalmazzone D............................................................... 69

Molecular Simulation of Aqueous Electrolyte Solutions – New Force Fields for Monovalent Anions and Cations Deublein S., Reiser S., Vrabec J., Hasse H. .............................................................. 71

Accounting for Non-classical Critical Scaling with DMD/TPT in the Long Chain Limit Elliott J.R., Ghobadi A.F. ............................................................................................ 72

A new concept for augmented van der Waals equations of state Nezbeda I., Trokhymchuk A., Melnyk R. .................................................................... 74

Saint Petersburg, Russia XX ESAT 2011

Modelling of Complex Hydrocarbon Droplet Heating and Evaporation: Hydrodynamic, Kinetic and Molecular Dynamics Approaches Sazhin S.S., Elwardany A., Gusev I.G., Xie J.-F., Cao B.-Y., Shishkova I.N., Snegirev A.Yu., Heikal M.R. ...................................................................................................... 75

SESSION 6: Interfacial Phenomena Chair persons: A. Rusanov, M. Anisimov

Grand Potential for Solids and Solid-Fluid Interfaces Tatyanenko D.V., Rusanov A.I., Shchekin A.K. ......................................................... 79

Fundamental issues of metal/ceramic interfacial reactions: thermodynamics and kinetics Hodaj F....................................................................................................................... 81

Phase transitions of water in mica and graphite pores Srivastava R., Docherty H., Singh J.K., Cummings P.T. ............................................ 82

Surface tension of atmospheric solutions. Modeling aqueous organic-inorganic mixtures Dalirian M., Dehghani M.R. ........................................................................................ 83

A new route to evaluate the curvature dependence of the surface tension of vapour-liquid interfaces by molecular simulation Horsch M., Miroshnichenko S., Vrabec J., Shchekin A.K., Müller E., Jackson G....... 85

New approach to the surface charging of metal oxides in nonaqueous solvents Kosmulski M., Próchniak P., Mączka E., Rosenholm J.B........................................... 87

SUNDAY, 26.06.11

PLENARY SESSION Chair persons: N. Smirnova, J.-N. Jaubert

Materials for carbon capture and utilization in the context of sustainable energy development Vega L.F., Builes S., López-Aranguren P., Pacciani R., Ramirez R., Domingo C. .... 91

Invited Lecture: Surfactant based separation processes: thermodynamic aspects Smirnova I. ................................................................................................................. 93

EFCE Excellence Award in Thermodynamics and Transport Properties 2011: Desulfurization of Fuel Oils by Solvent Extraction with Ionic Liquids Francisco M................................................................................................................ 94

SESSION 7: Surfactants, Polymers and Bio-Related Systems Chair persons: G. Sadowski, I. Smirnova

Enthalpy and entropy driven phase transitions in surfactant and lipid systems Kocherbitov V. ............................................................................................................ 99

Saint Petersburg, Russia XXI ESAT 2011

A multiscale method for the prediction of the volumetric and gas solubility behavior of high-Tg polymers Minelli M., Heuchel M., De Angelis M.G., Hofmann D., Sarti G.C., Doghieri F. ....... 101

Predicting thermodynamic properties of Hyperbranched Polymers Völkl J., Arlt W. ......................................................................................................... 103

Stability of polystyrene latex suspended in water at high pressure and high temperature Kostko A.F., McHugh M.A. ....................................................................................... 104

New description of structural disorder in glass based on statistical thermodynamics Takada A., Richet P., Atake T. ................................................................................. 106

Properties of pharmaceutical cocrystals generated by supercritical fluids Padrela L., Rodrigues M., Duarte T., Matos H.A., De Azevedo E.G. ....................... 107

Aqueous Solubility of Pharmaceuticals at Different pH Cassens J., Prudic A., Ruether F., Sadowski G. ...................................................... 109

SESSION 8: Phase Equilibria and Thermophysical Data: measurement, analysis and predictive tools

Chair persons: M. Trusler, J. Gmehling

Phase Equilibria for the Recovery of Monoglycerides from Fatty Esters using Near Critical CO2+Propane Mixtures Hegel P.E., Vélez A., Pereda S., Mabe J., Brignole E.A. ......................................... 113

Fluid phase behavior of trifluoromethane + phenylalkanes Bogatu C., Geana D., Poot W., De Loos T.W. ......................................................... 115

Diffusion coefficients of aqueous KCl at high pressures measured by the Taylor dispersion method Secuianu C., Maitland G.C., Trusler J.P.M............................................................... 116

Thermodynamics of Perfluoroalkylalkanes: liquid, surface and transport properties Morgado P., Filipe E.J.M., Rodrigues H., Martins L.F.G., Blas F., McCabe C. ........ 118

Thermophysical properties of Shell Normafluid over extended ranges of temperature (243-423 K) and pressure (0.1-200 MPa) Chorążewski M., Grolier J.-P.E. ............................................................................... 119

Dynamic Web-based Data Dissemination through Web Thermo Tables Kroenlein K., Muzny C.D., Diky V., Kazakov A., Chirico R.D., Magee J.W., Abdulagatov I., Frenkel M. ....................................................................................... 120

Estimation of Properties of Pure Components Using Improved Group Contribution Based and Atom Connectivity Index Based Models and Uncertainty Analysis Hukkerikar A., Sarup B., Sin G., Gani R................................................................... 121

Saint Petersburg, Russia XXII ESAT 2011

SESSION 9: Petroleum Fluids Chair persons: E. Voutsas, E. Hendriks

The NRTL-PR Equation for the Modelling of Synthetic Petroleum Fluids with Associating Compounds: Prediction of Phase Envelopes and Influence of Lumping/Delumping Procedures Neau E., Escandell J., Nicolas C.............................................................................. 125

Detection of Solid-Liquid Retrograde Melting From Computing Solid-Fluid-Fluid Equilibrium Lines Rodríguez Reartes S.B., Cismondi Duarte M., Zabaloy M.S.................................... 127

Online cricondenbar monitoring in rich gas pipelines Skouras E., Solbraa E., Christensen K.O., Løkken T.V., Aase B.Ø., Ovesen R.V., Aaserud C. ............................................................................................................... 129

Distribution of gas hydrate inhibitors in oil and gas production systems Riaz M., Kontogeorgis G.M., Stenby E.H., Yan W., Haugum T., Christensen K.O., Solbraa E., Løkken T.V. ........................................................................................... 131

Towards a group-contribution method to predict temperature-dependent binary interaction parameters (kij) whatever the cubic equation of state and the associated alpha function Jaubert J.-N., Privat R. ............................................................................................. 132

Gas mixtures solubility in polyethylene below its melting temperature. A molecular simulation study Rousseau B., Lachet V., Memari P. ......................................................................... 134

Phase Stability Analysis Using a Reduction Method Nichita D.V. .............................................................................................................. 136

PLENARY SESSION Chair persons: G. Kontogeorgis, Th. de Loos

The Universal Group Contribution Equation of State VTPR - Present Status and Potential for Process Development Gmehling J., Schmid B. ............................................................................................ 141

Fundamental Equation of State for Solid Phase I of Carbon Dioxide Trusler J.P.M. ........................................................................................................... 142

MONDAY, 27.06.11

PLENARY SESSION Chair persons: A. Victorov, U.M. Domańska-Żelazna

Invited Lecture: Predictive approach for aqueous amine acid gas loading Schrey A., Westerholt A., Fischer K., Hendriks E..................................................... 147

Saint Petersburg, Russia XXIII ESAT 2011

Invited Lecture: Phase equilibrium in natural gas mixtures Voutsas E. ................................................................................................................ 149

Invited Lecture: Restricted Dynamics of Hydrocarbon Chain in Lamellar Phase of Lipid-Water Systems Saito K., Yamamura Y.............................................................................................. 150

Van der Waals and Beyond Peters C.J. ............................................................................................................... 151

Mendeleev density studies of Ethanol + Water Mixtures. What have we learnt about the treatment of experimental results since then? Lampreia I.M.S., Lourenço M.J.V., Nieto De Castro C.A. ........................................ 152

Thermodynamic properties of ionic liquids and their mixtures Heintz A.................................................................................................................... 154

Use of high pressure flow calorimetry in the evaluation of the CO2 capture and sequestration technologies Le Parlouër P., Etherington G. ................................................................................ 155

POSTER SESSION 1

SATURDAY, 25.06.2011

PI-1. Parameter estimation for the PCP-SAFT EOS using a minimal amount of experimental data Albers K., Heilig M., Sadowski G.............................................................................. 159

PI-2. Including polarizability effects in GC-PPC-SAFT: application to alkyl-ether containing systems Auger E., Passarello J.P., Paricaud P., Tobaly P., Volle F....................................... 161

PI-3. High Temperature Vapour-Liquid Equilibria of Ethanol-Water Mixtures Cristino A.F., Rosa S.C.S., Morgado P., Galindo A., Filipe E.J.M., Palavra A.M.F., Nieto De Castro C.A................................................................................................. 163

PI-4. Predicting second-order derivative properties with a modified SAFT-CP equation of state De Villiers A.J., Schwarz C.E., Burger A.J. .............................................................. 165

PI-5. Application of Artificial Bee Colony optimization algorithm in phase behavior calculations Tahooneh A., Yazdizadeh M., Eslamimanesh A., Mohammadi A.H., Richon D....... 166

PI-6. Thermodynamic model for predicting dissociation conditions of gas hydrates in porous media Eslamimanesh A., Mohammadi A.H., Richon D. ...................................................... 167

PI-7. Thermodynamic Consistency Test of Experimental Phase Equilibrium Data: is it Really a Necessary Step? Eslamimanesh A., Mohammadi A.H., Richon D. ...................................................... 168

Saint Petersburg, Russia XXIV ESAT 2011

PI-8. Determination of Physical Properties using Group contribution Strategies: Suggestions and Modifications Gharagheizi F., Eslamimanesh A., Mohammadi A.H., Richon D. ............................ 169

PI-9. Prediction of hydrogen sH hydrate phase boundary in the presence of alkanes, alkenes, alkynes and cycloalkanes promoters Babaee S., Hashemi H., Javanmardi J., Eslamimanesh A., Mohammadi A.H......... 170

PI-10. Phase Equilibria of Semi-Clathrate Hydrates of Tetra-n-butyl ammonium bromide + Mixtures of Carbon Dioxide with methane, nitrogen, hydrogen Mohammadi A.H., Eslamimanesh A., Belandria V., Richon D. ................................ 171

PI-11. Modulation of Hydrophobicity of Surfactant Tail by Specific Salt and its Role in Self-Assembly of an Ionic Micelle Koroleva S.V., Victorov A.I. ...................................................................................... 172

PI-12. Assessment of Asphaltene Stability in Crude Oils Using New Colloidal Stability Index Likhatsky V.V., Syunyaev R.Z. ................................................................................. 174

PI-13. Kinetics and thermodynamics of asphaltene adsorption on iron Safieva J.O., Syunyaev R.Z. .................................................................................... 176

PI-14. Vapour-liquid equilibria on the carbon dioxide - aqueous solutions systems from 293 to 393 K: experiments and modeling Lucile F., Cezac P., Contamine F., Houssin-Agbomson D., Arpentinier Ph., Baudouin O............................................................................................................................... 178

PI-15. An Electrolyte CPA Equation of State for Applications in the Oil and Gas Industry Maribo-Mogensen B., Kontogeorgis G.M., Thomsen K............................................ 179

PI-16. Phase Behaviour Modelling of Chemical Reactions in Dense and Supercritical Carbon Dioxide using the Cubic-Plus-Association Equation of State Musko N.E., Kontogeorgis G.M., Grunwaldt J.-D., Tsivintzelis I. ............................. 181

PI-17. Pressure Effect on Phase Behavior of Surfactant System Sandersen S.B., Von Solms N.S., Stenby E.H......................................................... 183

PI-18. Modeling of Mixtures with Acid Gases using the CPA Equation of State Tsivintzelis I., Kontogeorgis G.M., Michelsen M., Stenby E.H. ................................ 185

PI-19. Dynamic flow method to study the CO2 loading capacity of amino acid salt solutions Lerche B.M., Stenby E.H., Thomsen K. ................................................................... 187

PI-20. Densities, excess volumes, isobaric expansivities and isothermal compressibilities of the 1-butyl-3-methylimidazolium methylsulfate + methanol system at temperatures (283.15 to 353.15) K and pressures from (0.1 to 35) MPa Matkowska D., Hofman T. ........................................................................................ 189

PI-21. Dilatational rheology of the adsorption films of complexes between globular proteins and ionic surfactants Mikhailovskaya A.A., Lin S.-Y., Loglio G., Miller R. .................................................. 190

Saint Petersburg, Russia XXV ESAT 2011

PI-22. Physico-chemical Properties and Phase Behaviour of Different Piperidinium-based Ionic Liquids Paduszyński K., Królikowska M., Domańska-Żelazna U.M. ..................................... 192

PI-23. The Hildebrand’s Solubility Parameters of Ionic Liquids Marciniak A., Domańska-Żelazna U.M., Paduszyński K. ......................................... 193

PI-24. Drugs solubility prediction using group contribution method Pelczarska A., Domańska-Żelazna U.M., Ramjugernath D., Pobudkowska A......... 194

PI-25. Solubility and Thermodynamic Properties of the Binary Systems Pharmaceutical + Water, or + Ethanol, or + 1-Octanol Domańska-Żelazna U.M., Pobudkowska A., Pelczarska A. ..................................... 195

PI-26. Physicochemical Properties and Activity Coefficients at Infinite Dilution for Organic Solutes and Water in the Tetracyanoborate-based Ionic Liquid Domańska-Żelazna U.M., Marciniak A., Królikowska M........................................... 197

PI-27. Thermodynamic studies on Ammonium and Phosphonium Ionic Liquids for the Separation of Aliphatic/Alcohol Mixtures Reddy P., Kaleng C., Tadie M., Deenadayalu N., Ramjugernath D. ........................ 198

PI-28. Topological analysis of phase diagrams of reactive systems: evaporation and membrane processes in comparison Toikka A., Pulyalina A., Polotskaya G. ..................................................................... 200

PI-29. Thermodynamic modeling of evaporation through membrane on the base of nonequilibrium thermodynamics approach Toikka A., Penkova A., Markelov D. ......................................................................... 202

PI-30. Thermophysical Properties of 1-butyl-1-methylimidazolium tris(perfluoroalkyl)trifluorophosphate [C4mim][FAP] Ribeiro A.P.C., Langa E., Vieira S.I.C., Goodrich P., Hardacre C., Lourenço M.J.V., Nieto De Castro C.A................................................................................................. 203

PI-31. Molecular dynamics investigation of solvent diffusion outside and inside carbon nanotube Shapovalova A.A., Burov S.V., Sizov V.V. ............................................................... 205

PI-32. Adsorption of CH4/CO2 mixtures in wet microporous carbons Shapovalova A.A., Sizov V.V., Brodskaya E.N. ....................................................... 207

PI-33. Solubility of monosaccharides in ionic liquids - measuring and correlation Carneiro A.P., Rodríguez O., Macedo E.A. .............................................................. 209

PI-34. Prediction of Gibbs Energy of Solvation and Corresponding Partition Coefficients from Molecular Simulation Garrido N.M., Jorge M., Queimada A.J., Macedo E.A., Economou I.G.................... 211

PI-35. Laccase partition in ATPS: finding some molecular descriptors Silvério S.C., Rodríguez O., Teixeira J.A., Macedo E.A........................................... 213

PI-36. Study of the influence of anion on thermal analysis of imidazolium-based ionic liquids Calvar N., Gómez E., Domínguez A., Macedo E.A. ................................................. 215

Saint Petersburg, Russia XXVI ESAT 2011

PI-37. Measurement and modeling of vapor pressures and osmotic coefficients of binary mixtures 1-propanol + CnMimNTf2 (n=2,3,4,6) at T = 323.15 K Gómez E., Calvar N., González E.J., Domínguez A., Macedo E.A.......................... 217

PI-38. Measurements and Modelling of the Phase Equilibria of Ionic Liquids and Supercritical Carbon Dioxide Manic M.S., Queimada A.J., Macedo E.A., Ponte M.N., Najdanovic-Visak V. ......... 219

PI-39. Surface tensions of esters and biodiesels from a combination of the gradient theory with the CPA EoS Oliveira M.B., Coutinho J.A.P., Queimada A.J. ........................................................ 221

PI-40. Modeling phase equilibria relevant to biodiesel production: A comparison of gE models, cubic EoS, EoS – gE and association EoS Oliveira M.B., Ribeiro V., Queimada A.J., Coutinho J.A.P. ...................................... 223

PI-41. Experimental Measurements and Modelling of CO2 Solubility in Castor, Sunflower and Rapeseed Oils Regueira T., Carvalho P.J., Oliveira M.B., Lugo L., Coutinho J.A.P., Fernández J.. 225

PI-42. Viscosity behavior of 1-ethyl-3-methylimidazolium ethylsulfate and 1-(2-methoxyethyl)-1-methyl-pyrrolidinium bis(trifloromethylsulfonyl)imide at high pressures Gaciño F.M., Paredes X., Comuñas M.J.P., Fernández J........................................ 227

PI-43. Thermal stability and thermodynamic properties of layered oxides NaNdTiO4 и Na2Nd2Ti3O10 Sankovich A.M., Zvereva I.A., Blokhin A.V., Kohut S.V. .......................................... 229

PI-44. Thermogravimetry study of ion exchange and hydratation processes in complex layered titanates and tantalates Chislov M.V., Silyukov O.I., Zvereva I.A................................................................... 231

PI-45. Thermodynamic properties and low-temperature phase transition of the Aurivillius phase Bi2NdNbTiO9 Missyul A.B., Zvereva I.A., Blokhin A.V., Kohut S.V................................................. 233

PI-46. Carbon dioxide capture using chemical absorbents: a thermodynamic approach Simond M., Ballerat-Busserolles K., Coulier Y., Rodier L., Coxam J.-Y................... 234

PI-47. Phase and chemical equilibrium in reacting system acetic acid – ethanol – ethyl acetate – water Toikka M.A., Trofimova M.A., Tsvetov N.S. ............................................................. 235

PI-48. Thermodynamics and ion flotation of lanthanoides Lobacheva O.L., Dzhevaga N.A., Litvinova T.E., Chirkst D.E., Toikka M.A. ............ 237

PI-49. Phase behavior of Methane - Toluene - Asphaltene mixture Varet G., Daridon J.L., Montel F............................................................................... 238

PI-50. Gas solubility in extra heavy oils by impedance analysis of quartz crystal resonators Daridon J.L., Cassiède M., Pauly J., Paillol H. ......................................................... 239

Saint Petersburg, Russia XXVII ESAT 2011

PI-51. Liquid-Solid Phase Transition Determination and Characterisation of the Solid Deposit in Condensate Under High Pressure Conditions Pauly J., Daridon J.L., Valbuena V........................................................................... 240

PI-52. Quartz crystal resonators for the detection of asphaltene flocculation Daridon J.L., Cassiède M., Carrier H., Pauly J., Paillol J.H...................................... 241

PI-53. Dispersions of carbon nanotubes in a mixed polar solvent Venediktova A.V., Obraztsova E.D., Vlasov A.Yu. ................................................... 242

PI-54. Sorption and anomalous diffusion of pentane in polystyrene Smolná K., Hájová H., Nistor A., Chmelař J., Gregor T., Kosek J............................ 243

PI-55. Modelling of high-impact polystyrene evolution using the Cahn-Hilliard approach Vonka M., Šeda L., Kosek J. .................................................................................... 245

PI-56. Influence of polyolefin particles morphology on their transport properties Zubov A., Šeda L., Bobák M., Kosek J..................................................................... 247

PI-57. Combination of COSMO-RS and MD for Prediction of Phase Equilibria in Systems Containing Large Molecules Sponsel E., Mokrushina L., Arlt W............................................................................ 248

PI-58. Phase Equilibria and Interfacial Properties of the System Carbon dioxide + Water Niño-Amézquita G., Enders S. ................................................................................. 250

PI-59. Aggregation Behavior of Pluronic Surfactants Dorn U., Enders S. ................................................................................................... 252

PI-60. Dependence of the micelle DEL on the ion kind and salt addition. Computer simulations with explicit solvent Brodskaya E.N., Semashko O.V. ............................................................................. 254

PI-61. Molecular dynamic simulation of AOT aggregation in nonpolar solvent Mudzhikova G.V., Brodskaya E.N. ........................................................................... 256

PI-62. Speciation and thermodynamics in solutions of multiply associating ions described using the Binding Mean Spherical Approximation (BiMSA) Simonin J.P., Bernard O., Torres-Arenas J. ............................................................. 257

PI-63. Hydrogels from a Polymer Containing Pendant Fragments of Amino Acid Crosslinked by End-Functionalized PEG and Molecular Thermodynamic Modeling of Clustering in Solution of Associating Chains Tsyrulnikov S.A., Girbasova N.V., Victorov A.I......................................................... 258

PI-64. Prediction of mixed gas solubility and solubility-selectivity in glassy polymers Minelli M., Campagnoli S., De Angelis M.G., Doghieri F., Sarti G.C. ....................... 260

PI-65. Calculation of the solubility of liquid solutes in glassy polymers Sarti G.C., De Angelis M.G. ..................................................................................... 262

Saint Petersburg, Russia XXVIII ESAT 2011

PI-66. EoS Modeling of the Phase Behavior of the Ternary System Polylactic Acid (PLA) - Water - 1,4-Dioxane for the Production of Biodegradable Scaffolds via Thermally Induced Phase Separation (TIPS) Cocchi G., Doghieri F., De Angelis M.G. .................................................................. 264

PI-67. Sorption and transport of hydrocarbons and alcohols in addition-type poly(trimethyl silyl norbornene): experimental data and comparison with NELF model predictions Galizia M., De Angelis M.G., Sarti G.C., Finkelshtein E., Yampolskii Y.P................ 266

PI-68. Molecular dynamics study of solubilization in ionic micelles Drach M., Narkiewicz-Michałek J., Niedziółka K., Sienkiewicz A., Szymula M. ....... 269

PI-69. Antioxidants Activity in Emulsions Stabilized by Ionic Surfactants Szymula M., Sienkewicz A., Narkiewicz-Michałek J., Niedziółka K., Drach M. ........ 271

PI-70. Vitamin C Antioxidative Activity in Microemulsions Narkiewicz-Michałek J., Szymula M., Sienkiewicz A., Drach M., Niedziółka K. ....... 272

PI-71. Thermodynamic properties for the heterogeneously catalyzed selective oxidation of cyclohexane in carbon dioxide expanded media by experiment and molecular simulation Merker T., Vrabec J., Hasse H. ................................................................................ 273

PI-72. Adsorption-Induced Deformation of Mesoporous Solids Gor G.Yu. ................................................................................................................. 274

PI-73. Phase behavior of systems containing biofuel components and 1,3-dioxolane derivatives as additives: experimental study and modeling Yakovleva M.A., Vorobyov E.N., Prikhodko I.V., Pukinsky I.B., Smirnova N.A., Bölts R., Constantinescu D.G., Gmehling J. ..................................................................... 276

PI-74. Line Tension of Crystal with Dispersion Forces Rusanov A.I. ............................................................................................................. 278

PI-75. Thermodynamic modeling of alternative refrigerants Vilaseca O., Llovell F., Marcos R.M., Vega L.F........................................................ 279

PI-76. Self-assembly of Small Organic Molecules in Aqueous Solutions Subramanian D., Anisimov M.A. .............................................................................. 281

PI-77. Surface Tension: a new equation based on the corresponding state principle Di Nicola G., Moglie M.............................................................................................. 282

PI-78. Thermodynamical Basis of Electromagnetic Field Impact on Multicomponent Petroleum Fluids Kovaleva L., Kamaltdinov I., Idrisova S. ................................................................... 283

PI-79. Solidification of a Binary Mixture: Application to Desalination Jaouahdou A., Safi M.J., Muhr H. ............................................................................ 284

PI-80. CO2 capture and storage: the recent developments Pires J.C.M., Alvim-Ferraz M.C.M., Martins F.G., Simões M. .................................. 285

PI-81. CO2 capture by microalgae: environment, energy and resources Pires J.C.M., Alvim-Ferraz M.C.M., Martins F.G., Simões M. .................................. 286

Saint Petersburg, Russia XXIX ESAT 2011

PI-82. Genetic programming based method to estimate binary gas diffusivity Pires J.C.M., Martins F.G. ........................................................................................ 288

PI-83. Thermodynamic properties of aqueous-alcohol solutions of sodium chloride Konstantinova N.M., Mamontov M.N., Uspenskaya I.A............................................ 289

PI-84. Thermodynamics Modeling of Dissociation Conditions of Clathrate Hydrate Refrigerants R-134a, R-141b and R-152a using the CPA equation of state Nikbakht F., Izadpanah A.A., Varaminian F. ............................................................ 291

POSTER SESSION 2 SUNDAY, 26.06.2011

PII-1. Thermodynamic properties, vaporization processes and modeling of ternary borosilicate melts Stolyarova V.L. ......................................................................................................... 295

PII-2. Thermodynamic properties of melts in the PbO-B2O3-SiO2 and ZnO-B2O3-SiO2 systems: experimental study and modeling Stolyarova V.L., Lopatin S.I., Shilov A.L., Shugurov S.M. ........................................ 296

PII-3. A Density Functional Approach to Adsorption of Oligomers on Chemically Bonded Phases Borówko M., Staszewski T., Sokołowski S............................................................... 297

PII-4. Adsorption from Binary Solutions on Chemically Bonded Phases - A Density Functional Study Staszewski T., Borówko M., Sokołowski S. .............................................................. 298

PII-5. Nematic and Demixing Behaviour in Ternary Athermal Mixtures Formed by Uniaxial and Biaxial Hard Particles Sokolova E.P., Marinichev A.N. ............................................................................... 299

PII-6. Vapor–Liquid Equilibrium in Diluted Polymer + Solvent Systems Bogdanić G., Wichterle I........................................................................................... 301

PII-7. Vapour–Liquid Equilibria in Alcohol + Hydrocarbon + Ketone Systems Bernatová S., Pavlíček J., Wichterle I. ..................................................................... 303

PII-8. Estimation of the porous structure parameters of the crosslinked macroporous poly(GMA-co-EGDMA). 1. Estimation of the specific pore volume Bogdanić G., Jovanović S.M. ................................................................................... 304

PII-9. Phase equilibria in binary mixtures of propane and phenanthrene: experimental data and modeling with the GC-EoS Breure B., Economou I.G., Vargas F.M., Peters C.J. ............................................... 306

PII-10. Experimental determination of diethyl methylphosphonate + CO2 and diethyl methylphosphonate + CH4 phase equilibrium data Mattea F., Peters C.J., Kroon M.C. .......................................................................... 308

PII-11. Prediction of Alcohol + Hydrocarbons Phase Equilibria by Monte Carlo Simulation. Application to an Ethanoled Gasoline Ferrando M., Lachet V., Boutin A. ............................................................................ 310

Saint Petersburg, Russia XXX ESAT 2011

PII-12. Experimental and modeling investigations of some thermophysical properties of CO2 rich mixtures Lachet V., Creton B., Le Roux D., Mougin P., Hy-Billiot J., Duchet-Suchaux P. ...... 312

PII-13. Thermodynamic Parameters for the MIDA Interaction with Tungsten (VI) at Different Ionic Strengths Majlesi K., Hajali N. .................................................................................................. 314

PII-14. Analogous Thermodynamic Prediction of Adsorption Excesses and Surface Tensions by Excess Quantities Kalies G., Reichenbach C., Braeuer P., Enke D. ..................................................... 316

PII-15. Analytical Integration of the Gibbs Free Wetting Enthalpy for the Adsorption of Binary Liquid Mixtures on Solids Braeuer P., Kalies G................................................................................................. 317

PII-16. Present Status of the Group Contribution Methods UNIFAC and Modified UNIFAC (Dortmund). Revision and Extension Constantinescu D.G., Gmehling J. ........................................................................... 318

PII-17. Dortmund Data Bank (DDB) and the Integrated Program Package (DDBSP) Gmehling J., Rarey J................................................................................................ 319

PII-18. NIST ThermoData Engine: Expanding Implementation of the Dynamic Data Evaluation Concept to Ternary Mixtures Diky V., Chirico R.D., Muzny C.D., Kazakov A., Magee J.W., Kroenlein K., Abdulagatov I., Frenkel M. ....................................................................................... 321

PII-19. A New Viscosity Data Correlation for Hydrogen Derived from Symbolic Regression Muzny C.D., Huber M.L., Kazakov A., Frenkel M..................................................... 322

PII-20. Modeling of the sage – supercritical CO2 extraction system at different temperatures Mićić V., Macura R., Pejović B. ................................................................................ 323

PII-21. Solar cooling by absorption system: Dimensioning and numerical simulation Grosu L., Dobrovicescu A., Untea A., Rochelle P. ................................................... 325

PII-22. Density, viscosity and speed of sound of binary mixtures of 1-butyl-3-methylimidazolium hexafluorophosfate + methanol at different temperatures and atmospheric pressure Tôrres R.B., Hoga H.E., Volpe P.L.O. ...................................................................... 327

PII-23. Excess molar volume of acetonitrile + amine mixtures at several temperatures Bittencourt S.S., Tôrres R.B. .................................................................................... 328

PII-24. High-pressure density of binary mixtures of methyl tert-butyl ether + alcohols Hauk D.B., Tôrres R.B.............................................................................................. 329

PII-25. Viscosity and Transport Properties of Ionic Liquids Ignatiev N.V., Willner H., Bernhardt E., Barthen P. .................................................. 330

PII-26. Phase behavior of 1-alkyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide and carbon dioxide Park Y.K., Hwang S.Y., Park K. ............................................................................... 332

Saint Petersburg, Russia XXXI ESAT 2011

PII-27. Hybridizing SAFT and cubic EOS: what can be achieved? Polishuk I.................................................................................................................. 333

PII-28. Global Gibbs free energy minimization and phase stability analysis in multicomponent systems using harmony search Bonilla-Petriciolet A., Soto-Bernal J.J., Rosales-Candelas I. ................................... 335

PII-29. Phase equilibria modeling of aromatic hydrocarbon and phenol mixtures with water and alcohols using the GCA-EoS Sánchez F.A., Pereda S., Brignole E.A. ................................................................... 337

PII-30. The Critical Properties of Substances Estimated by The Artificial Neural Network Method Bogatishcheva N.S., Nikitin E.D. .............................................................................. 339

PII-31. Influence of Hydrophobic Tail Structure on Biological Activity of Soft Gemini Cationic Surfactants Łuczyński J., Poźniak R., Bonarska-Kujawa D., Kleszczyńska H., Wilk K., Witek S.341

PII-32. New Ionic Liquids Containing 3-Alkoxy-2-hydroxypropyl- Moiety Poźniak R., Sokolowski A., Łuczyński J. .................................................................. 343

PII-33. Polyassociative model of solution & its application to p-T-x equilibria analysis in multicomponent semiconductor systems Moskvin P.P., Olchowik J.M., Olchowik G................................................................ 345

PII-34. Simulis® Thermodynamics: a complete thermodynamic calculation server Baudouin O., Déchelotte S., Vacher A. .................................................................... 347

PII-35. Solubility of nonsteroidal anti-inflammatory drugs in supercritical carbon dioxide Montes A., Gordillo D., Pereyra C. ........................................................................... 349

PII-36. Research Progresses of Ionic Liquids as Absorption Cycle Working Fluids Zheng D., Dong L., Wu X., Li J., Sun G.................................................................... 351

PII-37. Technical Salts as Phase Change Materials Efimova A., Ruck M., Schmidt P. ............................................................................. 353

PII-38. Experimental measurements and modelling of high pressure phase equilibria of CO2+NO2 mixture Carny S., Letourneau J.-J., Condoret J.-S. .............................................................. 355

PII-39. Vapour-Liquid Equilibria for Water + Ethanol and Water + Ethanol + NaCl. Experimental Measurements and Correlations Moreira C.M., Soares R.B., De Souza W.L.R., Mendes M.F.................................... 356

PII-40. Thermodynamic modeling of cold properties in light crude oils Coto B., Martos C., Espada J.J., Robustillo M.D., Peña J.L..................................... 359

PII-41. Excess enthalpies of bio-fuel additives: binary mixtures containing dibutyl ether (DBE) or 1-butanol and 1-hexene Montero E.A., Aguilar F., Alaoui F., Segovia J.J., Villamañán M.A. ......................... 361

Saint Petersburg, Russia XXXII ESAT 2011

PII-42. Heat capacities and densities of the binary mixture 1-butanol + cyclohexane up to 50 MPa Torine G.A., Martín M.C., Villamañán R.M., Chamorro C.R., Villamañán M.A., Segovia J.J............................................................................................................... 363

PII-43. Experimental (p, ρ, T) properties of binary mixtures of carbon dioxide with nitrogen Mondéjar M.E., Chamorro C.R., Segovia J.J., Villamañán M.A., Martín M.C., Villamañán R.M. ....................................................................................................... 364

PII-44. Predictive Correlation of Phase Equilibria for CO2 + n-Alkane Binary Systems Based on Cubic Mixing Rules Cismondi Duarte M., Rodríguez Reartes S.B., Milanesio J.M., Zabaloy M.S........... 365

PII-45. Calculation Of Critical Lines Of Ternary Systems Pisoni G.O., Rodríguez Reartes S.B., Cismondi Duarte M., Zabaloy M.S. .............. 366

PII-46. Solubility prediction of 1,8-cineole in a solvent mixture at high pressure Zacur Martínez J.L. .................................................................................................. 367

PII-47. Influence of the size ratio on the volumetric properties of binary mixtures Balankina E.S........................................................................................................... 369

PII-48. Effect of gravitational force on two-phase flow regimes during condensation inside a microfin tube Akhavan-Behabadi M.A., Mohseni S.G.................................................................... 371

PII-49. Determination of the operating parameters of an evaporator crystallizer. Liquid/solid equilibria in the NaCl-NaOH-H2O ternary system Dhenain A., Bougrine A.J., Frangieh M.R., Delalu H. .............................................. 373

PII-50. LLE in the Pyrrolidine/Water/NaOH Ternary System - Experimental Study and Critical Point Determination Frangieh M.R., Bougrine A.J., Tenu R., Dhenain A., Counioux J.J., Goutaudier C. 375

PII-51. Distillation Path in the Liquid-Vapor Equilibria Pyrrolidine/Water/N-Aminopyrrolidine Ternary System Goutaudier C., Frangieh M.R., Tenu R., Bougrine A.J., Dhenain A. ........................ 376

PII-52. The Influence of the Seed Preparation on Granulometric Characteristics and Polymorphism at Glycine Crystallization Prlić Kardum J., Hrkovac M., Duvančić M., Matijašić G. .......................................... 378

PII-53. Choline Based Ionic Liquid Properties Makowska A., Szydłowski J. .................................................................................... 380

PII-54. Isotope effects on miscibility of [C8MIM][NTf2], [C8MIM][BF4] and [C8MIM][PF6] with hexanol and heptanol Siporska A., Szydłowski J. ....................................................................................... 382

PII-55. Relationship between refractive index and density of mixtures containing imidazolium ionic liquids with water and ethanol Rilo E., Domínguez-Pérez M., Segade L., Vila J., Varela L.M., Cabeza O. ............. 384

Saint Petersburg, Russia XXXIII ESAT 2011

PII-56. Volumetric Behaviour of Binary and Ternary Liquid Systems Composed of Ethanol, Isooctane, and Toluene at Temperatures from 298.15 K to 328.15 K Linek J., Morávková L., Wagner Z., Sedláková Z..................................................... 386

PII-57. Measurement of Solid–Liquid and Liquid–Liquid Equilibria in Organic System Containing Ionic Liquid [emim][NTf2] Sedláková Z., Rotrekl J., Bendová M., Vrbka P., Aim K........................................... 387

PII-58. Comparison of Excess Volumes for Two Ternary Systems containing (Toluene + Isooctane) with Ethanol or 1-Butanol Morávková L., Wagner Z., Sedláková Z., Aim K. ..................................................... 389

PII-59. Application of Thermodynamic Consistency Lines to the VLE and LLE Data Kato S., Tachibana H. .............................................................................................. 391

PII-60. High-Pressure Phase Equilibria of CO2 + Styrene and CO2 + Vinyl acetate. Use of different experimental methods Dohrn R., Haverkampf V., Peper S. ......................................................................... 393

PII-61. Phase Equlibria of Carbon Dioxide + 1-Pentanol System at High Pressures Secuianu C., Feroiu V., Geană D............................................................................. 395

PII-62. Thermochemistry of Biofuels: Reference Materials for Combustion Calorimetry of Liquids Zaitsau Dz.H., Emel’yanenko V.N., Verevkin S.P., Pagel R., Sarge S.M., Wolf H., Morice R. .................................................................................................................. 398

PII-63. About the capability of the PPR78 model to predict excess-enthalpy and excess-heat capacity data Privat R., Qian J., Jaubert J.-N................................................................................. 399

PII-64. Phase equilibria in alkenes-containing binary systems from the Peng Robinson EoS using temperature-dependent BIPs (kij(T)) calculated through a group-contribution method Qian J., Privat R., Jaubert J.-N................................................................................. 400

PII-65. Improvement of TG Resolution by Heating Rate Conversion Simulation Method Okubo N., Rumyantsev A......................................................................................... 401

PII-66. Characterization of UV Curing Polymers by Photochemical Reaction DSC System Okubo N., Rumyantsev A......................................................................................... 402

PII-67. Effect of the alkyl chain positions on the desulfurization ability of [HMMPy][NTf2] ionic liquids Rodríguez-Cabo B., Francisco M., Soto A., Arce A.................................................. 403

PII-68. Formation and characterization of oxide nanoparticles in ionic liquids Rodríguez-Cabo B., Palmeiro I., Rodil E., Soto A., Arce A. ..................................... 404

PII-69. Citrus essential oil deterpenation by liquid-liquid extraction using 1-ethylpyridinium ethylsulfate ionic liquid as solvent Lago S., Rodríguez H., Soto A., Arce A. .................................................................. 405

Saint Petersburg, Russia XXXIV ESAT 2011

PII-70. Extraction of Sulfur or Nitrogen containing organic compounds from aliphatic hydrocarbons using ionic liquids Kędra-Królik K., Mutelet F., Jaubert J.-N.................................................................. 407

PII-71. Thermodynamic Characterization of Trigeminal Tricationic Ionic Liquids Mutelet F., Moise J.-C., Skrzypczak A., Jaubert J.-N. .............................................. 408

PII-72. Thermodynamic study of azeotropic mixtures of interest in the chemical and pharmaceutical industry Luis P., Parvez A., Van Der Bruggen B.................................................................... 409

PII-73. Electrostatic charging and charge transport by hydrated amorphous silica under high voltage electric field Volpe P.L.O., Perles C.E.......................................................................................... 410

PII-74. Interaction of excess enthalpies and phase equilibria during supercritical antisolvent (SAS) precipitation Pando C., Renuncio J.A.R., Cabañas A., Zahran F., Morère J. ............................... 411

PII-75. Ultrasonic speeds and isentropic functions of aqueous mixtures of 1-propoxypropan-2-ol from 283.15 to 303.15 K Lampreia I.M.S., Santos A.F.S., Reis J.C.R., Figueiras A.O., Moita M.L.C.J., Pinheiro L.M.V. ....................................................................................................................... 413

PII-76. Chemical activities in aqueous mixtures of 1-propoxypropan-2-ol at 283.15 K Santos A.F.S., Silva J.F.C.C., Moita M.L.C.J., Lampreia I.M.S................................ 414

PII-77. Receptor properties of nanoporous material based on oligopeptides toward vapor of organic compounds Efimova I.G., Ziganshin M.A., Gorbatchuk V.V., Ziganshina S.A., Chuklanov A.P., Bukharaev A.A. ........................................................................................................ 415

PII-78. Thermodynamic Modeling of the Phase Equilibrium of CO2 – Organic Acid Systems with the UMR-PRU Model Pappa G., Louli V., Stamataki S., Magoulas K., Voutsas E. .................................... 417

PII-79. Thermodynamic modelling of mixtures containing antioxidants, organic solvents and ionic liquids Panteli E., Voutsas E................................................................................................ 418

PII-80. Experimental studies of the folding thermodynamics of adsorbed proteins Choosri T., Wendland M........................................................................................... 419

PII-81. Phase Diagram Studies for Extraction of Alcohols from Azeotropic Mixtures Using Trifluoroethanol at Atmospheric Pressure Atik Z., Kerbou W., Kritli A. ....................................................................................... 420

PII-82. Thermodynamic properties of some α,ω-halogenoalkanes Chorążewski M., Grolier J.-P.E. ............................................................................... 421

PII-83. Corrosion of copper in 1-alkyl-3-methylimidazolium tetrafluoroborates contaminated with water and chlorides Marczewska-Boczkowska K., Kosmulski M. ............................................................ 423

Saint Petersburg, Russia 1 ESAT 2011

ABSTRACTS


Saturday, 25.06.2011

PLENARY SESSION


Industrial Requirements for Thermodynamics and Transport Properties - Before and Now

Hendriks E.1, Kontogeorgis G.M.2, Dohrn R.3, De Hemptinne J.-C.4, Economou I.5, Fele Žilnik L.6, Vesovic V.7

1 - Shell Global Solutions, Shell Technology Centre Amsterdam, Grasweg 3, 1031 HW Amsterdam, The Netherlands

2 - Center for Energy Resources Engineering (CERE), Department of Chemical and Biochemical Engineering, Technical University of Denmark, DK-2800, Lyngby, Denmark

3 - Bayer Technology Services GmbH, Process Technology, Kinetics, Properties & Modeling, Building B310, D-51368 Leverkusen, Germany

4 - IFP, 1& 4 Avenue de Bois-Préau, 92852 Rueil-Malmaison Cedex, France 5 - The Petroleum Institute, Department of Chemical Engineering, PO Box 2533, Abu Dhabi,

United Arab Emirates 6 - National Institute of Chemistry, Department of Catalysis and Reaction Engineering, PO Box

660, SI-1001 Ljubljana, Slovenia 7 - Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ,

United Kingdom

[email protected]

An investigation on industrial requirements for thermodynamic and transport properties has been recently carried out by the Working Party on Thermodynamic and Transport properties (http://www.wp-ttp.dk/) of the European Federation of Chemical Engineering, EFCE (http://www.efce.info/). This presentation will summarize the major results from this investigation and compare them to those of previous investigations/reviews from industry and academia.

The EFCE Working Party survey is based on the analysis of the results collected as answers to a questionnaire which was sent to a number of technical people in companies in the oil & gas, chemicals and pharmaceutical / biotechnology sectors. Twenty eight companies have provided answers which formed the basis for the analysis.

The presentation will include different general aspects of industrial needs in terms of systems, conditions, models and implementation as well as some more specific requirements which should be met in the future by some of the prominent models in the field e.g. SAFT.


Phase behaviour, solubility and salting out in aqueous solution: SAFT approaches and computer simulations

Galindo A.

Department of Chemical Engineering, Imperial College London, UK

[email protected]

The solubility of organic molecules in aqueous solution is of widespread interest in fundamental and applied sciences, in the design of industrial processes, and in geochemical, environmental, biological and chemical systems. The presence of ions in these systems affects their phase behaviour and is of special interest when determining the partitioning of hydrophobic molecules in aqueous phases. Adding salts to an aqueous solution of a hydrophobic molecule can result in either a decrease (salting out) or an increase (salting in) of the solubility of the hydrophobe; different salts result in different effects.

In SAFT approaches, short-range attractive sites are used to mediate the hydrogen bonds present in water. These follow the original idea proposed in the thermodynamic perturbation theory of Wertheim, and although providing a simplified view of the real system, SAFT approaches are successful in representing many of the features of complex phase behaviour of aqueous systems. I will briefly review SAFT models for water, and discuss recent theoretical developments from our group; in particular the use of group contribution models for aqueous solutions, the extended capabilities of a SAFT-Mie version based on a generalized Lennard-Jonesium potential, and the treatment of electrolytes and salting out. Finally, a computer simulation model is used to study aqueous solutions of methane and discuss solubility and salting out in more detail.

Invited Lecture


Thermodynamic Fundamentals of Solid Strength

Rusanov A.I.

St. Petersburg State University, Russia

[email protected]

Existing thermodynamic potentials are insufficient for the thermodynamic description of an arbitrarily loaded solid body. For example, Gibbs energy only works as a thermodynamic potential provided a body is subjected to uniform pressure. To embrace the general case, the generalized Gibbs energy *G is introduced as

*

( )

( )A

G F dA≡ − ⋅∫∫ P u , (1)

where F is free energy, P is an external force (stress) per unit surface as a function of location on the surface (A) of a solid, u is the displacement vector at the surface, and A is the surface area, the integration being carried out over the whole outer surface of the solid (including the crack surface for a surface crack and excluding the crack surface for a crack situated in the bulk). Classical consideration of the crack formation work (made by Griffith [1] for the 2d case and by Sack [2] for the 3d case) included thermodynamic surface tension (cleavage work) σ but disregarded line tension that can be of some significance for a nanocrack. We introduce the thermodynamic line tension κ of a crack as [3]

c1 ( )dAL ∞κ ≡ σ − σ∫ →

0

00

( , ) 2 [ ( , ) ]r

r r dr∞κ θ ≡ σ θ − σ∫ , (2)

where L is the crack front length, σ and ∞σ are local surface tension and its constant value far from the crack tip, cA is the crack surface area, and the integration is carried out over the whole crack surface. Since ,∞σ < σ Eq. (2) shows κ to be negative at least for an empty crack. The second form of Eq. (2) refers to a wedge-shaped crack with a straight front line: 2θ is a dihedral crack angle, r is the distance from the crack tip, and

0r is the coordinate of the crack lips.

The work of formation of a surface crack of depth c in an elastic solid is characterized by the equation

*d ( ) d2 cos

d dG w wLc c R c∞

∂ κ + κ + ∂κ θ = σ θ + + + ∂ ∂θ , (3)

where w is the excess elastic energy related to the crack (already estimated by Griffith [1] and Sack [2] as a function of c) and R is the local curvature radius of the crack front

Invited Lecture


line (R = c for a circular crack). Since a spontaneous process corresponds to *d /dG c < 0, the criterion of immediate brittle fracture following from Eq. (3) is

( ) d2 cos 0d

w wc R c∞

∂ κ + κ + ∂κ θσ θ + + + <∂ ∂θ

. (4)

Finding the dependence of line tension κ on c and θ implies a certain mechanism of the crack propagation. We have analyzed two mechanisms: (a) the conformal growth of a crack when the dihedral angle θ is maintained; (b) the depth mechanism with a fixed distance between the crack lips when deepening the crack is accompanied with diminishing θ. Thermodynamic estimations showed the second mechanism energetically more favorable. Detailed calculations were performed for a molecular solid with dispersion interactions. It was obtained for the dimensionless line tension /2 ∞κ ≡ κ σ δ (δ is the crystal spacing)

0

0 0

ln11 sin hh h∞

κ = κ − + θ

, 11sin sin ,

2−

∞κ = − θ − θ (5)

where ∞κ is the limiting κ -value for an infinitely deep crack (at 0 )h → ∞ and

0 0 /h h≡ δ is the dimensionless maximum width of a nanocrack. For the depth mechanism of the crack growth, the dependence of line tension on the dimensionless crack depth /c c≡ δ is

1/22 2

02 20 0 0 0

ln4 2 3 11 12

hc ch h h h

− κ = − + + − −

. (6)

A linear approximation is good for a sufficiently developed crack ( 2 20/ 3/4c h >> )

20 0, 2 , ( 1)/Kc K c K h h∞κ = − κ = − σ ≡ − . (7)

Finally, the ultimate strength tP was calculated and compared with classical results G

tP by Griffith for the 2d case [1] and StP by Sack for the 3d case [2] as

( )1/2

1/2tG 2

t 0 0

1 11 1P KP h h

= − = − +

,

1/2

tS

t 0

21PP h

= −

(8)

to show the effect of line tension to be twice as much in the 3d case as compared with the 2d case [3].

References [1] A.A. Griffith, Phil. Trans., (1921), A221, 163-198. [2] R.A. Sack, Proc. Phys. Soc., (1946), 58, 729-736. [3] A.I. Rusanov, Int. J. Fract., (2010), 161, 53-63.



SESSION 1: Process and Product Design


Thermodynamic modelling of thermal salt production process

Coussine C.1,2, Cezac P.2, Serin J.-P.2, Contamine F.2, Reneaume J.-M.2, Dubourg K.1, Cambar J.1

1 - Institut du thermalisme, Université Victor Segalen Bordeaux 2, 8 rue Sainte Ursule, 40100 Dax, France

2 - Laboratoire de Thermique, Energétique et Procédés (LaTEP), Université de Pau et des Pays de l’Adour, rue Jules Ferry, BP 7511 Pau cedex, France

[email protected]

The aim of this study is to propose a general dynamic model based on a thermodynamic approach that can accurately predict the resulting phase distribution and phase composition in salt water. The proposed model is used to simulate a production process of thermal salt (for cosmetology). Furthermore, the process is based on sustainable development principles. Indeed, the raw material is exclusively a natural resource (salt spring water) and the by-product of process can be directly used as concentrated thermal water in spas. Besides, renewable energy like solar energy can be used in this process.

The model is based on a thermodynamic description of the physical-chemical phenomena occurring in a Gas-Liquid-Solid electrolytic system. Two types of equilibriums are considered: phase equilibrium and chemical reaction equilibrium. So the equations used are: the two types of equilibrium, the partial mass balance and the electroneutrality. The non-ideality of solution is described by Pitzer’s model [1] (to calculate the activity coefficients). The non-linear differential system is solved in dynamic state by the Gear method. Precipitation of different salts is considered by the integrator as event using the thermodynamic solubility constants.

Experimental data are compared with the calculated values in order to validate the use of the model for natural waters applications. We experiment the process with thermal water of Dax like raw material. The lab-pilot is a water jacketed vessel maintained at constant temperature with a thermostated bath. The solution is stirred with a magnetic bar stirrer. The simple apparatus used is shown in figure 1.


Figure 1 : Lab-pilot The concentrations of species in the saturated solution (clear supernatant solution) are determined by using ion chromatography. References [1] K.S Pitzer, Activity coefficients in electrolyte solutions (2nd edition), CRC Press, Boca Raton (1991).


Development of Functional Textiles for Summer Wear

Sánchez-Silva L., Rodríguez J.F., Sánchez P.

Department of Chemical Engineering, University of Castilla-La Mancha, Spain

[email protected]

Introduction The emerging technologies based on microencapsulation are able to confer new properties and add value to the textiles that are not possible or cost-effective using other technologies [1-3]. Microencapsulated phase change materials (PCM) can be incorporated into textile structures to produce fabrics with thermo-regulating properties. A thermo-regulating fabric is a smart material that has the property of offering suitable response to changes in external temperature or to external and environmental stimuli.

To apply these PCM microcapsules to fabrics, their thermal activity must work in a range of skin temperature and be harmless to the skin. When the body is at its normal temperature there are certain temperature ranges common to certain parts of the body. The core of the body, or the abdominal area, and the head normally maintain an average skin temperature higher than that associated with other areas of the body. Generally, the overall average comfortable skin temperature is 33.3°C, and if this cannot be maintained, a person begins to feel uncomfortable [4].

In this study, the commercial paraffin Rubitherm® RT31 was used as PCM for developing a fabric with thermo-regulating properties. Its melting point is about 31°C, and it allows the PCM to be stabilized in a slushy state below the comfortable skin temperature.

The aim of this work was to investigate the production of textiles with thermoregulating

properties using microcapsules containing Rubitherm® RT31. Furthermore, a comparison was made of the thermal insulating effect of the textiles with thermo-regulating properties according to the used textile substrate.

Results Seven fabrics substrates for different textile applications were used. Their description and properties are shown in Table 1.


Table 1. Textile substrates characterization and their textile uses.

Sample Composition Area Weight (g m−2)

Thickness (mm)

Uses

A 82% Polyester 18% Polyurethane

296 1.50 Soft-Shell fabric with an intermediate polyurethane membrane for cold protection

B 11% Elastane 35% Polyamide 54% Polyester

270 1.34 Soft-Shell fabric with an intermediate polyurethane membrane for cold protection

C 100% Polyamide 202 0.48 Green fabric for military uses D 100% Polyester

coating with 100% PVC

121 0.27 Yellow fabric for garments of high visibility

E 40% Polyester 60% Cotton

185 0.35 Openwork fabric in blue tone for medical garments uses

F 100% Polyamide 328 0.61 Military printed fabric for military uses

G 100% Cotton 158 0.30 Fabric used for upholstery, sheets, curtains and garments

Thermal performance of different coated textiles with thermo-regulating properties with 35 wt. % of PCM microcapsules as a function of the kind of textile substrate was evaluated by DSC analyses (Figure 1). It can be seen that all treated textile substrates allow to obtain thermo-regulating properties with acceptable latent heat storage capacities. It was found that the melting transition points in the coated fabrics from A to G changed 0.72, 0.01, 0.13, 0.37, 0.13, -0.35 and 0.01 °C, respectively. This indicated that the kind of textile substrate have not significant effect on the microcapsules melting effect.

Table 2 summarizes the latent heat storage capacity, the necessary time to decrease the

temperature of coated textiles from 33 to 25 °C, the latent heat accumulated in 1 m2 of fabric substrate associated with each sample and the amount of PCM microcapsules added on each textile substrate. There are not important differences in the latent heat storage capacity and the amount of retained PCM microcapsules depending on the kind of used substrate textile. Coated textiles A and B exhibit the highest latent heat and a long thermoregulatory effect, due to the soft shell characteristics and the large thickness of these fabrics that allow to accommodate a high amount of PCM microcapsules and improve the resistance of heat transfer, respectively. Furthermore, the lowest latent heat storage capacity for samples having polyamide as textile substrate (samples F and C) suggests that this composition does not allow the incorporation of a large amount of PCM microcapsules into the fabric. Nevertheless, small differences of latent heat storage capacity were obtained. According to these results, the heat transfer through


fabric depends on the quantity of PCM microcapsules added on the coating binder but also the textile composition and structure.

Figure 1. DSC thermograms of the different coated textiles with 35 wt.% of microcapsules containing Rubitherm® RT31. Table 2. Thermal properties of the thermo-regulating textiles.

Sample LH (J g-1) Duration of the heat release from 33 to 25°C (s)

Latent heat accumulated in 1 m2 of fabric substrate (kJ m-2)

PCM microcapsules added on the textile (wt. %)

A 19.4 79 5.7 25.6 B 18.1 62 4.9 23.9 C 13.5 65 2.7 17.8 D 16.3 28 4.4 21.5 E 14.3 42 2.6 18.9 F 11.1 67 3.6 14.7 G 14.4 48 2.3 19.0

References [1] G. Nelson, Int. J. Pharm., (2002), 242, 55–62. [2] W. Baumann, K. Laccase, In Textile Chemicals: Environmental Data and Facts, Springer, Berlin, 2004, pp. 468–482. [3] P. Monllor, L. Sanchez, F. Cases, M.A. Bonet, Text. Res. J., (2009), 79, 365–380. [4] R.M. Laing, P.E. Ingham, Cloth. Textile Res. J., (1984-1985), 3, 25-33.

A

B

C

D

E

F

G

-0.92

0.22

Hea

t Flo

w (W

/g)

-20 0 20 40 60 80

Temperature (°C)Exo U p Univ ersal V 4. 2E TA I ns trum ents


Paints with IoNanofluids as pigments for improvement of heat transfer on architectural and heat exchangers surfaces

Vieira S.I.C., Ribeiro A.P.C., Lourenço M.J.V., Nieto De Castro C.A.

Departamento de Química e Bioquímica and Centro de Ciências Moleculares e Materiais Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal

[email protected]

Introduction

Paint coatings are an efficient, very affordable and available method of controlling the flow of energy inside a building [1-3]. By covering walls in hospitals, spas, domestic residences, but also over solar collectors, steam engines, heat pipes and refrigerators, we can have a better reign over our settings, reducing the amount of electricity spent with air conditioners, since these coatings can retain the heat when it is too warm, and dissipate it when it is uncomfortably cold. The paints are used as coatings, whose application has the objective to decorate and/or to protect the substrate and to optimize its function [4]. One of the most influential components in paints properties is the pigment.

In the present paper we report the development of new pigments based on ionic liquids (IL), crystal violet and its functionalization with carbon nanotubes (CNT’s) – IoNanofluids – to produce paint coatings to improve the heat transfer characteristics of these surfaces.

IL and nanomaterials are by far two of the most important developing areas of chemistry, especially in novel applications in chemical processing and new materials. The joint use of these areas in creating functionalized nanomaterials generates an excellent expectation in the new trends of technological chemistry.

IL have excited interest due to their stability and thermal conductivity, low flammability [5] and ability to function as paint additive [6] without increasing the volatile organic compounds (VOC) percentage, making them adequate materials for applications in paint coatings.

In addition, it has been discovered that CNT’s and room-temperature ionic liquids can be blended to form gels that may be used to make novel electronic devices, coating materials, and antistatic materials, namely dye-sensitized solar cells [7]. Aida and co-workers [8,9], prepared "bucky gel" stable materials by grinding suspensions of high-purity CNT’s in imidazolinium cation-based IL and enhanced recently the possibilities of IL for design of soft materials based on CNT’s. These authors showed that a covalent functionalization of dispersed CNTs in bucky gels with aryldiazonium salts originated the arylation of the sidewall of CNT’s, in a smooth and homogeneous fashion.

The spectral selectivity of the coatings was evaluated by the determination of the solar absorbance on the UV/Vis/NIR region and the thermal emmitance in the thermal


infrared. It was verified that the addition of IoNanofluids (bucky gels) increases the spectral selectivity of the paint base, improving the coating efficiencies. These studies show that these materials are promising for their application in low VOC coatings for heat transfer [10]. Application to the conversion of solar energy in thermal energy is under way.

After the accomplishment of the necessary tests, we foresee the existence of a new product with a high energy performance, the substitution of some currently dangerous products for the other more innocuous, and simultaneously the possibility of application of the new paint in the camouflage/improvement of the landscape, superior to the existing paints in the market.

References

[1] Z. C. Orel, Solar Energy Materials & Solar Cells (1999), 57, 291-301. [2] Z. C. Orel, M. K. Gunde, Solar Energy Materials & Solar Cells (2001), 68, 337-357. [3] Z. C. Orel, M. K. Gunde, M.G. Hutchins, Solar Energy Materials & Solar Cells (2005), 85, 41-50. [4] M. E. M. Almeida, “Guia sobre a protecção anticorrosiva na indústria automóvel”, Ed. INETI, Lisboa, Portugal, (2000). [5] M. Gorlov, L. Kloo, Dalton Trans., (2008), 2655-2666. [6] B. Weyershausen, K. Lehmann, Green Chem. (2005), 7, 15-19. [7] H. Usui, H. Matsui, N. Tanabe, S. Yanagida, J. Photochem. Photobiol. A Chem. (2004), 164, 97-101. [8] T. Fukushima, A. Kosaka, Y. Ishimura, T. Yamamoto, T. Takigawa, N. Ishii, T. Aida, Science, (2003) 300, (5628), 2072-2074. [9] T. Fukushima, T. Aida, Chem. Eur. J., (2007), 13, 5048-5058. [10] S. I. C. Vieira, “Funcionalização de nanomateriais para aplicações em conversão térmica de energia solar”, MSc Thesis, Faculdade de Ciências da Universidade de Lisboa, (2008).


Thermodynamic study of systems CO2-AMINE-WATER for CO2 capture processes

Ballerat-Busserolles K., Simond M., Coulier Y., Rodier L., Coxam J.-Y.

Thermodynamique et Interactions Moleculaires, CNRS, UMR 6272, Univ. Blaise Pascal, BP 10448, F-63000 CLERMONT-FERRAND, FRANCE

[email protected]

The carbon dioxide released in the atmosphere is the principal cause of the so-called greenhouse effect, leading to global warming. According to the Kyoto protocol the emission of greenhouse and acid gases, resulting from the combustion of fossil fuels, or present as constituents of natural gas, must be reduced. Different national and international research projects have emerged and the present work is a thermodynamic study carried out in the frame work of the ANR CapCO2 (French National Research Agency) on the capture of CO2 in post-combustion processes.

Our objective is to obtain reliable thermodynamic data for different amines in order to correlate the amine structure and the absorption properties. More specifically the enthalpies of solution and the solubilities of acid gases in aqueous solutions of selected amines are determined simultaneously to the solution density and the amine dissociation constants.

The enthalpies of solution are directly measured by a calorimetric method at temperatures 323 K and 373 K and pressures up to 2 MPa. The solubilities are deduced from the analysis of the enthalpic data. A customized flow mixing unit adapted to the SETARAM C-80 calorimeter [1] was used to measure the enthalpy of solution of CO2 with aqueous solutions of amine. The experiments are carried out at constant temperature and pressure for different gas loadings up to the saturation of the solvent.

The densities of the solutions are determined at 303.15 K and different pressures using a vibrating tube densimeter DMA 620 from Anton Paar. The dissociation constants are determined at atmospheric pressure and temperatures between 298 K and 333 K using an automatic titrator from Mettler-Toledo equipped with a glass electrode.

The influence of the structure of the amine on the thermodynamic properties will be discussed simultaneously to the intensive parameters. The compilation of all the data will be used to develop and optimize rigorous thermodynamic models.

References [1] H. Arcis, L. Rodier, J.-Y. Coxam, J. Chem. Thermodyn. 39 (2007), 878-887.


Thermodynamic modeling of sour gas cleaning process with alkanolamine

Sadegh N.1, Kontogeorgis G.M.1, Stenby E.H.2, Thomsen K.1

1 - Center for Energy Resources Engineering (CERE), Department of Chemical and Biochemical Engineering, Technical University of Denmark

2 - Center for Energy Resources Engineering (CERE), Department of Chemistry, Technical University of Denmark

[email protected]

Some 40% of the world’s remaining gas reserves are sour or acid, containing large quantities of CO2 and H2S and other sulfur compounds. Many large oil and gas fields have more than 50% CO2 and H2S content. In the gas processing industry absorption with chemical solvents has been used commercially for the removal of acid gas impurities from natural gas. Alkanolamines, simple combinations of alcohols and ammonia, are the most commonly used category of chemical solvents for acid gas capture.

Accurate estimation of both gas solubility and thermal properties is crucial for a better design of amine based acid gas removal processes. Since the steam cost is over half of the total plant costs, prediction of heat of absorption is of great importance to increase cost efficiency. Most of the used thermodynamic models do not provide acceptable prediction on acid gas solubility and heat of absorption with a unique set of parameters. Even for the simulation of acid gas solubility in alkanolamines the existing models may have large errors when extrapolated to high pressures, high wt% of amine, mixed CO2 and H2S gasses.

In this work the Extended UNIQUAC model [K. Thomsen, P. Rasmussen, Chem. Eng. Sci. 54 (1999) 1787–1802] is used toestimate various thermodynamic properties of the water/ acid gas (CO2, H2S and both) / alkanolamine (MEA, MDEA and blend) systems required for designing natural gas treating units.Parameters are optimized from the available experimental solubility and thermal data, covering high pressure, high temperature and high amine content. The obtained results revealed that the Extended UNIQUAC model can effectively predict both the gas solubility and heat of absorption over an extensive range of conditions with only a unique set of parameters.


Study of Fruit Waste Reuse as New Thermal Absorbing Materials

Queirós C.S.G.P., Vieira S.I.C., Lourenço M.J.V.

Departamento de Química e Bioquímica e Centro de Ciências Moleculares e Materiais Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal

[email protected]

Food and agroindustrial waste can be an advantageous resource for energetic utilization in thermal energy processes [1]. Every year, over 220 million tones of food waste is produced in Europe [2], making the implementation of methods for its reuse an environmentally friendly and economically viable solution. Materials that have the ability to concentrate heat in their system, releasing it afterwards to the environment or absorbing heat from its surroundings can be used in several heat transfer applications, contributing to reduce the energy consumption in home heating systems, air conditioning and industrial processes. Among the food and agroindustrial waste produced, cereals and fruits generate high amounts of waste materials such as peels, hard shells, seeds and stones. Although most of the recent literature focuses on the use of these natural materials as adsorbents (activated or carbonized forms) [3-5] or as a resource for biofuels [6], it is known the use of fruit seeds and cereals as heat transfer fillers in pads for pain relief [7], presenting high heat storage. The solids are already successfully used as biomass fuels, and can replace glass or other zeolite materials used in boiling/condensation industrial/pilot plants. The liquid/emulsions that have a high heat capacity and thermal conductivity can be applied as biodegradable heat transfer fluids, replacing the actual petroleum derived oils used in industry and domestic heating. For such applications it is crucial to know with accuracy the thermophysical properties since monitoring is fundamental [8]. The accurate knowledge of the heat capacity of such systems becomes then a valuable tool. The interest and usefulness of the exploratory work has risen from the lack of knowledge about the thermal properties of powdered samples of these materials. Therefore the paper presents heat capacity, thermal diffusivity and thermal conductivity of several of these materials, as well of the thermal conductivity of their suspensions in an ionic liquid, [C4mim][Tf2N], here designated for the first time as IoBiofluids, and in water with a surfactant. Experimental measurements of thermal diffusivity and heat capacity show that thermal conductivity of walnut shell powder is greater than thermal conductivity of the cherry stone powder, which in turn is higher than that of the hazelnut shell powder. In this experimental study it was possible to ascertain a bigger similarity between the nut shell and the cherry stone, pertaining to both their structures and their thermal properties (thermal conductivity and heat capacity). The thermal conductivity and the heat capacity of the nut shell have higher values when compared to the other samples analyzed.


The thermal conductivity versus temperature study of suspensions containing 2% (w/w) of powdered samples in water and surfactant has shown that the addition of several powders to this medium can heighten this property, making the application of fruit residues to heat transfer fluids a viable option [9]. This work focuses exclusively on the non edible portions of the fruit to avoid the "food/fuel dilemma" [10].

Figure 1. Thermal conductivity variation with temperature for the samples C2F (cherry stones), NSL (walnut shells) and AVE (hazelnut shells).

References

[1] B. Digman, D.-S. Kim, Environmental Progress, (2008), 27, No.4, 524-537. [2] K. Waldron, C. Faulds, A. Smith (Editors), “Total Food: Exploiting co-products – minimizing waste”, Total Food Proceedings – Institute of Food Research, Norwich, UK (2004). [3] C. J. Durán-Valle, M. Gómez-Corzo, J. Pastor-Villegas, V. Gómez-Serrano, Journal of Analytical and Applied Pyrolysis, (2005), 73 (1), 59-67. [4] M. Olivares-Marín, C. Fernández-González, A. Macías-García, V. Gómez-Serrano, Adsorption, (2008), 14 (4-5), 601-610. [5] V. Hernández-Montoya, M. A. Montes-Morán, M. P. Elizalde-González, Biomass and Bioenergy, (2009), 33, 1295–1299. [6] P. Mondal, M. Basu, N. Balasubramanian, Biofuels, Bioprod. Bioref., (2008), 2, 155–174. [7] Y. Gaudreault, M. Lebeau, R. Robitaille, “Thermotherapeutic Pad” US Patent 5300104. Apr. 5, (1994) [8] J. M. P. França, C. A. Nieto de Castro, M. Matos Lopes, V. M. B. Nunes, J. Chem. Eng. Data, (2009), 54 (9) 2569–2575. [9] C. S. G. P. Queirós, MScThesis “Estudo do aproveitamento de resíduos de frutos como novos materiais absorvedores térmicos”, Faculdade de Ciências da Universidade de Lisboa, Portugal (2010) [10] L. D. Gomez, C. G. Steele-King, S. J. McQueen-Mason, New Phytologist, (2008), 178, 473–485.


Modeling of the production of hydrogen from saccharides as main ingredients of biomass

Müller K., Lobanova O., Mokrushina L., Arlt W.

Friedrich-Alexander-University Erlangen-Nuremberg, Chair of separation science and technology, Germany

[email protected]

Biomass as a new source of energy to replace fossil fuels has raised much attention in recent years. Many of the biomass utilization processes developed in the past, turned out to be highly ineffective in terms of energy balance. Some publications show that the amount of energy needed for the production of biodiesel and bioethanol, for example, could exceed the energy derived from the product.

The key aim of this research project is to investigate the reaction thermodynamics of different biomasses systematically. Based on these data, the selection of bioresources and processes can be supported to develop energy effective methods for gaining energy from biomass.

As a model reaction, the conversion of saccharides to hydrogen and carbon dioxide has been selected. This reaction has already been implemented as a high temperature process. Since in terms of energy, it is desirable to carry out reactions at mild conditions, the potential of realizing it at low temperatures was researched from the thermodynamic viewpoint.

By balancing enthalpy and Gibbs’ energy of the respective model-reactions, the equilibrium yields and conversions have been explored. The deviations from the ideality have been taken into account by activity and fugacity coefficients. Since the availability of data for long chain saccharides is limited, models have been developed and validated to predict these values.

It has been shown that the production of hydrogen from saccharides at low temperatures is thermodynamically possible. With the increasing chain length of a saccharide, the equilibrium is further shifted toward the products. By adding an inert gas, the gaseous products are diluted and the equilibrium conversion can be increased.

This project has been supported by the Deutsche Forschungsgemeinschaft (Projektnummer: AR 236/34-1).


Thermodynamic modeling of ethanol/gasoline blends

Soria T.M., Gonzalez Prieto M., Pereda S., Bottini S.B.

PLAPIQUI, Universidad Nacional del Sur – CONICET, Argentina

[email protected]

Bioethanol fuel blends play nowadays an important role in countries like Brazil and USA. Moreover, policies worldwide promote blending of fossil- and bio-fuels to meet sustainable targets. Ethanol has a high impact in the final fuel properties. The high non-ideality of mixtures containing ethanol and hydrocarbons strongly affects the phase behavior of the blend and consequently has an impact on its storage, transportation and use in engines. French and Malone[1] discussed the effect of adding ethanol to gasoline, in several properties: i) volatility (i.e. Reid vapor pressure, ASTM D-86 Distillation, vapor-liquid ratio, and evaporative emissions), ii) liquid split (e.g. water tolerance and enhanced solubility of aromatic fuel components in groundwater). Thus, the design of new biofuel blends requires tools able to predict final fuel properties.

Gasoline is a multicomponent mixture of mainly four families of hydrocarbons: normal-, branched- and cyclic-alkanes, together with aromatic hydrocarbons. Group contribution models are the best option to calculate the properties of mixtures containing a large number of similar compounds. In this case the number of required interaction parameters is dramatically reduced when compared with molecular models. In previous works, phase behavior of the family of normal-[2], branched-[3] and aromatic-[4] hydrocarbons in mixtures with water and alcohols were modeled with the group-contribution with association GCA-EoS equation of state. In the present work, the parameters required to include cycloalkanes have been determined.

The GCA-EoS attractive contribution to the Helmholtz energy is based on the surface interaction between groups. Similar to UNIFAC, GCA-EoS requires the knowledge of the van der Waals area of each functional group in order to quantify this interaction. All cyclic paraffins are represented in UNIFAC by a single CH2 group, having the same area (q) and volume (r) as the CH2 in normal-alkanes. The values of r and q parameters were obtained by normalizing Bondi´s[5] calculations, based on the structure/geometry of each functional group forming organic molecules. Cyclohexane has all its angles C-C-C, H-C-C and H-C-H very close to the ideal value for a tetrahedral configuration (109.5º). Hence, it is expected that the CH2 group in cyclohexane has the same r and q values as the regular CH2 in normal alkanes. However, other cycloalkanes have their tetrahedral ideal angle distorted and it is expected that they should have a different value of q and r per CH2 group. The corresponding q values were determined by vapor pressure fitting of some cycloalkanes. A very good representation of pure component vapor pressures was achieved (see figure 1). Moreover, binary and multicomponent mixtures were modeled. Figure 2 shows GCA-EoS predictive capacity to estimate alcohol and water in the quaternary system ethanol+water+cyclohexane+benzene.


Finally, the GCA-EoS predictive capacity to describe the effect of adding ethanol to different commercial gasolines was evaluated.

0

500

1000

1500

2000

2500

3000

3500

4000

200 300 400 500 600 700

T/K

P/kP

a

Figure 1: Vapor pressures of cycloalkanes. Experimental data DIPPR databank: () cyC3, (*)cyC5, ( ) methylcyC5, () cyC6, () t-1,2-dimethylcyC5, (+) methylcyC6, () cyC7, (∆) t-1,4-dimethylcyC6, (×) cyC8, () cyC10. Solid lines: GCA-EoS correlations. Dashed lines: GCA-EoS prediction.

Figure 2: Quaternary system ethanol (1) + water (2) + cyclohexane (3) + benzene (4) at 303 K and atmospheric pressure. Ethanol (full dots) and water (empty dots) partition coefficients (organic phase/aqueous phase) Lines: GCA-EoS prediction. C6H6/CyC6 weight ratio: (,) 0.245 and ( ,◊) 0.666

References [1] R. French, P. Malone, Fluid Phase Equilibria (2005), 228-229, 27-40. [2] T.M. Soria, F.A. Sánchez, S. Pereda, S.B. Bottini, Fluid Phase Equilibria (2010), 296, 116-124. [3] T.M. Soria, A. Andreatta, S. Pereda, S.B. Bottini, Fluid Phase Equilib. 2011, accepted for publication. [4] F.A. Sanchez, S. Pereda, E.A. Brignole, Fluid Phase Equilib. (2010), submitted for publication. [5] Bondi, A., Physical Properties of Molecular Crystals, Liquids and Glasses. John Wiley & Sons: New York, 1968.

0.001

0.010

0.100

1.000

0 0.2 0.4 0.6 0.8 1

x, water (Aqueus phase)

K

w, water in aqueous phase


A Molecular Based Osmotic Ensemble Monte Carlo Simulation Method for Free Energy Solvation Curves and the

Direct Calculation of Aqueous Electrolyte Solubility

Smith W.R.1, Moucka F.1,2, Lisal M.2,3

1 - Faculty of Science, Un. of Ontario Institute of Technology, Oshawa, Canada 2 - Physics Dept., J. E. Purkinje University, Usti n. Labem, Czech Republic

3 - E. Hala Laboratory of Thermodynamics, Inst. of Chemical Process Fundamentals, Prague, Czech Republic

[email protected]

We present a general methodology for Osmotic Ensemble Monte Carlo (OEMC) simulations for calculating free energy solvation curves and solubility of aqueous electrolytes, and apply it to alkali halides. The method performs simulations at a fixed number of water molecules, pressure, temperature and specified overall electrolyte chemical potential. Insertion/deletion of ions to/from the system is implemented using fractional ions, which are coupled to the system via a coupling parameter λ that varies between 0 (no interaction between the fractional ions and the other particles in the system) and 1 (full interaction between the fractional ions and the other particles of the system). Transitions between λ states are accepted with a probability following from the osmotic partition function. The method utilizes biasing weights associated with the λ states, in order to efficiently realize transitions between them. The biasing weights are determined by means of the Wang-Landau method. We also propose a scaling procedure for λ, which can be used for both non-polarisable and polarisable models of aqueous electrolyte systems. The scaling procedure conforms with the Generalized Reaction Field method, which we use for treatment of the long-ranged electrostatic interactions. The method is illustrated for a range of alkali halides, and the results compared with experiment.


Effect of polarization on the solubility of gases in molten salts

Simonin J.P.

Laboratoire PECSA, Paris, France

[email protected]

The solubility of noble gases and water in molten salts [1,2] is described by an analytical parameter-free description in terms of polarizable hard sphere (the gas particle) in a medium composed of charged hard spheres of comparable size (the salt). The chemical potential of solute contains contributions from excluded volume, polarization and dispersion forces [3]. The polarization of the gas particle is calculated explicitly within the framework of the mean spherical approximation for the ion-dipole mixture. An additional contribution originating from the polarization of the salt is proposed. This effect results from the breaking of symmetry about an ion caused by the presence of the solute particle in the vicinity of the ion (see Fig. 1). Its magnitude is estimated in an approximate way. This effect has been overlooked in previous theoretical studies.

++

E

−

+ −+

+

−

+−

−

GasC

Figure 1. Polarization of the salt induced by the presence of the gas particle.

The description is found to give good predictions for the solubility of noble gases and water in molten KCl and RbCl at 1173 K (see Fig. 2). The results suggest that volume exclusion and salt polarization may constitute the main two opposing factors affecting this phenomenon.


Figure 2. Result for the partition coefficient of noble gases in fused KCl and RbCl. Symbols: experimental values; Lines: theoretical result.

In the field of geosciences, this phenomenon may influence significantly the solubility of gases in molten silica [4].

References [1] A.L. Novozhilov and A. P. Khaimenov, Russ. J. Phys. Chem., (1976), 50, 1639-1641. [2] H.U. Woelk, Nukleonik, (1960), 2, 278-279. [3] S. Fukase, J. Phys. Chem., (1983), 87, 1768-1776. [4] P. Sarda and B. Guillot, Nature, (2005), 436, 95-98.

σBH (/Angströms)

2.5 3.0 3.5

-ln K

1

2

3

4

Ne

Ar

Kr

Xe

KCl

RbCl


Multicomponent Maxwell-Stefan Diffusivities at Infinite Dilution

Vlugt T.J.H.1, Liu X.1,2, Bardow A.1,2

1 - Delft University of Technology, Delft, The Netherlands 2 - RWTH Aachen University, Aachen, Germany

[email protected]

Diffusion plays a crucial role in (bio)chemical processes. It is usually difficult to obtain Maxwell-Stefan diffusivities from experiments as well as molecular simulation. Therefore, predictive models based on easily measurable quantities are highly desired. The Vignes equation is commonly used to describe the concentration dependence of Maxwell-Stefan diffusivities. In mixtures containing at least three components, the generalized Vignes equation requires the value of the quantity 1kx

ijĐ→ , which describes

the friction between components i and j when both are infinitely diluted in component k. Over the past decades, several empirical models were proposed for estimating 1kx

ijĐ→ ,

and all of these are lacking a sound theoretical basis [1]. We show that 1kxijĐ

→ actually exists, i.e. its value does not depend on the molar ratio xi/xj, and we derive an analytical expression for 1kx

ijĐ→ based on the linear response theory and the Onsager relations [2].

We find that 1kxijĐ

→ can be expressed in terms of self-diffusivities and integrals over velocity cross-correlation functions. By neglecting the latter terms, we obtain a convenient predictive model for 1kx

ijĐ→ in terms of self-diffusivities:

1 1

, ,1 1

, ,

1 11

k k

k k

x xself i self j

x xself k self k

k kk

x xx ik jkij

D DD D

Đ ĐĐ

→ →

→ →

→ →→ ≈ =

Molecular Dynamics simulations are used to validate the assumptions made in this model. The following test systems are considered: a ternary system consisting of particles interacting using Weeks-Chandler-Andersen (WCA) interactions and the ternary systems n-hexane-cyclohexane-toluene and ethanol-methanol-water. Our results show that: (1) for the WCA system as well as the system n-hexane-cyclohexane-toluene, neglecting the integrals over velocity cross-correlation functions results in accurate predictions for 1kx

ijĐ→ ; (2) for the WCA system, our model prediction is superior

compared to the existing models for 1kxijĐ

→ ; (3) in the ethanol-methanol-water system, the integrals over velocity cross-correlation functions cannot be neglected due to the


presence of hydrogen bonds. Models for predicting 1kxijĐ

→ in this system will require detailed information on the collective motion of molecules; (4) our model provides an explanation why the Maxwell-Stefan diffusivity between adsorbed components in a porous material is usually very large [3].

References [1] X. Liu, T.J.H. Vlugt, A. Bardow, Fluid Phase Equilibria, (2011), 301, 110-117. [2] X. Liu, A. Bardow, T.J.H. Vlugt, Ind. Eng. Chem. Res., (2011), submitted. [3] R. Krishna, J.M. van Baten, Chem. Eng. Sci., (2009), 64, 870-882.


Modeling of electrolyte solutions with COSMO-RS

Ingram T., Gerlach T., Mehling T., Smirnova I.

Hamburg University of Technology, Institute of Thermal Separation Processes, Eißendorfer Str. 38, 21073 Hamburg, Germany

[email protected]

Electrolytes have a pronounced effect on phase equilibria of natural systems like waste water, biological systems as well as on chemical and pharmaceutical processes. A reliable knowledge of phase equilibria in presence of electrolytes is essential for the design and simulation of different chemical processes.

The thermodynamic model COSMO-RS has proven its applicability for molecular systems. In addition the model COSMO-RS has shown to yield good qualitative and satisfying quantitative predictions for many charged molecules like ionic liquids and ionic surfactants [1]. However presently the model COSMO-RS cannot account for long range interactions which have a pronounce effect on solutions containing monatomic electrolytes like (Na+, Li+ or K+). Therefore the element specific cavity radii of alkali metals in COSMO-RS are currently not optimized [2].

Excess Gibbs energy models like NRTL, UNIQUAC and UNIFAC, which describe short range interactions, have successfully been extended to electrolyte solutions by adding a long range contribution.

exG = ex

SRG + exLRG

The long range contributions are generally described based on a Debye-Hückel-model, or the mean spherical approximation (MSA). Both models accurately describe long range interactions of ions in dilute electrolyte solutions.

In order to predict phase equilibria of systems containing monatomic electrolytes with COSMO-RS the model has been extended for solutions containing corresponding salts. The element specific COSMO-radii of the alkali metals Li, Na, K, Rb, and Cs have been optimized under consideration of long range interactions. Both the unsymmetric Pitzer–Debye–Hückel (PDH) equation and a MSR term were evaluated. The results demonstrate that the broad physical fundament of the model COSMO-RS must be extended for segments containing large surface charge densities like monatomic ions.

Therefore a Lewis acid contribution was implemented for cations and new element specific parameter were fitted based on experimentally determined mean ionic activity coefficients (MIAC) in aqueous solutions.


This extension of COSMO-RS is evaluated based on predicted MIACs in mixed solvents, vapor pressures of electrolyte solutions, Setschenow constants and liquid-liquid equilibria of aqueous electrolyte solutions / organic solvent. It can be concluded that based on a profound physical assumptions COSMO-RS is able to predict phase equilibria in presence of strong electrolytes.

References [1] Mokrushina, L.; Buggert, M.; Smirnova, I.; Arlt, W.; Schomäcker, R. (2007):

COSMO-RS and UNIFAC in Prediction of Micelle/Water Partition Coefficients. In: Industrial & Engineering Chemistry Research, Jg. 46, H. 20, S. 6501–6509.

[2] Klamt, A.; Eckert, F.; Arlt, W. (2010): COSMO-RS: An Alternative to Simulation for Calculating Thermodynamic Properties of Liquid Mixtures. In: Annual Review of Chemical and Biomolecular Engineering, Jg. 1, H. 1, S. 101–122.


Liquid Water: A State Between Two Critical Points

Anisimov M.A.1,2

1 - Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA

2 - Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742, USA

[email protected]

Liquid water is still a puzzle. Unlike ordinary substances, one can regard water near the triple point and in supercooled region, on the one side, and near the vapor-liquid critical point, on the other side, as “the same substance – two different liquids”. Some of the puzzles of liquid water can be explained by the existence of the liquid-liquid critical point in metastable supercooled region. Fluctuations of water structure, diverging at the liquid-liquid critical point, may be associated with anomalous sensitivity (“susceptibility”) of water structure to external perturbations and may also be responsible for mysterious behavior of some nonelectrolyte aqueous solutions.

Invited Lecture


Solubility of K2SO4 in Supercritical Water using Monte Carlo Method

Dávila J., Moncada M., Caceres J.

Universidad de los Andes, Bogotá, Colombia

[email protected]

In the production of Ethanol, the vinasse is the most important wastewater in these industries, the vinasse has a significant content in salts and the most representative salt is K2SO4. The Supercritical Water Oxidation (SCWO) is an alternative to treat this kind of wastewater to reach a higher conversion of the organic material but, some of the problems in the SCWO processes are the corrosion and the salt deposition [1, 2, 3]; in the case of the corrosion is possible to use reactors with special materials that support the corrosion, but in the case of the salt depositions is important to know the solubility of the salts at the conditions of operation.

In this way, we obtained the solubility of the K2SO4 between 645 K and 735 K of the temperature and 31 MPa of pressure using a Monte Carlo (MC) method to obtain the molecular interaction properties using the insertion method of Widom (WIM) as follows [4, 5]:

2 2 2 22

1

expsat s sat r

B B

P v (P P ) µy =

ρ k T RT k T

− −

The Peng – Robinson equation of state was used to obtain the density of supercritical water and the Lenard Jones potential was used together with the NVT canonical ensemble. Both, the supercritical water and K2SO4 were treated as single site molecules for simplification.

The figure 1(a) shows the residual chemical potential of K2SO4 to 100 particles of supercritical fluid as a function of temperature and the figure 1(b) shows the mol fraction of K2SO4 as a function of temperature.

The molar fraction is similar to the solubility reported by Hodes et al. [6], in which the solubility was calculated at 25 MPa. In this way, the solubility of K2SO4 calculated using the Monte Carlo method is in agreement with the experimental data reported by Hodes.


Figure 1. (a) Residual Chemical Potential as a function of the temperature to 100 particles and (b) Molar fraction of K2SO4 as a function of the temperature. References [1] K. Kríkopský, B. Wellig and Ph Rudolf von Rohr. SCWO of salt containing artificial wastewater using a transpiring-wall reactor. Experimental results. J. of Supercritical Fluids., vol 40, pages 246–257, year (2007). [2] P. Kritzer and E. Dinjus. An assessment of supercritical water oxidation (SCWO) Existing problems, possible solutions and new reactor concepts. Chem. Eng. Journal., vol 83, pages 207–214, year (2001). [3] D. McDonald and B. Kriksunov. Probing the chemical and electrochemical properties of SCWO systems. Electrochemica Acta., vol 47, pages 775–790, year (2001). [4] Y. Iwai, H. Uchida, Y. Koga and Y. Arai. Monte Carlo Simulation of Solubilities of Aromatic Compounds in Supercritical Carbon Dioxide by a Group Contribution Site Model. Ind. Eng. Chem. Res., vol 35, pages 3782–3787, year (1996). [5] Y. Iwai, H. Uchida, Y. Mori and Y. Arai. Monte Carlo simulation of solubilities of naphthalene, phenanthrene, and anthracene in supercritical fluids. Fluid Phase Equilibria., vol 144, pages 233–244, year (1998). [6] M. Hodes, P. Griffith, K. Smith, W. Hurst, W. Bowers, K. Sako. Salt Solubility and Deposition in High Temperature and Pressure Aqueous Solutions. AIChE Journal., vol 50, No 9, pages 2038–2049, year (2004).



SESSION 3: Ionic Liquids


Measurements and equation-of-state modeling of liquid-liquid phase equilibria in binary systems containing a piperidinium

ionic liquid

Paduszyński K., Domańska-Żelazna U.M.

Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, POLAND

[email protected]

For the design of more efficient and “greener” processes with ionic liquids (ILs) (e.g. liquid-liquid extraction) obtaining reliable thermodynamic data on systems containing them, is of great importance. Moreover, detailed knowledge of phase behavior of ILs and their mixtures with various organic and inorganic solvents is always needed to understand the nature of molecular interactions and enables the development of thermodynamic models, e.g. equations of state.

Present contribution concerns with thermodynamic study of liquid-liquid equilibrium (LLE) in binary systems containing piperdinium cation-based ionic liquid, namely 1-methyl-1-propylpiperidinium bis(trifluoromethylsulfonyl)imide (abbreviated by [MPPIP][NTf2]) and 1-alkanol or aliphatic hydrocarbon.

The work consists of two parts. Within the first part new experimental data of binary LLE obtained by synthetic method are presented and the influence of both solutes’ structure on the phase behavior is discussed. The second part includes a modeling of the reported phase equilibrium data in terms of two modern EOSs: lattice fluid theory-based NRHB EOS and perturbation theory-based PC-SAFT EOS. In the case of both models electrostatic interactions are treated as a contribution to strong specific interactions [1]. Pure-fluid parameters for [MPPIP][NTf2] were determined from liquid density temperature dependence and solubility parameters obtained from infinite dilution activity coefficients (γ∞) of different solutes in the ionic liquid [2]. Both EOSs are capable to describe those data in wide temperature range with average absolute relative deviation less than 0.2%. The LLE phase diagrams were calculated by using standard mixing rules and temperature dependent binary interaction parameters obtained by fitting the γ∞ or LLE data to models’ predictions.

References [1] C. Tsioptsias, I. Tsivintzelis and C. Panayiotou, Phys. Chem. Chem. Phys, (2010), 12, 4843-4851. [2] U. Domańska and K. Paduszyński, J. Chem. Thermodyn., (2010), 42, 1361-1366.


How ionic liquid changes properties of dense membrane in pervaporation separation process?

Kacirkovák M.1, Randová A.2, Hovorka S.2, Schauer J.3, Tisma M.4, Izák P.1

1 - Institute of Chemical Process Fundamentals, Academy of Sciences of Czech Republic 2 - Institute of Chemical Technology in Prague, Czech Republic

3 - Institute of Macromolecular Chemistry, Academy of Sciences CR 4 - Faculty of Food Technology Osijek, University of Osijek, Croatia

[email protected]

Pervaporation was used for the removal of butan-1-ol from its 5 wt. % aqueous solution at which concentration Clostridium acetobutylicum fermentation slows down. Two types of membranes were used: a polydimethylsiloxane (PDMS) membrane containing 0, 10, 20 or 30 wt. % of ionic liquid benzyl-3-butylimidazolium tetrafluoroborate ([BBIM][BF4]) and a polyethylene (PE) membrane in which [BBIM][BF4] was sandwiched between two PE films. Differential scanning calorimetry measurements showed that PDMS and [BBIM][BF4] are not compatible and although optically homogeneous, PDMS-[BBIM][BF4] membranes contained PDMS and [BBIM][BF4] phases. Pervaporation selectivity increased and the total flux through the membrane moderately raised with the increased content of [BBIM][BF4] in the PDMS-[BBIM][BF4] membranes. Hence, the immobilization of a proper ionic liquid in the membrane could be the good method for removal the alcohol from fermentation broths by pervaporation. On the contrary, [BBIM][BF4] layer sandwiched between two PE films had no practical effect on the pervaporation properties.

To get more effective aceton, butan-1-ol, ethanol removal we prepared the IL-PDMS membrane. This membrane showed high stability and also selectivity during all measurements with real fermentation broth with living microorganisms. We were able to remove more butan-1-ol and acetone than the C. acetobutylicum was able to produce. To prove the effectiveness of our set up we ran the fermentation reaction on the limiting values of butan-1-ol concentration (18 g/L) to see, if under these conditions the bacteria could still be alive. We proved experimentally that this concentration was already deadly for the bacteria. If we would run pervaporation with continuous removal of butan-1-ol, C. acetobutylicum would survive and could produce even more BIObutanol.

Acknowledgements This work was supported by the Czech Science Foundation (104/08/0600).


Phase Behavior and Thermodynamic Properties of the Binary Systems Quinolinium, or Isoquinolinium-Based Ionic Liquids

+ Hydrocarbon, or + an Alcohol

Domańska-Żelazna U.M., Zawadzki M.

Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland

[email protected]

New ionic liquids, N-butylquinolinium, or N-hexylquinolinium, or N-octylquinolinium bis(trifluoromethyl)sulfonylimide, [BQuin][NTf2] [1], [HQuin][NTf2] [2], [C8Quin][NTf2], or N-butylisoquinolinium, or N-hexylisoquinolinium, or N-octylisoquinolinium bis(trifluoromethyl)sulfonylimide, [BiQuin][NTf2], [HiQuin][NTf2], [C8iQuin][NTf2][3], have been synthesised from bromides. Specific basic characterization of the synthesized compounds, which includes NMR spectra, elementary analysis, and water content is presented. The basic thermal properties of the pure ILs, i.e. melting and solid-solid transition temperatures, as well as the enthalpy of fusion, or solid-solid transition have been measured using a differential scanning microcalorimetry technique (DSC). The temperature-composition phase diagrams of binary mixtures composed of the ionic liquid IL + an aromatic hydrocarbon, or an alcohol have been determined from ambient temperature to the boiling point temperature of the solvent at ambient pressure. A dynamic method was used over a broad range of mole fractions and temperatures from 270 to 330 K. For the binary systems the eutectic diagrams were observed with immiscibility in the liquid phase with an upper critical solution temperature (UCST). In the case of the mixture IL + benzene, or alkylbenzene the eutectic systems with mutual immiscibility in the liquid phase with very high UCSTs were observed. For mixtures with alcohols it was observed that with an increasing chain length of the alcohol the solubility decreases and the UCST increases. The complete miscibility in the liquid phase was observed for short chain length of an alcohol (1-butanol, 1-hexanol) and immiscibility with UCST in the liquid phase for the remaining alcohols. The coexistence curves corresponding to liquid-liquid phase equilibria (LLE) boundaries and the solid-liquid phase equilibria have been correlated using the well-known NRTL model. Densities and viscosities were determined as a function of temperature.

[HQuin][NTf2], with low viscosity, low density, high heat capacity at solid and liquid phase, high enthalpy of melting and low melting temperature was proposed for possible use in the phase change materials (PCM).

The activity coefficients at infinite dilution, 13γ∞ for 37 solutes: alkanes, alkenes,

alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, ethers, ketones and water in the [C8iQuin][NTf2] were determined by gas-liquid chromatography at the temperatures


from (328.15 to 368.15) K. The partial molar excess enthalpies at infinite dilution values E,

1∆H ∞ were calculated from the experimental 13γ∞ , obtained over the temperature

range. The selectivity for the n-hexane/benzene, cyclohexane/benzene and n-heptane/thiophene separation problems were calculated from the 13γ

∞ and compared to the other ionic liquids with bis(trifluoromethyl)sulfonylimide anion, NMP and sulfolane, taken from the recent literature. The chosen ionic liquid demonstrates that it is possible to separate different organic compounds with the average selectivity and capacity.

References [1] U. Domańska, M. Zawadzki, M.M. Tshibangu, D. Ramjugernath, T.M. Letcher, J. Chem.Thermodyn. 42 (2010) 1180-1186. [2] U. Domańska, M. Zawadzki, M. Zwolińska, J. Chem. Thermodyn. (2011) in press. [3] U. Domańska, M. Zawadzki, M. Królikowska, M.M. Tshibangu, D. Ramjugernath, T.M. Letcher, J. Chem.Thermodyn. 43 (2011) 499-504.


Imidazolium ionic liquids as amphiphilic additives in solutions

Safonova E.A., Koneva A.S., Smirnova N.A.

Department of Chemistry, Saint-Petersburg State University, Saint-Petersburg, RUSSIA

[email protected]

Many ILs are amphiphilic substances with pronounced hydrophilic and lipophilic molecular fragments, and this determines their surface activity and the ability to self-organize in the individual state and in solutions. Micellization in solutions of ILs is studied extensively since 2004 (see e.g. review [1]). Most of the studies deal with aqueous solutions of 1-alkyl-3-methylimidazolium salts [Cnmim]X, where anion X is usually Br−, Cl−, BF4

− or PF6− and the number of carbon atoms in the alkyl chain varies

from 2 to 16. The results permit to conclude that [Cnmim]X salts behave like typical cationic surfactants. Their aggregation behavior is similar to that of alkyltrimethylammonium salts (CnTAX) but the cmc values for [Cnmim]X salts are somewhat lower than for CnTAX with the same n value. Disc-like shape and distinct polarizability of imidazolium head groups, the ability to hydrogen bonding are responsible for some specific features of ordering in systems containing imidazolium ILs. Self-organization phenomena open additional perspectives for applications of ILs in chemical synthesis, catalysis, electrochemistry, extraction and chromatography, in micellar electrokinetic capillary chromatography, in the synthesis of polymer materials, nanomaterials etc.

In this work we discuss new and obtained previously [2,3] results of the following studies performed in our laboratory:

- [Cnmim]X as modulators of aggregation in aqueous solutions of sodium dodecylsulfate NaDS [2,3]; effect of additions of [C4mim]PF6 , [C6mim]X (X = Br, Cl, BF4) and [C10mim]Br was under consideration;

- molecular-thermodynamic modeling of micellization in [Cnmim]X and [Cnmim]X-NaDS aqueous solutions [2];

- properties of aqueous dispersions of carbon nanotubes prepared using a number of ILs [Cnmim]X and their mixtures with NaDS as amphiphilic additives.

Critical micelle NaDS concentrations (cmcNaDS) were determined applying conductivity measurements, potentiometry, nuclear magnetic resonance and titration calorimetry. The enthalpy of micellization was also measured. The studies have shown that alkylimidazolium ILs are effective modulators of micellization in NaDS solutions, a significant cmc decrease being attained already at very low IL concentrations. ILs act more effectively than inorganic salts due to the combination of the electrostatic cation-anion interactions with the hydrophobic effect and the formation of mixed micelles; the IL effect grows with the increase of the alkyl chain length. The cmc dependence on the


relative mole fraction x’IL of IL in NaDS–[C10mim]Br solutions is typical of mixtures of anionic and cationic surfactants: the cmc decreases sharply on small additions of one component to the other, whereas over the wide range of x’IL values (~0.1-0.9) the cmc changes are insignificant. Thermodynamic characteristics of micellization for equimolar NaDS-IL solutions were calculated applying the pseudophase separation model.

Calculations of the cmc, the aggregation number and the composition of mixed micelles were performed using the version of the quasi-chemical aggregation model by Nagarajan and Ruckenstein. In [2] this approach was applied to solutions of ILs for the first time. The calculated cmc values for [Cnmim]Br homologues (8 < n < 16) agree satisfactorily with the experimental data although at n = 8 and 10 the predicted values are somewhat too high. In the case of n = 4, 6 both the experimental data and the model calculations give no cmc for IL in aqueous solution. The model reproduces in main features the effect of small additions of IL with different chain length on the cmcNаDS but there are significant discrepancies between the experimental and calculated values in the case of short-chained ILs. The model can be useful for predictions of aggregative behavior in the case of long-chain ILs and their mixtures with classical surfactants.

It has been shown recently that long-chain imidazolium ILs can be effectively used as surfactants to disaggregate single-walled carbon nanotubes and to obtain their stable dispersions [4], this being a perspective field of ILs application. In our study C12mimCl and [Cnmim]X - NaDS mixtures were used as additives. Various compositions of mixtures, several regimes of ultrasonification and centrifugation were tested; stability and other characteristics of the dispersions obtained were investigated.

Financial support from RFBR (projects 09-03-00746-а, 11-03-01106-а) and St.Petersburg State University (grants 12.0.21.2007, 12.37.127.2011) is acknowledged.

References [1] Łuczak J., Hupka J., Thöming J., Jungnickel C., Colloids and Surfaces A: Physicochem. Eng. Aspects, (2008), 329, 125-133. [2] Smirnova N.A., Vanin A.A., Safonova E.A. et al., J. Coll. Interf. Sci., (2009), 336, 793-802. [3] Smirnova N.A., Safonova E.A., Russian J. Phys. Chem. A, (2010), 84, 1695-1704. [4] A.Di Crescenzo, D. Demurtas, A.Renzetti et al., Soft Matter, (2009), 5, 62-66.


Solubility of cinnamic acid derivatives in ionic liquids: experimental measurements and thermodynamic modeling

Alevizou E., Voutsas E.

School of Chemical Engineering, National Technical University of Athens, Greece

[email protected]

Ionic liquids (ILs) steadily gain wide recognition as environmentally benign alternatives of volatile organic solvents in a variety of physical and chemical processes. ILs are molten salts or molten oxides with melting points below 100o C. Moreover, they are often in the liquid state at ambient or even lower temperatures, referred to as Room-Temperature ILs (RTILs).1 Compared to conventional organic solvents, the use of ILs for synthesis and separation processes has a number of advantages due to the unique combination of their properties. These liquids have negligible vapor pressure, a liquid range of more than 400K, high thermal stability, high electrical conductivity, and density being greater than that of water. ILs are miscible with substances having very wide range of polarities and can simultaneously dissolve organic and inorganic substances. These features of RTILs offer numerous opportunities for modification of existing and for the development of new extraction processes. In some cases, such processes would be impossible with conventional solvents because of their limited liquid range or miscibility. The novel feature of RTILs as solvents is the possibility to design one IL with the necessary properties for a specific application, hence the term “designer solvents”. The choice of base cation and anion creates the major properties of a particular RTIL, with fine tuning of its properties to be possible by the variation of the length and branching of the alkyl groups incorporated into the cation.2

The cinnamic acid derivatives (CADs) belong to the family of phenolic acids. They are natural hydrophilic antioxidants, which occur ubiquitously in fruits, vegetables, spices, and aromatic herbs. They are of particular interest because of their potential chemical and biological properties, such as antioxidant, chelating, free radical scavenging, anti-inflammatory, antiallergic, antimicrobial, antiviral, anticarcinogenic, as well as UV filter properties. They can be used as raw materials for the synthesis of different molecules with industrial interest, such as drugs, cosmetics, antiseptics, and flavors; they also can be used in the preparation of resins, plasticizers, dyes, inks, and pharmaceutical products.3,4

A prerequisite for the synthesis and design of chemical and separation processes is the reliable knowledge of the phase equilibrium behaviour of the systems involved. For example, for the crystallization process the solid-liquid equilibrium (SLE), i.e. solubility of solids in the liquid phase, has to be known. Also, for reaction design the knowledge of the phase equilibrium, i.e. activity coefficients of the reactants and products in the solution, is of major importance.


This work focuses on the solubilities of two CADs, namely, p-coumaric acid and caffeic acid. Solubilities of these compounds have been measured in six imidazolium based ILs, namely, 1-butyl-3-methyl imidazolium hexafluorophosphate, 1-octyl-3-methyl imidazolium hexafluorophosphate, 1-butyl-3-methyl imidazolium tetrafluoroborate, 1-octyl-3-methyl imidazolium tetrafluoroborate, 1-butyl-3-methyl imidazolium bis(trifluoromethanesulfonyl)imide and 1-butyl-3-methyl imidazolium trifluoromethanesulfonate in the temperature range of 30 oC to 50oC. The influence of the different anion, the length of the alkyl groups incorporated into the cation, the polarity and the hydrogen bonding to the solubility is studied. Finally, the experimental solubility data have been correlated with the NRTL and UNIQUAC equations, while the accuracy of the COSMO-RS model in the prediction of the solubilities of CADs in ILs is evaluated.

References 1. Seddon, K. R. Ionic Liquids for Clean Technology. J. Chem. Tech. Biotechnol. 1997, 68 (4), 351. 2. Marsh, K.N.; Boxall, J.A.; Lichtenthaler, R. Room Temperature Ionic Liquids and their Mixtures - A Review. Fluid Phase Equilib. 2004, 219 (1), 93. 3. Fatima L. Mota, Antonio J. Queimada, Simao P. Pinho, and Eugenia A. Macedo, Aqueous Solubility of Some Natural Phenolic Compounds, Ind. Eng. Chem. Res 2008, 47, 5182-5189. 4. Maria-Cruz Figueroa and Pierre Villeneuve, Phenolic Acids Enzymatic Lipophilization, J. Agric. Food Chem., 2005, 53, 2779-2787.


Treble calorimetry: an elegant access to vaporization enthalpies of ionic liquids by DSC, solution, and combustion

calorimetry

Verevkin S.P.1, Emel'yanenko V.N.1, Ralys R.1, Zaitsau Dz.H.1, Heintz A.1, Schick C.2

1 - Chemical Department, University of Rostock, Dr-Lorenz-Weg 1, 18059 Rostock, Germany 2 - Department of Physics, University of Rostock, Rostock,Wissmarsche Str. 43-45, 18057

Rostock Germany

[email protected]

Ionic liquids (ILs) are commonly defined as organic salts with unusually low melting points and practically negligible vapour pressure. In this context, is there any common sense to learn something about ILs in the gaseous state? Yes, indeed! Study of the thermodynamic properties of IL according to the general relation

∆f mH° (g) = ∆f mH° (liq) + mgl H∆ (1),

remains crucial to an understanding of the nature, behaviour, and interactions of this fluids. To date, there are only a few experimental studies of vapor pressures and vaporization enthalpies, m

gl H∆ , of ILs. Experimental studies are time-consuming and

they are confronted with two main problems. At room temperature the low vapor pressures of ILs are practically not measurable, whereas at high temperatures some of them may begin to decompose. Following, a rapid progress towards to extend experimental data set on m

gl H∆ of ILs is hardly to be expected. Is there any

compromise solution?

Let us “turn that frown upside down” and reorganize the general eq 1 as follows:

mgl H∆ = ∆f mH° (g) − ∆f mH° (liq) (2)

It seems to be not particularly rational to consider the vaporisation process “upside down”, namely from the hypothetical (and not directly measurable) gaseous state back to the condensed state of the pure liquid! Anyway, provided that ∆f mH° (g) and

∆f mH° (liq) are available from another methods, the mgl H∆ , could be easily obtained

using eq 2 for any IL of interest! We have shown that ∆f mH° (g) could be reliable calculated by one of the suitable composite first-principles method. We have explored an alternative possibility to measure ∆f mH° (liq) with help of DSC. This approach has four advantages: the requirement of relatively small amounts of sample, less rigorous purity requirements, short actual experimental times, and the simplicity and


accessibility of the experimental setup. Enthalpy of vaporization of [BMIM][Br] obtained in this work using DSC and G3MP2 was in good agreement with the available experimental value derived from Knudsen-Quartz-Microbalance technique. Another valuable thermochemical option to derive ∆f mH° (liq or cr) of ionic liquids is using a combination of the experimental results from combustion calorimetry and from the solution calorimetry.

Thus, we have developed a valuable procedure to obtain vaporization enthalpies of ILs using a combination of the DSC, solution and combustion calorimetry with the high-level ab initio calculations according to eq 2. Such a procedure has opened a new avenue for the rapid accumulation of vaporization enthalpies for ILs.


High-Pressure Densities of Ionic Liquids: Structure-Property Relations and New Measurements

Regueira T.1, Lugo L.1,2, Fernández J.1

1 - Laboratorio de Propiedades Termofisicas, Universidade de Santiago de Compostela, E-15782 Santiago de Compostela, Spain

2 - Current address: Departamento de Física Aplicada, Facultade de Ciencias, Universidade de Vigo, E-36310 Vigo, Spain

[email protected]

Ionic liquids (ILs) have been investigated over the last decade for different applications, as lubricants and lubricant additives as well as in biorefining, biotechnology, chemicals and petrochemicals, CO2-capture, environmental remediation, pharmaceuticals and waste treatment. To develop some of these applications thermophysical properties in broad ranges of temperature and pressure are needed. ILs possess many advantages that make them ideal candidates for these applications being one of the more important their “structural tuneability” that permits that several of their properties can be easily tuned through an adequate combination of cation and anion. For this aim it is needed to know the structure-property relations. Thus, the choice of the cation and the anion of the ILs, as well as the ion side chain design, determine their fundamental properties. In this work, we analyze the trends, with the cation and the anion, of density, viscosity and their dependence with temperature and pressure as well as degradation, melting, thermo-oxidation and glass transition temperatures which are important in several applications, such as their use in lubrication [1]. Moreover, PVT values are fundamental data for developing equations of state and solution theories, which are the main tool used for thermophysical properties prediction for process design purposes. Aparicio et al. [2] have recently analyzed the density data at high pressures for liquids available in the open literature. A high number of density data at high pressures correspond to ILs with tetrafluoroborate and hexafluorophosphate anions which are not very reliable for industrial applications. Data for new or environmentally friendly ionic liquids are almost absent [2]. In this work, we have performed density measurements of four ILs, 1-ethyl-3-methylimidazolium ethylsulfate, [C2C1Im][C2SO4], 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, [C4C1Pyrr][NTf2], 1-(2-Methoxyethyl)-1-methyl-pyrrolidinium tris(penta-fluoroethyl) trifluorophosphate, [C1OC2C1Pyrr][(C2F5)3PF3] and 1-(2-Methoxyethyl)-1-methylpyrro-lidinium bis(trifluoromethylsulfonyl)imide [C1OC2C1Pyrr][NTf2]. Density measurements were performed from 278.15 K to 398.15 K and pressures up to 120 MPa, using a fully automated vibrating tube densimeter Anton Paar HPM [3,4]. We should point out that we have not found in the literature density data at high pressures for ILs containing the cation [C1OC2C1Pyrr]+ and neither with the anion [(C2F5)3PF3]- . The ILs samples used in this work were provided by Merck with purity >98%. The samples were treated by vacuum evaporation to remove the residual volatile impurities.


Their water content was determined with Karl Fischer titration. Density values were correlated as a function of pressure and temperature with the modified Tamman-Tait equation with standard deviations lower than 3·10-4 g·cm-3. We have found the following sequence for the experimental densities: [C1OC2C1Pyrr]+[(C2F5)3PF3]- > [C1OC2C1Pyrr]+[NTf2]- > [C4C1Pyrr]+[NTf2]- > [C2C1Im]+ [C2SO4]-. It can be concluded that the ILs with the anion [(C2F5)3PF3]- present higher density than the ILs with the [NTf2]- anion. We have applied the method proposed by Gardas and Coutinho [5,6] for predicting compressed densities of the ILs in the temperature range from 278.15 to 398.15 K and up to 120 MPa obtaining and AAD lower than 1.5%. We have also determined the isothermal compressibilities from the Tamman-Tait correlations obtaining the following trend [C1OC2C1Pyrr]+[(C2F5)3PF3]- > [C4C1Pyrr]+[NTf2]- > [C1OC2C1Pyrr]+[NTf2]- > [C2C1Im]+ [C2SO4]-. The effect of the anion, cation and alkyl chains on the compressibilities will be analyzed for these ILs and for those for which there are literature data [2] as well as the effect of the molecular weight of the anion. Furthermore, we will also analyze the pressure effect on the unusual behaviour [7] of the isobaric thermal expansivity, (the decreasing value of αP with increasing temperature). In addition, we will extend the previous analysis [5, 6, 8] on the structure-density relations, i.e. the effect on the densities of functionalization of the chain with hydrophilic groups, the head group of the cation and of the molecular weight of the anion, for the new ILs studied here. Authors acknowledge Dr. Uerdingen from Merck for his excellent advice and the samples provided. This work was supported by Spanish Ministry of Science and Innovation and EU FEDER Program through CTQ2008-06498-C02-01 project. T.R. acknowledges financial support under the FPU program. L.L. acknowledges the financial support of the Ramon y Cajal Program.

References 1. A.S. Pensado, M.J.P. Comuñas, J. Fernández, Tribol. Lett. 2008, 31, 107-118. 2. S. Aparicio, M. Atilhan, F. Karadas, Ind. Eng. Chem. Res. 2010, 49, 9580–9595. 3. J. J. Segovia, O. Fandiño, E. R. López, L. Lugo, M. C. Martín, J. Fernández, J. Chem. Thermodyn. 2009, 41, 632-638. 4. O. Fandiño, E. R. López, L. Lugo, J. Fernández, Fluid Phase Equilib. 2010, 296, 30-36 5. R. L. Gardas and J. A. P. Coutinho, Fluid Phase Equilib., 2008, 263, 26-32. 6. J.A.P. Coutinho, R.L. Gardas "Predictive Group Contribution Models for the Thermophysical Properties of Ionic Liquids" in Ionic Liquids: From Knowledge to Application ed. N.V. Plechkova, R.D. Rogers, K.R. Seddon (2009) ACS Symp Series 1030, Chapter 5, 385-401. 7. J. Troncoso, C.A. Cerdeiriña, P. Navia, Y.A. Sanmamed, D. González, L. Romaní, J. Phys. Chem. Lett. 2010, 1, 211. 8. C. Kolbeck, J. Lehmann, K. R. J. Lovelock, T. Cremer, N. Paape, P. Wasserscheid, A. P. Fröba, F. Maier, H.-P. Steinrück, J. Phys. Chem. B, 2010, 114, 17025–17036.



SESSION 4: Surfactants, Polymers and Bio-Related Systems


Sorption equilibria and diffusion dynamics in semi-crystalline polymers

Kosek J., Hájová H., Pokorný R., Chmelař J., Nistor A.

Institute of Chemical Technology, Prague, Czech Republic

[email protected]

Understanding of sorption equilibria and transport processes in polymers is of significant importance in the design of polymerization plants. This contribution focuses on several possibilities to study these phenomena. The sorption of low molecular species (penetrants) in polyolefins was studied experimentally on a gravimetrical apparatus and a pressure-decay apparatus. The obtained solubilities were compared to the results obtained by the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state. In the case of a purely amorphous polymer one can obtain good agreement between the experimental data and PC-SAFT calculations only by using appropriate binary interaction parameters. This is however not possible in the case of semi-crystalline polymers due to the presence of elastic constraints exerted by the crystalline phase on the amorphous domains, in which the sorption takes place. Elastic contribution to the chemical potential and pressure were thus introduced into the PC-SAFT model together with an additional parameter - the fraction of elastically affected chains. This improved model was in good agreement with our experimental data. Our ultimate target in this field is the creation of correlations between the adjustable model parameters, temperature and physical properties of the sample (e.g., crystallinity) in order to enable reliable prediction of solubilities.

Figure 1: Scheme of the elastic constraining effect in semi-crystalline polymers.

Elastically effective chain

r r

cryst.lamella

cryst.lamella

amorphousphase

Another important issue regarding sorption in polymers are the “co-solvent” and “anti-solvent” effects (also called sorption enhancement and inhibition, respectively). In order to study these effects, cosorption equilibria were measured on the gravimetrical apparatus and the results were used to validate the PC-SAFT model for multi-component systems. The “co-solvent” and “anti-solvent” effects were then studied mainly on the PC-SAFT predictions, as only total solubilities are accessible by our experimental techniques.


Figure 2: Comparison of the solubility in the ternary system with the solubilities in the binary systems and the ternary system prediction based on the binary data.

Cosorption of ethylene and 1-hexene in PE

0.00

0.02

0.04

0.06

0.08

0.10

0 10 20 30p(bar)

Solu

bilit

y (g

/gam

,PE)

Pure ethylene

Pure hexene

Cosorption

Sum of binary

The diffusion of penetrants in polymers was studied experimentally on the same apparatus as sorption. Activated diffusion following the Arrhenius equation for the diffusion coefficient (D) was observed for the diffusion of ethylene and propane in polyethylene (PE) at temperatures below the melting point, whilst only weak dependency of D on temperature was observed in the melt. Very steep dependency of D on temperature is observed around the melting point. The comparison of D in the melt and in the semi-crystalline phase enables us to estimate the tortuosity of the amorphous phase in the semi-crystalline sample. We suggest that the tortuosity has a “classical” geometrical contribution and an activated diffusion contribution, which is temperature dependent. We have compared these results with predictions obtained from a mathematical model of diffusion in reconstructed semi-crystalline spherulites. Diffusion is then modeled in these spherulites, which enables the correlation of the diffusion properties with the semi-crystalline morphology.

Figure 3. a) left: scheme of the reconstructed spherulitic structure; b) right: comparison of the

experimental result with model predictions for spherulites (S) and fringed micelles (M).

References [1] Banaszak, B. J.; Novak, A.; Kosek, J. et al., Macromolecules, 2004 [2] Novak, A.; Bobak, M.; Kosek, J. et al., J. Appl. Polym. Sci., 2006 [3] Bobak, M., Gregor, T., Kosek, J. et al., Macromol. React. Eng., 2008


Phase Equilibria of Surfactant Containing Systems

Schrader P., Kulaguin – Chicaroux A., Dorn U., Enders S.

TU Berlin, Germany

[email protected]

Hydroformylation, also known as oxo synthesis, is an important industrial process for the production of aldehydes from alkenes, because the resulting aldehydes are easily converted into many secondary products. The hydroformylation of alkenes with a low carbon number using a hydrophilic rhodium catalyst is one of the most important chemical reactions in the chemical industry [1]. However; the use of the hydroformylation for the production of long-chain aldehydes causes several problems, for instance the extreme low solubility of the educts in a hydrophilic environment, and is in the moment not applicable in industrial scale. Haubach et al. [2] succeeded the preparation of long chain aldehydes (i.e. C13) from long-chain alkenes (C12) hydroformylation applying a rhodium catalyst can be used in the laboratory. Caused by the very limited water solubility of C12 alkenes, the chemical reaction can be performed using a microemulsion forming system [w]. The microemulsion can be prepared from non-ionic surfactant, water and oil.

The knowledge of the complex phase behavior of this system is an essential condition. The ternary phase behavior is depicted in Figure 1. The essential feature of this phase behavior is the so-called “Kahlweit fish” appearing at a constant water-oil ratio as function of temperature. In this contribution we focus our attention to the phase diagrams of the ternary and the corresponding binary sub-systems (water + oil, surfactant + oil, surfactant + water). For the experimental studies octa-oxy-ethylene-dodecyl-ether (C12E8) represents the non-ionic surfactant and dodec-1-ene (C12) the oil component in the mixture.

Unfortunately, the experimental data basis in the literature for the binary subsystem water + C12E8 [3,4,5] is very limited, moreover they are not always consistent. In this contribution we present new experimental data related to miscibility gap showing a LCST-behavior of the aqueous surfactant solution. Additionally, the cloud point curve could be modeled using a detailed micellar formation model developed by Nagarajan and Ruckenstein [6]. This model allows the calculation of the aggregation behavior (i.e. critical micelle concentration, geometrical properties of the formed aggregates) and in combination with an expression for the excess Gibbs energy of mixing the calculation of the demixing curve close to the experimental data [7].

The binary subsystem C12 + water exhibits a large demixing gap, which was estimated using Karl-Fischer titration in order to determine the water content in the oil-rich phase and applying HPLC in combination with gas stripping in order to detect the very small oil-concentration in the water–rich phase. The water solubility at room temperature is in the order of magnitude of 10-8 expressed in mole fraction and depends only slightly on


temperature. The binary subsystem C12 + C12E8 shows no miscibility gap above the melting point of surfactant.

Figure 1. Schematic phase diagram of the ternary system.

The “Kahlweit fish” could be found for an oil-water ratio of 1:1. We present to the first time experimental data related to the ternary phase diagram of this system, where the experimental data include the “Kahlweit fish”, cloud point curves at different temperatures as well as tie lines at different temperatures. In order to measure the tie lines HPLC was applied for the determination of the concentration in the coexisting phases.

References [1] D. Evans, J.A. Osborn, G. Wilkinson, J. Chem. Soc. 33 (1968): 3133–3142. [2] M. Haumann, H. Koch, P. Hugo, R. Schomäker, Applied Catalysis A: General, 225 (2002) 239. [3] H. Fujimatsu, S. Ogasawara, S. Kuroiwa, Colloid Polym. Sci. 266 (1988) 594. [4] L.Q. Zheng, M. Suzuki, T. Inoue, N. Lindman, Langmuir 18 (2002) 9204. [5] M. Corti, C. Minero, V. Degiorgio, J. Phys. Chem. 88 (1984) 309. [6] R. Nagarajan, E. Ruckenstein, Langmuir 7 (1991) 2934. [7] S. Enders, D. Häntzschel, Fluid Phase Equilibria 153 (1998) 1. Acknowledgements The authors thank the German Science Foundation DFG for financial support related to the Collaborative Research Centre “Integrated Chemical Processes in Liquid Multiphase Systems” (SFB/TR 63/TPA5).


Modeling of Phase Equilibria in Microemulsion Systems Based on Partition Coefficients

Wille S., Sponsel E., Mokrushina L., Arlt W.

Friedrich-Alexander-University Erlangen-Nuremberg, Chair of Separation Science and Technology, Egerlandstr.3, 91058 Erlangen, Germany

[email protected]

Microemulsions have been successfully applied in the fields of surfactant-enhanced oil recovery, cosmetics, and pharmaceuticals, as reaction media (e.g., hydrogenation reaction) and for separation of reaction products in reaction engineering.

Microemulsions are mixtures of oil, water, and surfactant. They exist in a certain range of temperatures and compositions and are thermodynamically stable (one-phase) [1]. On the one hand, oil-water-surfactant systems enable the mixing of poor water soluble organic compounds and water by adding non-ionic surfactants. On the other hand, such systems offer the advantage to build one, two, or three phase systems changing only the temperature or the amount of surfactant which can be used for effective separation processes.

The temperatures Tu, Tl, T and the parameters 0γ and γ characterize the phase limits in the microemulsion system in the fish-like diagrams. Three-phase region (a microemulsion middle phase with excess phases of water and octane, fish body) occurs in the temperature range between Tu and Tl with the middle temperature T and in the fraction range of surfactant in the ternary system between 0γ and γ at fixed ratio of water and oil.

This paper focuses on thermodynamic modeling of the characteristic temperatures and compositions in the microemulsion systems based on partitioning. Two predictive thermodynamic based models are used here to calculate activity and thus partition coefficients: the group-contribution method UNIFAC and the a priori Conductor-like Screening Model for Real Solvents (COSMO-RS) based on quantum mechanics. Both models have been successfully used to model partitioning of solutes in micellar systems [2]. The main goal of the present study is to show the applicability of these models to predict the phase boundaries in the oil-water-surfactant systems.

As model systems, mixtures of octane, water, and non-ionic surfactants (ethoxylated alcohols such as Tetra-/Penta-/Hexaethyleneglycolmonododecylether and Tetra-/Pentaethyleneglycolmonodecylether) are considered. For the prediction of the phase boundaries, partition coefficients of one of the three system components between the two coexisting phases built up from the two other components are calculated at thermodynamic equilibrium. The composition of the two coexisting phases is assumed to correspond to the binary miscibility gap. The phase boundaries are then obtained based on characteristic concentration and partition coefficient profiles. Using this


method, the temperatures and system compositions that define the limits of three-phase region are determined. As a result, the temperatures Tu, Tl, T and the parameters 0γ and γ are predicted and compared with experimental values found in literature.

Both the UNIFAC and COSMO-RS models have been shown to be able to predict the temperature dependence of the three-phase region characteristics as well as their dependence on the amount of surfactant in the ternary system.

References [1] K. Holmberg, B. Jönsson, B. Kronberg, B. Lindman; Surfactants and polymers in aqueous solution, 2nd edition, John Wiley & Sons Ltd., Chichester, 2003 [2] L. Mokrushina, M. Buggert, I. Smirnova, W. Arlt, R. Schomäcker, Ind. Eng. Chem. Res. 2007, 46 (20), 6501


Applications of H-D Exchange Measurements for Protein Structure, Equilibria, and Kinetics

O'Connell J.P., Fernandez E.J.

University of Virginia, USA

[email protected]

When protein amide groups contact deuterated water, their hydrogen atoms can exchange with solvent deuterium atoms. This increases the protein’s mass, which can be detected by mass spectrometry. Careful protocols, including post-exchange protein digestion, can reveal exposed/protected residue locations and rates of protein conformational fluctuations.

The technique can be used to observe the effects on exposure/protection of many different variables as a function of time and at equilibrium. These include solvent conditions such as pH, added salt, and temperature; protein and additive concentrations; protein polypeptide sequence, and the chemistry of surfaces involved in protein adsorption. In particular, protein-protein and protein-additive interactions, as in association and solvation, and protein-surface interactions, as in chromatography, can be studied. In conjunction with other experiments, such as circular dichroism, calorimetry, and spectroscopy, behaviors of proteins can be found for use in biochemical studies, drug design, and biotechnology process development.

The presentation will briefly describe the HD exchange method and its application. Examples from the authors’ recent and forthcoming research studies will be shown for model and commercial proteins, including antibodies, with a focus on hydrophobic chromatography for separations, oligomerization of pharmaceutical products, and fibril formation [1–3].

References [1] R.W. Deitcher, J.P. O'Connell, E.J. Fernandez, J Chrom A, (2010), 1217, 5571-5583. [2] A.M. Gospodarek, M.E. Smatlak, J.P. O'Connell, E.J. Fernandez, Langmuir, (2011), 27, 286-295. [3] A. Zhang, J.L. Jordan, M.I. Ivanova, W.F. Weiss, C.J. Roberts, E.J. Fernandez, Biochemistry, (2010), 49, 10553-10564.


Solubility of Drug-Like Molecules in Pure, Mixed and Supercritical Solvent Systems with the CPA EoS

Mota F.L.1, Queimada A.J.1, Pinho S.P.2, Macedo E.A.1

1 - Laboratory of Separation and Reaction Engineering (LSRE), Departamento de Engenharia Quimica, Faculdade de Engenharia, Universidade do Porto, Rua do Dr. Roberto Frias, 4200-465

Porto, Portugal 2 - Laboratory of Separation and Reaction Engineering (LSRE), Departamento de Tecnologia Química e Biológica, Instituto Politécnico de Bragança, Campus de Santa Apolónia, Apartado

1134, 530-857 Bragança, Portugal

[email protected]

Most of the active pharmaceutical ingredients (API) are purified by crystallization being solubility a key property, and it also affects their efficacy, release, transport and absorption in the organism [1]. Although of extreme importance, data involving drug-like molecules are still scarce.

In recent years, efforts have been made towards the development of predictive tools to calculate phase behaviour of the API’s. Thermodynamic models are important tools, and namely activity coefficient based models have been applied for that purpose. Still, these frequently cannot describe with the desired accuracy broad temperature and pressure ranges, various solvent compositions or multifunctional molecules. Despite the success of the cubic-plus-association (CPA) equation of state (EoS), only very recently it was applied to model the phase equilibria of drug-like molecules, explicitly accounting for the number and nature of associating sites [2-3].

In this work, the quality of the solubility estimates provided by the CPA EoS for a set of drug-like molecules in aqueous, pure and mixed organic solvents, and supercritical fluids will be presented, being the experimental data obtained from literature. Molecules containing different and/or multiple associating groups such as acetylsalicylic, adipic, ascorbic and stearic acids, acetamide, hydroquinone, ibuprofen and paracetamol were studied both in aqueous and organic systems in a wide temperature range [2-3]. In water, the solubility of acetanilide, bisphenol A, camphor, dibenzofuran, hexachlorobenzene, nicotinic and terephthalic acids, piperazine, sorbitol and vanillin were additionally predicted [2]. Mixed solvent systems of ascorbic, nicotinic, stearic and terephthalic acids, acetanilide, hexachlorobenzene, ibuprofen, paracetamol, sorbitol and vanillin in a wide range of compositions were also studied.

Generally, modelling results are within the experimental uncertainties using a single temperature independent binary interaction parameter. The good results found for some of the compounds in water are presented in Fig. 1(a), and for paracetamol in organic solvents in Fig. 1(b).

Besides the importance of the studies at ambient pressure conditions, in the pharmaceutical industry some operations are performed in supercritical conditions,


being the equations of state particularly useful for these studies. Therefore, the solubility of drug-like molecules in supercritical solvents using CPA EoS was estimated, namely for acetylsalicylic, adipic, ascorbic, nicotinic and stearic acids, acetamide, camphor, dibenzofuran, hexachlorobenzene, hydroquinone, ibuprofen showing again that this EoS is particularly useful for that kind of systems.

T (K)280 300 320 340 360

x

10-11

10-10

10-9

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

xexperimental

0.00 0.02 0.04 0.06 0.08 0.10 0.12

x calc

ulat

ed

0.00

0.02

0.04

0.06

0.08

0.10

0.12

(a) (b) Figure 1. (a) Aqueous solubilities (, acetylsalicylic; ♦, nicotinic; , terephthalic acids; •, acetamide; ◊, bisphenol A; +, camphor; ×, dibenzofuran; , hydroquinone; , hexachlorobenzene) and CPA results. (b) Summarized results for paracetamol in: , ethanol; o, methanol; ♦, 2-propanol; ◊, acetone; , acetonitrile; , ethyl acetate; ∆, propylene glycol; , 1-propanol; ×, 1-butanol.

References [1] P. Kolář, J. W. Shen, A. Tsuboi, T. Ishikawa, Fluid Phase Equilib. 194 (2002) 771-782. [2] F. L. Mota, A. J. Queimada, S. P. Pinho, E. A. Macedo, Fluid Phase Equilib. 298 (2010) 75-82. [3] F. L. Mota, A. J. Queimada, S. P. Pinho, E. A. Macedo, Fluid Phase Equilib. (2011) accepted.


Activity Coefficients and Structure of Water in Amino-Acid Solutions

Hempel S., Sadowski G.

Laboratory of Thermodynamics, Department of Biochemical and Chemical Engineering, Technische Universität Dortmund, Germany

[email protected]

The knowledge of interactions between amino acids and water as well as the influence of the former on the water structure is crucial to understand the solution behavior of these systems as well as of peptides or even proteins. In this work we apply MD simulations to study these systems.

To obtain appropriate force fields for amino acids, quantum-chemical calculations were performed to receive the charge distribution. Its knowledge is crucial for a successful molecular-dynamics simulation. We optimized an approach developed by Vrabec et. al [1] who suggest MP2//6-311G(d,p) calculations using the Merz-Kollmann-Singh-scheme (MKS). In case of amino acids it is well known that the structure changes from the neutral form in the gas phase to a zwitterionic form in solution. Therefore, we performed the quantum-chemical calculations in a polarized continuum which accounts for the influence of water on the amino-acid structure in solution. Combined with parameters from the OPLS force field [2], a full set of parameters for the MD simulations was obtained. We applied this method to a series of aliphatic amino-acids such as e.g. glycine, alanine, α-aminobutyric acid, α-aminovalerianic acid, and valine.

Using the so-modified force fields we are able to simulate aqueous amino-acid solutions at various concentrations. The concentration of amino acids was altered over the whole region of solubility. To prove the quality of simulations we calculated water activity coefficients which are known to be a very sensible indicator of the system. Results from MD simulations have been found to be within ±3% of the experimental data and represent the correct order of water activity coefficients for different amino acids.

Considering the water-water radial distribution functions in these amino-acid solutions, trends in the first and second hydrogen layer attached to the solved amino acid can be observed. These trends can be associated to the change in activity coefficients which allows a direct conclusion to the kind of dominant interactions in the solution. We observe water-structure breaking tendencies for small amino acids like glycine and water-structure making effects for larger amino acids like α-aminovalerianic acid.


Figure 1. Water activity coefficients for a series of aliphatic amino-acids solutions as received

from molecular dynamics simulations.

References [1] B. Eckl, J. Vrabec, and H. Hasse, JPC B, 2008, 112(40), 12710-12721 [2] W.L. Jorgensen, J.D. Madura, and C.J. Swenson, JACS, 1984, 106(22), 6638-6646


Thermodynamic modeling of cross-association systems with the soft-SAFT EoS

Llovell F.1,2, Vilaseca O.1,2, Valente E.2, Jung N.2, Vega L.F.1,2

1 - Institut de Ciència de Materials de Barcelona. ICMAB-CSIC. Campus de la UAB. 08193 Bellaterra, Barcelona. Spain

2 - MATGAS Research Center (Carburos Metálicos/Air Products Group, CSIC, UAB), Campus de la UAB, 08193 Bellaterra, Barcelona. Spain

[email protected]

Historically, the thermodynamics of mixtures containing components with highly directional attractive molecular interactions has been a challenge, as classical equations of state did not explicitly consider those interactions in their models. In the case where more than one compound in the mixture was able to associate and form cross associates, the strong and directional nature of the association bonds had a big impact on their phase behavior, and their description with those models was generally poor, with high deviations from the experimental measurements. In this sense, the development of Wertheim’s theory of association [1-2] and, from it, the birth and expansion of the Statistical Associating Fluid Theory (SAFT) Equation of State (EoS) [3] was crucial for the improvement of the models to predict the thermodynamic behavior of those complex systems.

In this work, we aim to present a thermodynamic characterization of several systems that involve self and cross association by means of the soft-SAFT EoS [4], a variant of the original SAFT. In particular, we focus in two main families because of their industrial interest: the water + 1-alkanol systems and the ionic liquid mixtures.

From one side, the vapor-liquid and liquid-liquid equilibria of several mixtures of water + alkanol are described in good agreement with the experimental data. The calculation of the interfacial tension of these systems is also included. Additionally, we present a complete thermodynamic characterization of the three main families of current imidazolium ionic liquids, those with [BF4], [PF6] and [Tf2N] using a relatively simple model [5-6], where the cation and the anion are considered as a chain with several associating sites. Single phase and two-phase equilibrium, vapor pressure (if available), interfacial tension and derivative properties are provided in a wide range of temperatures and pressures in good agreement with experimental data. Then, the solubility of these families in aqueous mixtures with alcohols and water is predicted.

In all cases, an appropriate association model is proposed for each compound and a matrix considering cross-association is built when necessary, looking always for the main physical features of the system. In most of the cases, cross-association values are predicted from the Lorentz-Berthelot rules, and no experimental data of the mixture is needed to fit the parameters.


Figure 1. Solubility of water in [C2-mim][Tf2N] at 292.75K (squares), 303.20K (diamonds), 323.35K (circles) and 353.15K (triangles). This work was partially financed by the Spanish Government under projects CTQ2008-05370/PPQ and CENIT SOSTCO2 (CEN-2008-1027, Programa Ingenio 2010). Additional support from Carburos Metálicos, Air Products Group and the Catalan Government was also provided (2009SGR-666).

References

[1] M.S. Wertheim, J. Stat. Phys., (1984), 35, 19-34. [2] M.S. Wertheim, J. Stat. Phys., (1984), 35, 35-47. [3] W.G. Chapman, K.E. Gubbins, G. Jackson, M. Radosz, Ind. Eng. Chem. Res., (1990), 29, 1709-1721. [4] F.J. Blas, L.F. Vega, Molecular Physics, (1997), 92, 135-150. [5] J.S. Andreu, L. F. Vega, J. Phys. Chem. C, (2007), 111, 16028-16034. [6] F. Llovell, E. Valente, O. Vilaseca, L.F. Vega, (2010), submitted


Modeling of the dissociation conditions of salt hydrates and gas semiclathrate hydrates. Application to lithium bromide,

hydrogen iodide hydrates, and mixed hydrates of gas + Tetra-n-butylammonium bromide

Paricaud P., Bouchafaa W., Dalmazzone D.

Laboratoire de Chimie et Procédés, ENSTA ParisTech, 32 bd Victor, 75739 Paris cedex 15, France

[email protected]

Salt hydrates are solid compounds formed by the combination of the ions with a definite number of water molecules. Tetraalkylammonium halide semiclathrate hydrates have recently received much attention from both industrials and researchers, as they can be used as refrigerants, gas separation and gas storage materials. In presence of gas molecules, tetraalkylammonium halide + water systems can form gas semiclathrate hydrates at low pressures and near room temperature.

A new thermodynamic approach [1] is proposed to determine the dissociation conditions of salt hydrates and semiclathrate hydrates. The thermodynamic properties of the liquid phase are described with the SAFT-VRE equation of state [2], and the solid-liquid equilibria are solved by applying the Gibbs energy minimization criterion under stoichiometric constraints. The methodology is first applied to water + halide salt systems, and an excellent description of the solid-liquid coexistence curves is obtained. The approach is extended to the water + tetra-n-butylammonium bromide (TBAB) binary mixture, and an accurate representation of the solid-liquid coexistence curves and dissociation enthalpies is obtained.

The van der Waals-Platteeuw (vdW-P) theory combined with the new model for salt hydrates is used to determine the dissociation temperatures of semiclathrate hydrates of TBAB + CO2. A good description of the dissociation pressures of CO2 semiclathrate hydrates is obtained over wide temperature, pressure and TBAB composition ranges (AAD = 10.5%). For high TBAB weight fractions the new model predicts a change of hydrate structure from type A to type B, as the partial pressure of CO2 is increased. The model can also capture a change of behavior with respect to TBAB concentration, which has been observed experimentally: an increase of the TBAB weight fraction leads to a stabilization of the gas semiclathrate hydrate at low initial TBAB concentrations below the stoichiometric composition, but leads to a destabilization of the hydrate at TBAB concentrations above the stoichiometric composition. We also present modelling results vs. experimental measurements of H-L-V equilibrium data in the systems tetra-n-butylammonium bromide (TBAB) + (yCO2 + (1-y)N2) + H2O, where 0< y <1.


References [1] Paricaud P. , J. Phys. Chem. B, in press (2011). [2] Galindo, A.; Gil-Villegas, A.; Jackson, G.; Burgess, A. N. J. Phys. Chem. B 1999, 103, 10272-10281.


Molecular Simulation of Aqueous Electrolyte Solutions – New Force Fields for Monovalent Anions and Cations

Deublein S.1, Reiser S.1, Vrabec J.2, Hasse H.1

1 - University of Kaiserslautern - Laboratory of Engineering Thermodynamics, Germany 2 - University of Paderborn - Thermodynamics and Energy Technology, Germany

[email protected]

Aqueous electrolyte solutions play an important role in many industrial applications, especially in chemical and pharmaceutical industry. Electrolytes influence the thermodynamic properties of solvents dramatically, an effect that is taken advantage of in protein downstream processing. Understanding these solutions is of prime interest. Unfortunately, the distinct microscopic structure, which develops due to the strong long range interactions, and the thermodynamic properties are difficult to model. Established phenomenological models of electrolyte solutions offer a multitude of fitting parameters and are often only good for interpolations. In the present work, we try to overcome these drawbacks by consequently applying molecular modeling and simulation on the basis of classical force fields with explicit solvent and ion models to determine the thermodynamic properties of aqueous electrolyte solutions. The focus lies on monovalent alkali metal cations, and anions from the halogen group. Each ion is modeled as one Lennard-Jones (LJ) sphere with a single point elementary charge in its center of mass. Hence, each ion model has only two adjustable parameters, namely the LJ size and energy parameter. Water is modeled using force fields of the LJ + partial charge type from the literature, namely SPC/E and TIP4P.

A systematic study on force fields from literature revealed that they generally fail when applied for predictions of thermodynamic properties. This is illustrated on the basis of the reduced density, i.e. quotient of the density of the solution and that of pure water. Given the deficiencies of the ion models from the literature, new ion force fields were developed in the present study. The size parameter was adjusted to the reduced solvent density, whereas the energy parameter (which does not significantly influence the density) was fitted to activity data. The new models perform well over a wide range of ionic strengths and predict structural properties like radial distribution functions and hydration numbers well. They are also shown to be transferable, i.e. they hold for all salts, i.e. anion/cation combinations. The fitting procedure is non-trivial as only neutral solutions containing anions and cations can be studied. A global fitting approach was developed and successfully applied which will be explained in the presentation. Work on the prediction of the diffusion coefficients of the different species in the studied solutions is currently in progress, first results will be presented. The simulations described above were performed with the molecular simulation program ms2. The long range interactions of the charges were considered by Ewald summation.


Accounting for Non-classical Critical Scaling with DMD/TPT in the Long Chain Limit

Elliott J.R., Ghobadi A.F.

University of Akron, USA

[email protected]

DMD/TPT is based on Discontinuous Molecular Dynamics (DMD) and second order Thermodynamic Perturbation Theory (TPT). DMD simulation is applied to the repulsive part of the potential, complete with molecular details like interpenetration of the interaction sites, 110° bond angles, branching, and rings. The thermodynamic effects of disperse attractions and hydrogen bonding are treated by TPT. This approach accelerates the molecular simulations in general and the parameterization of the transferable potentials in particular. Transferable potentials have been developed and tested for over 500 components comprising 30 families.

The DMD/TPT formalism is especially amenable to engineering application of molecular simulations because it yields a complete equation of state as a result of characterizing the perturbation coefficients. One caveat of this approach, however, is the non-classical scaling in the critical region. Even molecular simulations of the full potential are limited by finite size effects when it comes to representing critical scaling.1,2 The DMD/TPT formalism is further constrained because the perturbation series is inherently an analytic equation of state. This indicates a need to incorporate corrections for non-classical scaling like those of White or those of Kiselev and coworkers.3-5

A byproduct of the DMD/TPT formalism is the ability to extrapolate the trends in the perturbation coefficients to the infinite chain limit.6 On the other hand, Lue et al. have articulated several concerns related to the virial coefficients and compressibility factor in the infinite chain limit.7 In the present work, we show how to combine the trends in perturbation coefficients with White's method to infer the trend in the critical compressibility factor in the infinite chain limit. The result is a universal equation of state that describes the critical compressibility factor for all chain lengths using a transferable intermolecular potential model.

References 1. Orkoulas, G.; Panagiotopoulos, A. Z., Phase behavior of the restricted primitive model and square-well fluids from Monte Carlo simulations in the grand canonical ensemble. J. Chem. Phys. 1999, 110, 1581-1590. 2. Kiselev, S. B.; Ely, J. F.; Elliott, J. R., Molecular dynamic simulations and global equation of state of square-well fluids with the well-widths from 1.1 to 2.1 diameters. Mol. Phys. 2006, 104, 2545-2559.


3. Lue, L.; Prausnitz, J. M., Renormalization-group corrections to an approximate free-energy model for simple fluids near to and far from the critical region. J. Chem. Phys 1998, 108, 5529. 4. LLovell, F.; Pamies, C. J.; Vega, F. L., Thermodynamic properties of Lennard-Jones chain molecules: renormalization-group corrections to a modified statistical associating fluid theory. J. Chem. Phys 2004, 121, 10715. 5. Kiselev, S. B.; Ely, J. F., Crossover SAFT Equation of State:application for Normal Alkanes. Ind. Eng. Chem. Res. 1999, 38, 4993. 6. Elliott, J. R.; Gray, N. H., Asymptotic Trends in Thermodynamic Perturbation Theory. J. Chem. Phys. 2005, 123, 184902. 7. Lue, L.; Friend, D. G.; Elliott, J. R., Critical Compressibility Factors for Chain Molecules. Mol. Phys. 2000, 98, 1473-1477.


A new concept for augmented van der Waals equations of state

Nezbeda I.1, Trokhymchuk A.2, Melnyk R.2

1 - Faculty of Science, J.E. Purkinje Univ., Usti n. L., Czech Republic 2 - Inst. Condensed Matter Phys., Ukraine Acad. Sci., Lviv, Ukraine

[email protected]

The commonly used augmented van der Waals (vdW) equations are based on the hard sphere(hard body) primary contribution to the properties of fluids and makes use of availability of a number of analytic results for their properties. Nonetheless, this choice suffers from two defects:

(i) inaccuracy when only one simple correction term is used, and (ii) limitation to ambient and not too much elevated temperature range only.

As an attempt to remove these drawbacks we have recently formulated an expansion (augmented vdW EOS) about a reference system with soft interactions which, within the spirit of a unified view of fluids, incorporates also the attractive interaction at short separations.

The proposed approach is based on a short range Yukawa reference and the knowledge of the Yukawa fluid properties and its flexibility. The methodology of the approach will be formulated and then its implementation for the three most important simple fluids, the Sutherland, Lennard-Jones, and EXP6 fluids, will be presented. Particularly, the application of the method to the EXP6 fluids extends the applicability of augmented vdW equations to the region of supercritical conditions and very high pressures, i.e. the region where a special theoretical treatment is required and the available results are either only in a numerical form or represent only empirical correlations.

The presented results clearly show that the suggested approach may provide a simple and yet quite accurate augmented vdW equation in an analytic form able to perform over a very large range of thermodynamic conditions.


Modelling of Complex Hydrocarbon Droplet Heating and Evaporation: Hydrodynamic, Kinetic and Molecular

Dynamics Approaches

Sazhin S.S.1, Elwardany A.1, Gusev I.G.1, Xie J.-F.1, Cao B.-Y.2, Shishkova I.N.3, Snegirev A.Yu.4, Heikal M.R.1

1 - Sir Harry Ricardo Laboratories, School of Computing, Engineering and Mathematics,University of Brighton, Brighton BN2 4GJ, U.K

2 - Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P. R. China 3 - Low Temperature Department, Moscow Power Engineering Institute, Moscow 111250,

Russia 4 - Saint-Petersburg State Polytechnic University, Polytechnicheskaya, 29, Saint-Petersburg

195251, Russia

[email protected]

Some recent results referring to hydrodynamic, kinetic and molecular dynamics (MD) modelling of complex hydrocarbon droplet heating and evaporation in Diesel engine-like conditions are critically reviewed. These results include the hydrodynamic modelling, taking into account the effects of moving boundary during the evaporation process [1,2] and the effects of multiple components in the liquid phase [3], kinetic modelling, taking into account both heat and mass transfer in the Knudsen layer [4,5] and molecular dynamics (MD) modelling, taking into account the complex nature of the molecules [6].

Two new solutions to the heat conduction equation, describing transient heating of an evaporating droplet, are suggested [1]. The first solution is the explicit analytical solution to this equation, while the second one reduces the solution of the differential transient heat conduction equation to the solution of the Volterra integral equation of the second kind. Both solutions take into account the effect of the reduction of the droplet radius due to evaporation, assuming that this radius is a linear function of time. This approach can be considered as the generalisation of the approach currently used in all research and commercial CFD codes known to us, in which it is assumed that droplet radius is constant during the time step. The new analytical solution has been incorporated into a zero dimensional CFD code and applied to the analysis of Diesel fuel droplet heating and evaporation in typical engine conditions. It has been pointed out that the new approach predicts lower droplet surface temperatures and slower evaporation rates compared with the traditional approach. New solutions to the heat conduction equation, describing transient heating of an evaporating droplet, are suggested, assuming that the time evolution of droplet radius Rd(t) is known [2]. The initial droplet temperature is assumed to be constant or allowed to change with the distance from the droplet centre. Since Rd(t) depends on the time evolution of the droplet temperature, an iterative process is required. The results of these calculations are compared with the results obtained using the previously suggested approach when the droplet radius was assumed to be a linear


function of time during individual time steps for typical Diesel engine-like conditions. For sufficiently small time steps the time evolutions of droplet temperatures and radii predicted by both approaches coincided.

A simplified model for bi-component droplet heating and evaporation is developed and applied for the analysis of the observed average droplet temperatures in a monodisperse acetone/ethanol spray [3]. The model takes into account all key processes, which take place during this heating and evaporation, including the distribution of temperature and diffusion of liquid species inside the droplet and the effects of the non-unity activity coefficient. The previously obtained analytical solution to the transient heat conduction equation inside droplets is incorporated in the numerical code alongside the original analytical solution to the species diffusion equation inside droplets. The non-zero gradient of the mass fraction of species shows the limitations of widely used simplified models based on the assumptions of zero or infinitely large species diffusivities.

Simple approximate formulae, describing temporal evolution of Diesel fuel droplet radii and temperatures predicted by the kinetic model, are suggested. These formulae are valid in the range of gas temperatures and fixed values of initial droplet radii, or in the range of initial droplet radii and fixed values of gas temperature. The new approximations are shown to be reasonably accurate for predicting the temporal evolution of droplet radii and droplet evaporation times.

Preliminary molecular dynamics (MD) simulations are performed to study the evaporation and condensation of n-dodecane (C12H26) at temperatures in the range 400-600 K [6]. A modified OPLS (Optimized Potential for Liquid Simulation) model is applied to take into account the Lennard-Jones, bond bending and torsion potentials with the bond length constrained. A number of new processes, including reflection condensation and trapping-desorption evaporation/condensation, have been observed at the n-dodecane liquid-vapour interface, but not at the interfaces of substances with simple molecules. The reflection and trapping-desorption evaporation/condensation processes are shown to be dominant in the overall evaporation/condensation process.

References [1] S.S. Sazhin, P.A. Krutitskii, I.G. Gusev, M. Heikal, International J of Heat and Mass Transfer (2010) 53 (13-14), 2826-2836. [2] S.S. Sazhin, P.A. Krutitskii, I.G. Gusev, M. Heikal, International J of Heat and Mass Transfer (2011) 54 (5-6), 1278-1288. [3] S.S. Sazhin, A. Elwardany, P.A. Krutitskii, G. Castanet, F. Lemoine, E.M. Sazhina, M. Heikal, International J of Heat and Mass Transfer (2010) 53 (21-22), 4495-4505. [4] S.S. Sazhin and I.N. Shishkova, Atomization and Sprays (2009) 19 (5), 473-489. [5] S.S. Sazhin, I.N. Shishkova, and M. Heikal, International J of Engineering Systems Modelling and Simulation (2010) 2 (3), 169-176. [6] B.-Y. Cao, J.-F. Xie and S.S. Sazhin, J Chemical Physics (2011) (submitted).



SESSION 6: Interfacial Phenomena


Grand Potential for Solids and Solid-Fluid Interfaces

Tatyanenko D.V., Rusanov A.I., Shchekin A.K.

St. Petersburg State University

[email protected]

The tensor nature of chemical potential of immobile component of solid, its principal nonuniformity (due to impossibility of diffusion) makes thermodynamics of bulk solid and its surface different from more simple thermodynamics of fluids [1,2]. For a fluid system, the grand thermodynamic potential is defined as i i

iF NµΩ = −∑ , (1)

where F is the free energy of the system and µi and Ni are the chemical potential and the number of molecules of the ith species, respectively. The thermodynamic surface tension σ introduced by Gibbs can be determined as / Aσ = Ω , (2) where the bar denotes a surface excess value and A is the dividing surface area. For a planar interface, the position of the dividing surface can be chosen arbitrarily and the surface tension (2) does not depend on it. For a solid-fluid interface, the natural choice of the dividing surface is the boundary surface of solid. It becomes the equimolecular one with respect to the component of solid for the case of a single-component solid. However, sometimes it is more convenient to choose another solid-fluid dividing surface. E.g., for sessile droplets, it is natural to shift the dividing surface by the thickness of wetting film formed on the solid substrate. Upon the arbitrary choice of dividing surface, an additional term with adsorption(s) appears in relations for excess quantities. To treat an arbitrary shift of a planar solid-fluid dividing surface, we have introduced the grand potential of the solid-fluid system as [3] i i j j

iF N Nβµ µΩ = − −∑ . (3)

Here i denotes the mobile components present in both fluid and solid phases, and j denotes the immobile component of the solid phase (suggested to be the only immobile component). Component j is supposed to be mobile (e.g., dissolved) at the chemical potential j

βµ in the adjacent fluid phase β. Phase equilibrium assumes ( )j z jα βµ µ= and

zE pα β= − where the superscript α marks the solid phase, ( )j zαµ is the principal value of

the chemical potential tensor ˆ jαµ [1], zEα is the principal value of the stress tensor Eα ,

both corresponding to the direction z normal to the solid surface; pβ is the pressure in the fluid phase β. The definition (3), being applied to the homogeneous bulk phases, gives ( )( ) , , , ,k j k j jE V N k x y z p Vα α α α β α β β βµ µΩ = + − = Ω = − , (4)


or, passing to the density of grand thermodynamic potential /Vω ≡ Ω , ( )( ) , , , ,k j k j jE c k x y z pα α α β α β βµ µ ωΩ = + − = = − , (5)

where c stands for the concentration (the number density). Since ωα cannot depend on direction, Eq. (5) implies the equalities ( ) ( ) ( )x j x j y j y j x j z jE c E c E cα α α α α α α α αµ µ µ+ = + = + . (6) Passing to the interface and introducing the local concentration cj(z), the interfacial local density of grand thermodynamic potential can be written as ( )( ) ( ) ( ) ( ), , ,k j k j jz E z z c z k x y zβω µ µ = + − = . (7)

To calculate the surface excess quantity / Aω = Ω , we introduce the dividing surface at

0z z= , thus yielding the expression 0

0

[ ( ) ] [ ( ) ]z

zz dz z dzα βω ω ω ω ω

∞

−∞= − + −∫ ∫ .

Substituting expressions (5)–(7), we obtain ( )( ) ( ) , ,k j k j k j jg k x yα β αω γ µ µ= + + − Γ = (8)

with the mechanical surface tension tensor defined as

0

0

[ ( ) ] [ ( ) ] , ,z

k k k kz

E z E dz E z p dz k x yα βγ∞

−∞

≡ − + + =∫ ∫ , (9)

the adsorption at the side α defined as 0 [ ( ) ]z

j jc z c dzα α−∞

Γ ≡ −∫ , and the tensorial quantity

g characterizing interfacial non-uniformity of the chemical potential ˆ jµ defined as

0

0

( ) ( ) ( ) ( )( ) ( ) ( ) ( ) , ,z

j k j k j k j j k j jz

g z c z dz z c z dz k x yα βµ µ µ µ∞

−∞

≡ − + − = ∫ ∫ . (10)

Using Eqs. (5)–(6), it can be derived that, similarly to a fluid-fluid interface, 0/ 0d dzω = , i.e. ω does not depend on the position of the dividing surface. Finally,

employing a thought construction with cutting up the solid body (Ref. [1], p. 192), one can show that σ ω= for an arbitrary position of the dividing surface provided the definition of σ as the work of formation of a unit new surface is employed. The latter two conclusions make it possible to re-define σ using formula (2) now applicable to surfaces of both fluids and solids at an arbitrary choice of the (planar) dividing surface, provided the introduced potential (3) is used. In the absence of equilibrium with a real fluid with the dissolved component j, one can use another definition of the grand potential substituting ( )j z

αµ for jβµ as if the condition

of the chemical equilibrium is fulfilled: ( )i i j z j

iF N Nαµ µΩ = − −∑ . (11)

References [1] A.I. Rusanov, Surf. Sci. Rep. (1996), 23, 173–247. [2] A.I. Rusanov, Surf. Sci. Rep. (2005), 58, 111–239. [3] A.I. Rusanov, A.K. Shchekin, D.V. Tatyanenko, J. Chem. Phys. (2009), 131, 161104.


Fundamental issues of metal/ceramic interfacial reactions: thermodynamics and kinetics

Hodaj F.

Grenoble Institute of Technology, France

[email protected]

Interfacial reactions between liquid metals and ceramics are of technological importance in many fields of materials engineering such as joining of ceramics by brazing alloys, manufacturing of metal/ceramic composites, casting of metals, etc.

In non-reactive metal-ceramic systems non-wetting is usually observed. In these systems, wetting can be significantly improved by certain alloying elements which form continuous layers of compounds at the interface, by reaction with the ceramic substrate.

Such reactions are used in practice to promote wetting, especially for joining of ceramics by brazing alloys. As this reactivity can affect the physical properties of the interface and especially the mechanical behaviour of the system, it is important to control the nature, morphology and microstructure of the reaction product.

The purpose of this presentation is to focus on the fundamental issues of metal/ceramic interfacial reactions and to analyse the main thermodynamic and kinetic factors governing these reactions. In particular, some physicochemical aspects which can affect, or even control, the morphological evolution of the interfacial region will be discussed by using and analysing different examples of interactions between oxide or non-oxide ceramics and reactive liquid alloys.


Phase transitions of water in mica and graphite pores

Srivastava R.1, Docherty H.2, Singh J.K.1, Cummings P.T.2

1 - Indian Institute of Technology Kanpur, Department of Chemical Engineering, Kanpur, India 2 - Department of Chemical Engineering, Vanderbilt University, Nashville, TN, USA

[email protected]

Vapor-liquid phase transition of water is examined in hydrophilic and hydrophobic pores. We perform all-atom molecular dynamics simulations of water confined in graphite and mica slit pores of variable size ranging from 10 – 60 Å. For each pore size, we present in detail the phase diagrams and associated critical properties (critical temperature cT and density cρ ) of the first and second layers adjacent to the pore surface (denoted I and II) and the layer at the center of the pores. In general, for both hydrophobic and hydrophilic pores, we observe the critical temperature of the central layer to be higher than that of the first layer. On the other hand, the critical density of the central layer is found to be lower than that of the first layer. In the case of water in graphite pores, we found specifically that , , ,c I c II c centerT T T< < and , , ,c I c center c IIρ ρ ρ< < . In addition, we note that the coexisting phase near the surface behaves more like a 2D fluid while the fluid in the center of pore is 3D bulk-like with this difference being more pronounced in hydrophilic pores. Finally, we also report the molecular ordering and hydrogen bonding of confined water in graphite and mica pores.


Surface tension of atmospheric solutions. Modeling aqueous organic-inorganic mixtures

Dalirian M., Dehghani M.R.

Iran University of Science and Technology

[email protected]

Nowadays, measurement and modeling of surface tension for multi-component mixture containing ambient aerosol including Carboxylic acids, Alcanoic acids and other carbonaceous species is very interesting because of their role on supersaturating of cloud droplets in the atmosphere. It is known that a large fraction of aerosol particles is inorganic salts (Dusek et al., 2006; McFiggans et al., 2005). Owing to their hygroscopicity, salt particles act as efficient cloud condensation nuclei (CCN). Measurements of chemical composition of aerosol particles have shown also that, in addition of inorganic salts, an extensive number of both water-soluble and water-insoluble organic acids are present in the aerosol phase (Legrand et al., 2007). They are formed for example via gas to particle conversion that results from the oxidation of volatile organic compounds (Kroll and Seinfeld, 2008) [4]. Surface tension (σ) is an important parameter in the Köhler theory (Köhler, 1936), which describes the activation of an aerosol particle into a cloud drop. Köhler theory predicts the supersaturating (S) of water vapor over a solution droplet of a given radius (r):

(1)

Where p is the water vapor pressure over the droplet solution, p0 is the water vapor pressure over a flat water surface, aw is the water activity in the droplet solution, σ is the surface tension of the droplet solution, Mw is the molecular weight of water, ρ is the density of water, R is the universal gas constant and T is the temperature. The vapor pressure is decreased by the dissolved matter (the Raoult effect, represented by Raoult’s law) while the curvature of the droplet exerts an opposite effect (the Kelvin effect, accounted for by the exponential term which is dependent on the surface tension of the solution [6]). Therefore, based on the Köhler theory, water activity and surface tension of aqueous solution containing organic and inorganic species are the main parameters in cloud critical super saturation. A reduction in surface tension, relative to that of pure water, can lower the magnitude of critical supersaturating; thereby increasing the number density of activated droplets (Twomey, 1974) [2]. The complex behavior of multi-component aerosol particles in the moist atmosphere requires predictive frameworks which attempt to capture the complexity of the organic composition and its combination with inorganic compounds [3].

In this study, a predictive model has been introduced to estimate the surface tensions of aqueous organic-inorganic mixtures. This model is a coupled model, which is a


combination of Hänel equation for inorganic species which is assumed a linear behavior of surface tension with concentration variations and Szyszkowski equation for organic materials. The results of modeling can be useful for extrapolation of experimental data outside of solubility limits of species which can be found in super saturation conditions in atmospheric droplets.

In this study, experimental data for surface tension of binary aqueous solutions of organic and inorganic materials have been used to fit parameters of Hänel and Szyszkowski equations[1], [2], [5]. After that, these fitted parameters have been used to predict the surface tension of ternary aqueous organic-inorganic mixtures.

The results have been presented in Table 1. It is shown that the proposed model could correlate the results with acceptable accuracy.

Table 1: Studied mixtures and absolute average deviation of surface tension prediction for these

systems

Aqueous mixture Np Ref. AAD%

(NH4)2SO4-Pinonic acid 6 [3] 3.22 (NH4)2SO4-Succinic acid 5 [3] 1.98 NH4NO3-Succinic acid 31 * 0.30 NH4NO3-Adipic acid 31 * 0.88 NaCl-Succinic acid 64 [4] 1.64 NaCl-Pinonic acid 41 [5] 2.59 NaCl-Oxalic acid 4 [3] 1.04 Na2SO4-Pinonic acid 12 [5] 2.37 NH4Cl-Pinonic acid 17 [5] 2.04 Overall AAD% 1.79

* Data measured by authors References [1] B. Svenningsson, J. Rissler, E. Swietlicki, M. Mircea, M. Bilde, M.C. Facchini, S.

Decesari, S. Fuzzi, J. Zhou, J. Mønster and T. Rosenørn, Atmos. Chem. Phys., (2006), 6, 1937–1952.

[2] E. Aumann, L.M. Hildemann and A. Tabazadeh, Atmospheric Environment, (2010), 44, 329-337.

[3] D.O. Topping, G.B. McFiggans, G. Kiss, Z. Varga, M.C. Facchini, S. Decesari and M. Mircea, Atmos. Chem. Phys.,(2007), 7, 2371–2398.

[4] J. Vanhanen, A.P. Hyvärinen, T. Anttila, T. Raatikainen, Y. Viisanen, and H. Lihavainen, Atmos. Chem. Phys., (2008), 8, 4595–4604.

[5] R. Tuckermann, Atmospheric Environment, (2007), 41, 6265–6275. [6] Z. Varga, G. Kiss, and H.C. Hansson, Atmos. Chem. Phys., (2007), 7, 4601–4611.


A new route to evaluate the curvature dependence of the surface tension of vapour-liquid interfaces by molecular

simulation

Horsch M.1,2, Miroshnichenko S.2, Vrabec J.2, Shchekin A.K.3, Müller E.1, Jackson G.1

1 - Imperial College London, Department of Chemical Engineering, London SW7 2AZ, England

2 - University of Paderborn, Department of Mechanical Engineering, Thermodynamics and Energy Technology Laboratory, Warburger Str. 100, 33098 Paderborn, Germany

3 - St. Petersburg State University, Theoretical Physics Department, Fock Research Institute of Physics, ul. Ul'yanovskaya 1, Petrodvorets, St. Petersburg, 198504 Russia

[email protected]

The Tolman equation [1]

20 1 ( ),p O pγ δγ γ

= + ∆ + ∆ (1)

expresses the surface tension γ of a nanodroplet in terms of the surface tension of the planar interface γ0, the pressure difference between the coexisting fluid phases ∆p and the Tolman length δ, defined as the deviation between two characteristic radii

e2 ,R

pγδ = −

∆ (2)

the equimolar radius Re and the Laplace radius 2γ / ∆p. At present, however, a striking disagreement prevails regarding the magnitude of the Tolman length and even its sign. In case of droplets, Tolman expected δ to be positive [1]. Nonetheless, more recent studies found δ to be negative [2] or equal to zero [3], while others claim that its sign is curvature dependent itself [4]. Thereby, only the mutual inconsistency of the employed assumptions and methods has been proven, while nothing quantitative is truly known about δ and the dependence of γ on the droplet radius. In the present work, the curvature dependence of the surface tension is related to the excess equimolar radius η, defined by

0e

2 ,Rp

γη = −∆

(3)

i.e. by the deviation between the equimolar radius Re of a droplet and its Laplace radius according to the capillarity approximation (γ = γ0). In line with an interpretation of the Tolman approach in the planar limit, i.e. ∆p → 0, recently proposed by van Giessen and Blokhuis [2], Eqs. (1) to (3) imply that the Tolman length and the excess equimolar radius converge to values of equal magnitude and opposite sign

e e

lim lim ,R R

η δ→∞ →∞

= − (4)


as the radius increases. The surface tension of nanodroplets can thus be discussed by following a new route that relies exclusively on calculations, e.g. by molecular simulation, of the density profile (yielding Re) and the chemical potential (yielding ∆p). This avoids the intricacies of computing γ by means of a pressure tensor or effective variations of the surface area, as required by other molecular simulation methods. Here, droplets of the truncated-shifted Lennard-Jones (TSLJ) fluid are considered using molecular dynamics (MD) simulation in the canonical ensemble, with equimolar radii ranging between 6 and 16 times the size parameter σ. From an analysis of these simulations, the deviation of the equimolar radius from capillarity (and, by consequence, the magnitude of the Tolman length) is found to be smaller than 0.5 σ, cf. Fig. 1, which is consistent with data from previous work [5]. Other methodical approaches, which have led to contradicting claims in the past, are critically discussed.

Figure 1. Parity plot of the equimolar radius Re with respect to the radius expected from the capillarity approximation, from the present canonical MD simulations of the TSLJ fluid at the temperatures T = 0.75 () and 0.85 ε / kB (), where ε is the energy parameter of the pair potential, in comparison with results of Vrabec et al. [5] at T = 0.75 (∆) and 0.85 ε / kB (). Deviations from the diagonal (– –) correspond to η which in the planar limit evaluates to −δ. References [1] R. C. Tolman, J. Chem. Phys. (1949), 17, 333. [2] A. E. van Giessen, E. M. Blokhuis, J. Chem. Phys. (2009), 131, 16705. [3] Y. A. Lei, T. Bykov, S. Yoo, X. C. Zeng, J. Am. Chem. Soc. (2005), 127, 15346. [4] J. Julin, I. Napari, J. Merikanto, H. Vehkamäki, J. Chem. Phys. (2010), 133, 044704. [5] J. Vrabec, G. K. Kedia, G. Fuchs, H. Hasse, Mol. Phys. (2006), 104, 1509.


New approach to the surface charging of metal oxides in nonaqueous solvents

Kosmulski M.1, Próchniak P.1, Mączka E.1, Rosenholm J.B.2

1 - Lublin University of Technology, Lublin, Poland 2 - Abo Akademi, Department of Physical Chemistry, Abo, Finland

[email protected]

The surface charging of metal oxides in aqueous solutions is due to preferential adsorption of ions, but such an approach is not applicable for low-dielectric-constant media. Namely, the dissociation constants of electrolytes in nonaqueous solvents are low, and the number of pre-existing ions is not sufficient to produce a high surface charge density. The surface-induced electrolytic dissociation was proposed as a model explaining the existence of surface charges in low-dielectric-constant media. Molecular solutes interact with solid particles and produce adsorbed ions and solvated ions in solution. Thus the surface is charged in spite of a very low concentration of pre-existing ions in solution. Large sizes of the products of reaction prevent their association. An experimental evidence for surface-induced electrolytic dissociation in semi-polar solvents is presented.


Sunday, 26.06.2011

PLENARY SESSION


Materials for carbon capture and utilization in the context of sustainable energy development

Vega L.F.1,2,3, Builes S.3,2, López-Aranguren P.3,2, Pacciani R.3,1, Ramirez R.3, Domingo C.2

1 - Carburos Metálicos, Air Products Group. C/ Aragón 300. 08009 Barcelona. Spain 2 - Institut de Ciencia de Materials de Barcelona. Consejo Superior de Investigaciones

Cientificas. ICMAB-CSIC. Campus UAB. 08193 Bellaterra, Barcelona. Spain 3 - MATGAS Research Center (Carburos Metálicos/Air Products, CSIC, UAB). Campus UAB.

08193 Bellaterra, Barcelona. Spain

[email protected]

As defined by the Brundtland Commission, sustainable development is the development that “meets the needs of the present without compromising the ability of future generations to meet their own needs”. Sustainable development is of special relevance in the present situation, in which an explosive growth in energy consumption as a consequence of the great inventions and developments related transportation, computers and technology is observed, along with a rapid increase in population worldwide. Most of the great technologies mentioned are related to an increased amount of green house gases emitted to the atmosphere. In this context, sustainable development would suggest searching for ways to mitigate these emissions, including carbon capture and storage (or utilization), energy efficiency, alternative sources of energy and energy saving, as already suggested by the Kyoto's protocol and the IPCC reports. Much effort is devoted to capture and storage of CO2 from concentrated sources of emission such of power plants and others. Traditionally industrial separation of CO2 is performed using aqueous amines. One of the main challenges of this process is that it consumes a large amount of energy for the regeneration of the amine [1]. This occurs primarily due to the high heat capacity of water. Therefore in order to avoid the energetic penalty of heating water, a suitable alternative to this process is to use the solid analogue of the amine solution. In this presentation we will first provide an overview of the present situation in the context of CO2 capture and utilization, briefly mentioning available technologies for CO2 capture and their limitations [2]. The second part of the presentation deals with specific studies we are carrying on related to materials to improve the CO2 capacity for reversible absorption (including organic-inorganic functionalized materials and zeolite template carbons) or permanent sequestration (refined calcium carbonate and related materials). We will present very recent results concerning the use of functionalized mesoporous silica adsorbents. These materials are one of the most promising mid-term alternatives to achieve a viable alternative for CO2 separation and capture [3]. The effective design of these materials requires a method that can relate the structure of the adsorbent to its performance in the application of interest. An understanding of the physics behind them can be achieved by using molecular simulations, as they relate the microscopic behavior of the molecules during the adsorption process to the macroscopic


behavior of the system, allowing one to search for the best materials for separating a mixture of gases. We will present and discuss here experimental and Grand Canonical Monte Carlo (GCMC) simulation results of the behavior of CO2 molecules captured on functionalized silicas. Simulations are used to get additional insights into the adsorption process. We calculate the different adsorption sites and the orientation and distribution of the adsorbed molecules. The understanding of those processes plays a key role on further optimization of the synthesis of these materials. Results for materials for CO2 capture at high temperatures, such as improved calcium carbonate, and utilization of these materials in different applications will also be presented.

(a) (b)

Figure 1: (a) Example of functionalization of a silica surface by reaction with 3-amino propyl trimethoxysilane; (b) the same surface simulated by us using a dual-cutoff coupled-decoupled configurational bias Monte-Carlo (DC-CD-CBMC) [4]. This work is part of a CENIT project SOST-CO2 belonging to the Ingenio 2010 program financed by CDTI, Science and Innovation Department, Spanish Government, aiming at reducing the emissions of CO2 in Spain by and developing new industrial and sustainable uses of CO2. The project is lead by the company Carburos Metálicos, from Air Products Group, and it comprises 14 other companies and 29 research institutions. Support for this work from Air Products and the Spanish Government through project CEN-2008-1027 (CENIT SOST-CO2) is gratefully acknowledged. Additional support was provided by the Spanish Government (project CTQ2008-05370/PPQ) and by the Catalan Government (2009SGR-666 and two TALENT projects – to S. Builes and R. Ramirez, respectively). References [1] H. Bai, A.C. Yeh, Ind. Eng. Chem. Res. (1997), 36, 2490. [2] L.F. Vega, “CO2 as a resource: from capture to industrial uses”, Technical and Environmental Guides, 19, Fundación Gas Natural, ISBN: 978-84-614-1195-5. [3] J.C. Hicks, J. H. Drese, D.J. Fauth, M.L. Gray, G. Qi, C.W. Jones, J. Am. Chem. Soc. (2008), 130, 2902. [4] M.G. Martin, J.I. Siepmann. J. Phys. Chem. B (1999), 103 (21), 4508.


Surfactant based separation processes: thermodynamic aspects

Smirnova I.

Hamburg University of Technology

[email protected]

This talk is related to the investigation of phase equilibria in multicomponent micellar solutions with the aim to optimize surfactant based separation processes, like micellar extraction and micellar chromatography. Both methods are well known for the separation and analysis of products from aqueous systems and are based on the formation of aggregates of different size and shape (micelles) in aqueous solutions. The partition of target molecules is mainly caused by hydrophobic and electrostatic interactions between the micelles and the solute. The most relevant factor is the partition coefficient of all related species, which defines the selectivity of the process. Efficient separation processes can be designed if an appropriate surfactant or surfactant combination is selected for a multi component system. The dominating factors influencing a micellar separation process are the surfactant itself, its concentration, the characteristics of the solute, the pH-value of the solution and the ionic strength. Effective processes need fully optimized systems, however the vast amount of parameters need a theoretical description and modeling of the present interactions.

In our institute the optimization of the separation processes is realized based on the predictive thermodynamically based modeling of the solute partitioning. The partitioning of a variety of solute classes in aqueous solutions of nonionic and ionic surfactants under different experimental conditions is investigated with the a-priori quantum chemistry based model, COSMO-RS. It is demonstrated that the prediction can be achieved quantitatively based solely on the chemical structure of the substances. Furthermore, COSMO-RS model accounts for the concentration of each ingredient, ionic strength, and dissociation of the compounds at corresponding pH. Regarding the vast amount of different parameters like the influence of e. g. buffers, salts and alcohols in situ predictions using COSMO-RS is an effective tool to optimize surfactant based separation processes.

Further, the modeling is extended for other types of liquid-liquid equilibria, especially in the field of drug delivery and biotechnology. Modelling of the product isolation from the biotechnological production based on salt/sugar induced liquid-liquid phase split is discussed.

Invited Lecture


Desulfurization of Fuel Oils by Solvent Extraction with Ionic Liquids

Francisco M.

Department of Chemical Engineering, University of Santiago de Compostela, E-15782, Santiago de Compostela, Spain

[email protected]

In this work, feasibility of three imidazolium-based ionic liquids, namely 1-octyl-3-methylimidazolium tetrafluoroborate ([C8mim][BF4]), 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C8mim][NTf2]), and 1-ethyl-3-methylimidazolium ethylsulfate ([C2mim][EtSO4]), and of a polysubstituted pyridinium ionic liquid, 1-hexyl-3,5-dimethylpyridinium bis(trifluoromethylsulfonyl)imide ([C6mmPy][NTf2]), as solvents for extraction of sulfur- and nitrogen-containing compounds from fuels has been studied. Extraction power of these four ionic liquids has been tested by studying liquid-liquid equilibria and a three-step extraction process of both synthetic model oils and real fuels previous to the hydrodesulfurization (HDS) process in a refinery.

From the obtained liquid-liquid equilibrium data it can be concluded that these four ionic liquids are able to extract sulfur-containing compounds from fuels. Best results in terms of solute distribution ratios (β) were found for [C6mmPy][NTf2], but [C2mim][EtSO4] showed the highest values for selectivity (S). Solubility of aromatic compounds represented by toluene was high for all the studied ionic liquids. This means that a certain degree of aromatic compounds extraction can be predicted simultaneously to desulfurization process. These results indicate that in the case of a practical application a compromise between desulfurization and dearomatization must be achieved in order to comply with transportation fuel specifications and keep the octane number of gasoline. All four pyridine-containing ternary systems studied showed high values for selectivity and solute distribution ratio, indicating that denitrogenation could be easily reached with any of these ionic liquids.

Liquid-liquid equilibrium data of the ternary systems studied were correlated by means of the NRTL and UNIQUAC equations. In general, satisfactory results were found, and no conclusions could be established about what the best model is to correlate liquid-liquid equilibrium data of these ionic liquid-containing systems. When the simultaneous correlation of the ternary systems studied involved in gasoline and diesel desulfurization was carried out with these models, relatively large deviations were found, with UNIQUAC giving slightly better results than the NRTL model.

Results found in model oil extraction are in agreement with what could be expected from liquid-liquid equilibrium data. In the case of gasoline, the desulfurization yield for the four ionic liquids studied ranks as [C6mmPy][NTf2] > [C8mim][BF4] ≥ [C8mim][NTf2] > [C2mim][EtSO4], and in the case of the diesel model oil as

PhD award


[C6mmPy][NTf2] > [C2mim][EtSO4] > [C8mim][NTf2] > [C8mim][BF4]. The ionic liquid [C6mmPy][NTf2] showed the largest desulfurization capacity. Besides desulfurization, complete denitrogenation with all of the ionic liquids tested was achieved in the first stage of extraction for diesel models, and in the second stage for the case of gasoline, except with [C2mim][EtSO4], which needed a third extraction step. Desulfurization and denitrogenation were also accompanied by dearomatization. In all the extractions performed with these model oils, the ionic liquid composition in the raffinates was undetectable.

Parallel results to those with model oils were found for real oil samples, namely light naphtha and diesel obtained previous to the current desulfurization process in refinery streams, when analyzing sulfur reduction in the three-step extraction. This ensures that in the case of [C6mmPy][NTf2] and [C2mim][EtSO4], no ionic liquid is solubilized in the hydrocarbon phase because, if that would have happened, inherent sulfur content of these solvents would have increased the total sulfur content of samples.

Among all the ionic liquids studied, [C6mmPy][NTf2] seems to be the most suitable candidate to carry out fuel desulfurization. Simulation of the extraction process using available process-software confirms the capacity of this ionic liquid to reach desulfurization levels in accordance with legislation requirements. Nonetheless, due to the order of deviations found with the correlation equations, this can only be understood as a qualitative simulation exercise. Pilot plant testing, economical studies, life cycle assessment, etc., are necessary steps to continue this study.


Sunday, 26.06.2011

SESSION 7: Surfactants, Polymers and Bio-Related Systems


Enthalpy and entropy driven phase transitions in surfactant and lipid systems

Kocherbitov V.

Malmö University, Sweden

[email protected]

Various liquid crystalline phases can be formed in surfactant and lipid systems. Formation of a particular liquid crystalline phase depends on the conditions of the experiment, especially temperature and water content.

According to so-called “natural” phase sequence, the phases with higher curvatures are formed at higher water contents. At higher water contents the headgroups are aggregated with larger number of water molecules than at lower water contents. This makes higher curved structures more energetically favorable at higher water contents. On the other hand, there are exceptions from the natural phase sequence, such as monoolein - water system. In this system a reverse cubic phase is formed from the lamellar phase upon increase of the water content.

In order to find the driving forces of phase transitions in surfactant and lipid systems we have performed systematic studies of several classes of surfactants and lipids using the method of sorption calorimetry. The sorption calorimetry allows resolving the enthalpic and the entropic contributions of the hydration processes at a constant temperature and thus provides direct information about the driving forces of hydration-induced phase transitions.

Summarizing the results of the studies of several systems we concluded that the phase transitions to structures with higher curvatures are driven by enthalpy, while the phase transitions to structures with lower curvatures are driven by entropy. From the chemical thermodynamics of binary systems it follows that the isothermal phase transitions can be driven either by enthalpy or by entropy, but not by the both potentials simultaneously. It implies that the transitions to the liquid crystalline phases with lower curvatures are enthalpically unfavourable and occur only because of the entropic reasons. The main part of the entropy contribution for such transitions is provided by the hydrocarbon tails.

The driving forces of the phase transitions can also be obtained from the thermodynamic analysis of slopes of the phase boundaries in binary phase diagrams1 using the van der Waals differential equation. The approach presented here was experimentally tested on several classes of surfactants and lipids such as sugar surfactants2,3, polyethylene oxide surfactants, DDAO4, monoolein and others.

An approach that combines the theory of driving forces of phase transitions with modeling of surfactant and lipid aggregates is currently under development.


References [1] Kocherbitov, V. Driving forces of phase transitions in surfactant and lipid systems. J. Phys. Chem. B. (2005), 109, 6430-6435. [2] Kocherbitov, V.; Söderman, O.; Wadsö, L. Phase Diagram and Thermodynamics of the n-Octyl beta-D-Glucoside/Water System. J. Phys. Chem. B. (2002), 106 (11): 2910-2917 [3] Kocherbitov, V.; Söderman, O. Phase diagram and physicochemical properties of the n-octyl alpha-D-glucoside/water system. PCCP. (2003), 5 (23), 5262-5270. [4] Kocherbitov, V., Söderman, O. Hydration of Dimethyldodecylamine-N-Oxide: Enthalpy and Entropy Driven Processes. J.Phys.Chem.B. (2006), 110, 13649-13655


A multiscale method for the prediction of the volumetric and gas solubility behavior of high-Tg polymers

Minelli M.1, Heuchel M.2, De Angelis M.G.1, Hofmann D.2, Sarti G.C.1, Doghieri F.1

1 - Università di Bologna 2 - Helmholtz-Zentrum Geesthacht (HZG)

[email protected]

The description of gas and vapor solubility in glassy polymers is relevant for many practical applications, from membrane separations to packaging and from sensors development to medical instrumentation. In the last decade, a new macroscopic model has been developed based on thermodynamic analysis of non-equilibrium polymeric glasses [1], the NET-GP theory. This approach, combined with an equation of state (EoS) theory, such as the Lattice Fluid or SAFT, gives rise to the corresponding non-equilibrium models named NELF and NE-SAFT [2], respectively, able to predict solubility of gases and vapors in glassy polymers, with negligible consumption of CPU time. EoS characteristic parameters for the penetrants are normally retrieved fitting liquid-vapor equilibrium data for penetrants; for polymers, pressure-volume-temperature (pvT) data above Tg are required. Such data are available in the literature for low-Tg polymers [3], whereas for high-TG glassy polymers, such as polyacetylenes and many polyimides of extreme importance for membrane separation, these data are practically impossible to be measured, and the NET-GP model faces a serious limitation.

In this work, an atomistic approach is employed to simulate pvT data of polymers at high temperature (in the rubbery region), by using a molecular dynamics tool. Data are then regressed with the desired EoS to obtain the polymer characteristic parameters, which are used to evaluate the gas solubility in the polymer with NET-GP model.

Two different polyimides, Polyetherimide (Ultem® 1000) and poly(4,4’-oxydiphenylenepyromellitimide) (Kapton® H), were selected to test the method feasibility: for Ultem®, experimental pvT data are available [3] and can be used to validate the method.

For both polymers, three independent atomistic models (a single chain of 70-80 repeat units, about 5000 atoms, for methodology see e.g. [4]) were created with Materials Studio software by Accelrys. Isobaric curves at different pressure have been simulated in a NpT ensemble ranging from 200 K up to 900 K with a COMPASS force field.

For Ultem®, MD simulations are in good agreement with experimental pVT data, especially at the higher temperatures. In the case of Kapton, pVT data are not experimentally available and the results from simulations allowed the calculation of the characteristic parameters of both LF and PC-SAFT EoS models. NELF and NE-SAFT models were then employed to predict rather accurately the sorption isotherms of different penetrants, as reported in Figure 1 for CO2

sorption.


Figure 1. CO2 sorption isotherms, experimental data from [5] and NE-PC-SAFT with the Kapton characteristic parameters obtained from simulations.

References [1] F. Doghieri, G.C. Sarti, Macromolecules 29 (1996) 7885. [2] F. Doghieri et al. Desalination 144 (2002) 73. [3] P. Zoller et al. Standard Pressure-Volume-Temperature Data for Polymers, Technomic, Lancaster, 1995. [4] M. Heuchel et al. Macromolecules 37 (2004) 201-214. [5] I. Okamoto et al. J.Polym.Sci.: PartB: Polym.Phys. 27 (1989) 643-654.


Predicting thermodynamic properties of Hyperbranched Polymers

Völkl J., Arlt W.

University Erlangen-Nuernberg Chair of Separation Science and Technology

[email protected]

For the development of optimised processes the design of task specific solvents is a promising approach. A suitable class of substances for this purpose are hyperbranched polymers. Their structure can be made up from different building blocks, by which the desired macroscopic properties of the molecule can be tailored [1]. The thermodynamic behaviour can be modelled and predicted by group-contribution methods like UNIFAC-FV [2]. Another possibility is the use of the quantum mechanics based method Conductor-like Screening Model for Real Solvents (COSMO-RS) for the a-priori estimation of the thermodynamic behavior of hyperbranched polymers. The only required input data is the molecular structure of the polymer. The density functional theory (DFT) and the continuum model COSMO are used to calculate the electron density distribution of the molecule. Then the chemical potential can be calculated with statistical thermodynamics (COSMO-RS). In this work the COSMO-RS model was successfully applied for hyperbranched polymers. It focuses on two main aspects. First, a procedure was developed, with which the needed calculation times for large molecules like hyperbranched polymers can be minimised, while the prediction quality is kept high. The structure of the polymer was divided in subunits. Each unit was optimised in the quantum mechanics calculations. In the COSMO-RS step the subunits were assembled again. The quality of the thermodynamic calculations depends on the number and size of the subunits. It was shown that larger subunits lead to better results. Second, the approach was applied to predict the influence of hyperbranched polymers on the VLE of ethanol and water, and to predict the solubility of carbon dioxide. The results were compared to experimental data [1,2]. The model COSMO-RS can describe these systems very well. The role of the polymer as entrainer was predicted as well as the influence of the amount of polymer and the molecular structure on the VLE of water-ethanol. A qualitative prediction of the carbon dioxide in pure polymers and in aqueous solution was also possible with COSMO-RS. The model is limited to physical solvents and cannot be used for reacting systems. However the COSMO-RS approach is able to be used in computer aided design of tailor-made hyperbranched polymers in chemical engineering.

References [1] M. Seiler, Dissertation, University Erlangen-Nürnberg, 2004 [2] J. Rolker, M. Seiler, L. Mokrushina, W. Arlt, Ind. Eng. Chem. Res. 2007, 46, 6572-6683


Stability of polystyrene latex suspended in water at high pressure and high temperature

Kostko A.F.1, McHugh M.A.2

1 - Department of Physics, St. Petersburg State University of Refrigeration and Food Engineering, 9 Lomonosov Str., St. Petersburg 191002, Russia

2 - Department of Chemical and Life Science Engineering, Virginia Commonwealth University, 601 West Main Street, Richmond, Virginia 23284, USA

[email protected]

Dynamic light scattering (DLS) measurements of Brownian particles, suspended in a liquid, provide a means to measure the viscosity of the liquid. This technique is a facile method for viscosity measurements at high pressure [1,2] as long as the probe particles remain stable and do not aggregate. We use DLS to investigate the behavior of dilute aqueous suspensions of polystyrene latex nanoparticles at pressures to 220 MPa and high temperatures to ascertain the reliability of this technique for viscosity measurements at extreme operating conditions. Alargova et al. [1] investigated the stability of dilute aqueous polystyrene latex solutions at pressures below 28 MPa and found that the latex suspension remains stable at temperatures below 275 °C. In the present study we extend the pressure range of the Alargova study to P<220 MPa using the DLS apparatus described in [3]. Our DLS measurements of the diffusion coefficient, D, were performed at 21, 110, 120, 130, and 180 °C with aqueous solutions of polystyrene particles (diameter 87 nm, as reported by the manufacturer). Water viscosities, ηDLS, were calculated as ηDLS = (kT)/(6πRD), where k is Boltzmann’s constant, T is the absolute temperature, and R is the mean radius of the polystyrene particles. Figure 1 shows viscosity values obtained in the present study reduced by the water viscosity obtained from the NIST Chemistry WebBook [4] at each corresponding pressure and temperature. The experimental data exhibit a satisfactory correlation with the standard viscosity over the entire operating range shown in the figure. At a higher temperature and pressure, namely, T = 215 °C and P = 203 MPa, the suspension became unstable and the diffusion coefficient began to decrease with time, indicating aggregation of the particles.


0 50 100 150 200 2500.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

21 Co (14-17 MPa) 110 Co (14-220 MPa) 120 Co (14-152 MPa) 130 Co (7-110 MPa) 180 Co (14-70 MPa)

η DLS

/ηN

IST

P (MPa) Figure 1. Water viscosity measured with DLS (this study) reduced by viscosity values obtained from the NIST WebBook at various pressures and temperatures.

The results obtained in the present study show that polystyrene latex particles begin to aggregate at temperatures lower than 275 °C as found by Alargova et al. [1] if the pressure is increased significantly above 28 MPa. However, at T = 110 C° polystyrene latex aqueous system remains stable, at least, up to P = 220 MPa. This fact has been used in our study of concentrated aqueous Pluronic® system reported in Ref. [3].

References [1] R. G. Alargova, S. Deguchi and K. Tsujii, Colloids Surf. A, (2001), 183-185, 303–312. [2] G. Meier, R. Vavrin, J. Kohlbrecher, J. Buitenhuis, M. P. Lettinga and M. Ratajczyk, Meas. Sci. Technol., (2008), 19, 034017. [3] A. F. Kostko, J. L. Harden and M. A. McHugh, Macromolecules, (2009), 42, 5328–5338. [4] E. W. Lemmon, M. O. McLinden and D. G. Friend, "Thermophysical Properties of Fluid Systems" in NIST Chemistry WebBook, NIST Standard Reference Database Number 69, Eds. P.J. Linstrom and W.G. Mallard, National Institute of Standards and Technology, Gaithersburg MD, 20899, http://webbook.nist.gov.


0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

1

-4.6 -4.4 -4.2 -4 -3.8 first moment (eV)

frozen

quench

comp

release

0.9

New description of structural disorder in glass based on statistical thermodynamics

Takada A.1,2,3, Richet P.4, Atake T.5

1 - The University of Tokyo 2 - University College London

3 - Asahi Glass Company 4 - Institut de Physique du Globe de Paris

5 - Tokyo Institute of Technology

[email protected]

It is well known that glasses with different annealing profile and/or different pressure profile show different properties. The authors have recently proposed new methodology on new description of structural disorder in glass based on thermodynamics [1-2]. The interaction energies calculated by Molecular dynamics (MD) are analyzed in terms of ‘atomistic energy distribution’ (AED) with which pair-interaction energies are divided into equal halves allocated to each atom. Therefore, each atom has the summed-up value (‘atomistic potential energy’) of half the pair-interaction energies. The calculated results show different patterns and profiles in first and second moments of AED in silica glasses with different annealing profile and/or different pressure profile shown in Fig.1. Finally, it is suggested that these moments can be used as order parameters for glasses and liquids.

Figure 1. Correlation of first and second moments of AED in glass References [1] A. Takada, P. Richet, T. Atake, J. Non-Cryst. Solids (2009) 355, 694-699. [2] A. Takada, P. Richet, T. Atake, J. Non-Cryst. Solids (2010) 356, 2486-2491.

second moment (eV2)


Properties of pharmaceutical cocrystals generated by supercritical fluids

Padrela L., Rodrigues M., Duarte T., Matos H.A., De Azevedo E.G.

Instituto Superior Técnico

[email protected]

Pharmaceutical cocrystals have been attracting an increased interest from both the academic and industrial environments due to their improved physicochemical properties (e.g. solubility, stability, bioavailability) compared to the pure APIs (active pharmaceutical ingredients). Cocrystals provide good alternative solutions to other forms of APIs such as polymorphs, salts or solvates/hydrates [1, 2].

The potential of supercritical fluids (SCFs) as new media for the cocrystallization of APIs has been addressed recently in the literature by our group [3, 4]. Different supercritical fluid techniques can be used to produce cocrystals by using different supercritical fluid properties (solvent, anti-solvent or atomization enhancement), bringing additional advantages compared to the classical cocrystal production methods.

In this work we present the results from three different supercritical techniques: Cocrystallization with Supercritical Solvent (CSS), Supercritical Anti-Solvent (SAS) and Supercritical Enhanced Atomization (SEA). Each technique explores the ability of supercritical CO2 to aid in the interaction between an API (e.g. indomethacin, theophylline, caffeine, carbamazepine) and a cocrystal former (e.g. saccharin). The thermodynamic and kinetic particularities for successful cocrystal formation in each supercritical fluid technique will be discussed. Phase equilibria conditions for the precipitation/crystallization of each API and cocrystal from supercritical CO2 (in the case of CSS technique) and/or organic solvents (in the case of SAS and SEA techniques) will be shown.

The potential cocrystalline phases of the collected samples were characterized by DSC (Differential Scanning Calorimetry), PXRD (Powder X-Ray Diffraction), SEM (Scanning Electron Microscopy) and HPLC (High Performance Liquid Chromatography). As Figures 1 and 2 show, the PXRD patterns and DSC thermograms of TPL-SAC cocrystals generated by supercritical fluid techniques are distinct from the pure drugs. The physicochemical properties of these cocrystals and others, such as solubility, dissolution rate and stability will be presented.


Figure 1. PXRD diffractograms of (a) pure theophylline, (b) pure saccharin and (c) theophylline-saccharin cocrystals processed by the CSS technique.

Figure 2. DSC heating curves of pure theophylline, (a), pure saccharin (b) and TPL-SAC cocrystals (c) produced by the CSS technique.

References [1] D. R. Weyna, T. Shattock, P. Vishweshwar, M. J. Zaworotko, Cryst. Growth Des., (2009), 9, 1106-1123. [2] S. Basavoju, D. Bostrom, P. S. Velaga, Pharm. Res., (2007), 25, 530. [3] L. Padrela, M. A. Rodrigues, S. P. Velaga, H. A. Matos, E. G. Azevedo, Eur. J. Pharm. Sci., (2009), 38, 9-17. [4] L. Padrela, M. A. Rodrigues, S. P. Velaga, A. C. Fernandes, H. A. Matos, E. G. Azevedo, J. Supercrit. Fluids, (2010), 53, 156.


Aqueous Solubility of Pharmaceuticals at Different pH

Cassens J., Prudic A., Ruether F., Sadowski G.

Laboratory of Thermodynamics, Department of Biochemical and Chemical Engineering,TU Dortmund, Emil-Figge Str. 70, D-44227 Dortmund, Germany

[email protected]

The solubility of pharmaceuticals in solvents and solvent mixtures is an important property for designing crystallization processes. The PC-SAFT equation of state (EOS) has already been successfully used to describe the solubility of various drug substances and intermediates in solvents as well as in solvent mixtures.

Many pharmaceutical compounds contain acidic or basic functional groups which can be ionized in order to enhance the solubility in water. For example, the aqueous solubility of the pharmaceutical base lidocaine can be raised significantly by adding an acid (HCl) to the solution (Figure 1) which leads to a change of pH-value in the solution.

Figure 1: Aqueous solubility of lidocaine at different pH at 25°C (HCl was added to the solution). In this work the aqueous solubility of three drug compounds at different pH was measured. Moreover, an approach to model the pH-dependent solubility of pharmaceuticals by applying PC-SAFT model was developed. In the model the activities of the ionic species and the electrostatic interactions based on the Debye-Hueckel theory were taken into account. Furthermore, the salt formation was explicitly considered. The calculation results were compared to experimental data to demonstrate the applicability of the proposed model.


Sunday, 26.06.2011

SESSION 8: Phase Equilibria and Thermophysical data: measurement, analysis and predictive tools


Phase Equilibria for the Recovery of Monoglycerides from Fatty Esters using Near Critical CO2+Propane Mixtures

Hegel P.E., Vélez A., Pereda S., Mabe J., Brignole E.A.

PLAPIQUI-Universidad Nacional del Sur-CONICET, Camino La Carrindanga km. 7, Bahia Blanca, Argentina

[email protected]

The production of biodiesel or fatty esters from lipids with non-catalytic Supercritical Methanol (SC-MeOH) has gained interest in the last decade because it allows the processing of waste vegetable oils, crude oils and fats, with high concentration of fatty acids and water[1]. Monoglycerides (Mg), diglycerides (Dg), and glycerol are the main by-products that can be obtained in the transesterification process when there is a partial reaction of transesterification. Acylglycerols constitute a very common food emulsifiers and they have been used as surface active agents in many industrial cleaning products. Mixtures of CO2+C3 have a good selectivity for the separation of Fatty Esters (FE) from glycerides because it is possible to obtain liquid-liquid equilibria at different operating conditions of temperature, pressure and solvent concentration. Solvent mixtures of carbon dioxide + propane (CO2+C3) were previously studied to analyze the extraction and separation of vegetable oils with dense gases [2,3].

The aim of this work is to study the phase equilibria of the transesterification reaction products, with CO2 + propane mixtures, in order to design a feasible reaction and separation process for the production of fatty esters and monoglycerides. This technology would have direct application, for example, in the separation steps of the biodiesel obtained from low cost vegetable oils.

For example the biodiesel obtained with SC-Methanol at 280 °C and 90 bar in 25 min. of reaction time with an initial molar ratio of 10:1 (MeOH to soybean oil) presents a 70 % of FE by weight fraction. The chromatographic analysis of the oil phase obtained in these experiments indicate that Mg are clearly the main by-product that is obtained together with Dg and triglycerides (Tg) in minor quantities.

Predictions with the GCA-EOS model of the phase behavior of the system (CO2+C3, 25 wt.% of CO2) + Mg + FE at 25 bar and 298.1 K indicate that an initial mixture of Mg + FE with 30 % wt. of Mg would split into two liquid phases when it is mixed with a 42 % by weight fraction of solvent. The light liquid phase formed has a content of 97 wt. % of FE in the oily phase after the solvent separation. From the point of view of safety, both liquid phases present a concentration of CO2 greater than 19 wt.% which results in a non-flammable vapor phase. Therefore the presence of CO2 is increasing the safety and selectivity of the process.

In the present work experimental data on phase equilibria of the biodiesel products obtained by SC-MeOH (FE + Mg) and mixtures of propane + CO2 have been measured


in a windowed variable volume cell under conditions of liquid-liquid-vapor equilibria for a constant CO2 / propane ratio. The thermodynamic model combined with reliable experimental information can be used to generate suitable phase scenarios for the design of safer and more efficient separation process of esters and monoglycerides with direct application in the biodiesel production.

References [1] R. Sawangkeaw, K. Bunyakiat, S. Ngamprasertsith, J. of Supercritical Fluids, (2010), 55, 1–13. [2] S. Peter, U. Ender, Fat Science and Technology, (1989), 91, 260. [3] P. Hegel, G. Mabe, S. Pereda, M. Zabaloy, E. Brignole, J. of Supercritical Fluids (2006), 37, 316–322.


Fluid phase behavior of trifluoromethane + phenylalkanes

Bogatu C.1, Geana D.2, Poot W.3, De Loos T.W.3

1 - Transilvania University of Brasov, The Centre Product Design for Sustainable Energy, 50 Iuliu Maniu Street, Romania

2 - Politehnica University of Bucharest, Faculty of Applied Chemistry and Materials Science, Applied Physical Chemistry and Electrochemistry Dept., Bucharest, Romania

3 - Delft University of Technology, Process and Energy Department, Laboratory for Engineering Thermodynamics, Delft, The Netherlands

[email protected]

In this study, the phase behaviour of asymmetric systems consisting of the refrigerant, trifluormethane (R23) and 7 members of the family of the alkylbenzenes is investigated. Alkylbenzenes are used as lubricants in refrigeration cycles for special applications at very low temperature.

Equilibrium data were obtained using a synthetic method in the temperature range 250…400 K and in the pressure range 1.5…15 MPa. The investigated systems all exhibit type III phase behaviour, according to the classification of van Konynenburg and Scott, except for the system CHF3+i-propylbenzene, which is of type II. For 4 systems the experimental data were modelled with two cubic EoSs: Soave-Redlich-Kwong (SRK) and Peng-Robinson (PR) and coupled with classical van der Waals mixing rules. A single set of binary parameters was used to predict the global phase behaviour of the system for a large range of pressure and temperature. Although the model is simple, it is able to represent correctly the complex phase equilibria of the system studied in this work.


Diffusion coefficients of aqueous KCl at high pressures measured by the Taylor dispersion method

Secuianu C.1,2, Maitland G.C.1, Trusler J.P.M.1

1 - Qatar Carbonates and Carbon Storage Research Centre (QCCSRC), Department of Chemical Engineering, Imperial College London, South Kensington Campus, SW7 2AZ, London,

UNITED KINGDOM 2 - Department of Applied Physical Chemistry and Electrochemistry, Faculty of Applied

Chemistry and Materials Science, “Politehnica” University of Bucharest, 1-7 Gh. Polizu Street, 011061 Bucharest, ROMANIA

[email protected]

Measurements of thermophysical properties in systems containing carbon dioxide, hydrocarbons, brines and mineral at reservoir conditions are being undertaken as part of a wide-ranging programme. This research is directed towards improved understanding of the detailed physical and chemical processes occurring at the pore and fracture scale in carbonate reservoirs during water and gas injection processes, including both geological storage of CO2 and CO2-enhanced hydrocarbon production [1]. As a part of this programme, an analytical apparatus was designed and built to measure diffusion coefficients for systems containing carbon dioxide and/or hydrocarbons and/or brines at temperatures up to 473 K and pressures up to 70 MPa. The method used is the chromatographic peak broadening technique based on the fundamental work of Taylor [2,3], later extended by Aris [4], which involves the dispersion of a solute injected into in a steady-state laminar flow of a mobile solvent phase through a long tube of uniform diameter. Due to the combined effects of convective flow and molecular diffusion, the initially sharp pulse develops a Gaussian distribution. The temporal variance of this Gaussian distribution is dependent on both the average flow velocity and the molecular diffusivity. At the end of the diffusion tube, the concentration is measured as a function of time. In the present work, this was accomplished by means of a chromatographic refractive-index detector. In order to confirm the accuracy of the new apparatus, the diffusion coefficient D12 of aqueous potassium chloride solutions was measured at ambient pressure and T = 298.15 K. Figure 1 shows a typical signal observed at the detector for a 1 M aqueous KCl solution. From the fitting of the experimental curve, the diffusion coefficient was determined and compared with data from the literature [5,6]. The value of the diffusion coefficient found with the new apparatus for a 1 M KCl solution at T = 298.15 K is 1.8580·10-9 m2·s-1, while the literature value is 1.8585·10-9 m2·s-1; the difference is smaller than 0.5%. To permit measurements at high pressures a set of short restrictor tubes of small internal diameter were used between the diffusion tube and the chromatographic detector. This permitted the diffusion to occur at high pressure but detection to be carried out at or near ambient pressure.


Using this method, further measurements have been made over a wide range of temperatures and pressures for various finite concentrations of aq KCl and the results at T = 298.15 K are shown in Figure 2. Data at such elevated pressures are not available in the literature.

Figure 1. Comparison of experimental refractive index n measured as a function of time t with the model at T = 298.15 K and p = 0.1 MPa for 1 M aq KCl.

-1000

0

1000

2000

3000

4000

5000

6000

7000

8000

0 500 1000 1500 2000 2500 3000t/s

109 n

expmodel

Figure 2. Diffusion coefficients for 1 M aq KCl as a pressure function

1.9100

1.9150

1.9200

1.9250

1.9300

1.9350

1.9400

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1.9500

0 20 40 60 80P/MPa

109 D

12, m

2 /s

T = 298.15 K

In order to make measurements for CO2 dissolved in brines or hydrocarbons, it will be necessary to operate with the detector at high pressures and our present efforts are directed towards modifying the refractive-index device for that purpose. References [1] http://www3.imperial.ac.uk/qatarcarbonatesandcarbonstorage [2] G. Taylor, Proc. Royal Soc. London, (1953), A219, 186-203. [3] G. Taylor, Proc. Royal Soc. London, (1954), A225, 473-477. [4] R. Aris, Proc. Royal Soc. London, (1956), A235, 67-77. [5] Experimental Thermodynamics. Vol. III. Measurement of the Transport Properties of Fluids. Eds. A. Nagashima, J.V. Sengers and W.A. Wakeham.Blackwell Scientific Publications (1991). [6] L.A. Woolf, J.F. Tilley, J. Phys. Chem., (1967), 71(6), 1962-1963.


Thermodynamics of Perfluoroalkylalkanes: liquid, surface and transport properties

Morgado P.1, Filipe E.J.M.1, Rodrigues H.1, Martins L.F.G.2, Blas F.3, McCabe C.4

1 - Centro de Química Estrutural, Instituto Superior Técnico, 1049-001 Lisboa, Portugal 2 - Centro de Química de Évora, Universidade de Évora, 7000-671 Évora, Portugal

3 - Departamento de Física Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, 21071 Huelva, Spain

4 - Department of Chemical Enginering, Vanderbilt University, Nashville, Tennessee 37235, USA

[email protected]

It is well known that alkanes and perfluoroalkanes tend to demix. Perfluoroalkylalkanes (PFAA), also known as semifluorinated alkanes (SFA), are molecules in which a fluorocarbon chain is chemically linked to a hydrocarbon chain, CF3(CF2)n(CH2)mCH3. PFAA thus behave as chemical mixtures of alkanes and perfluoroalkanes (that given their mutual phobicity would otherwise phase separate) while exhibiting the dual character of amphiphiles. Additionally, display the properties characteristic of fluorinated solvents, such as inertness, biocompatibility and the ability to solubilize high levels of respiratory gases. They are known to auto-organize in different media and interfaces, to aggregate in solvents selective for one of the blocks and to form smectic liquid crystalline phases and nanopatterned molecular films1. PFAA are used for medical applications as components of liquid ventilation emulsions and temporary blood substitutes formulations and as fluids in eye surgery. We have systematically measured a number of thermophysical properties of liquid PFAA, such as liquid densities2, vapour pressures, viscosities and surface tensions, as a function of temperature, pressure and relative length of the hydrogenated and fluorinated chains. The solution behaviour of PFAA in hydrogenated solvents3,4 and the solubility of water and respiratory gases in liquid PFAA were also studied. The results have been interpreted using molecular dynamics simulations and a “hetero” version of the SAFT-VR theory. A fully predictive approach has been developed in which all parameters needed to describe the alkyl and perfluoroalkyl segments (m, ε, σ and λ), including the binary interaction parameters (ξij and γij) necessary to account for the inter and intramolecular interactions, were taken from earlier work on the alkanes, perfluoroalkanes and their mixtures5. References 1A. L. Simões Gamboa, E. J. M. Filipe, and P. Brogueira, Nano Lett. 2002, 2, 1083-1086. 2Morgado et al., J. Phys Chem B 2007, 111, 2856-2863. 3Morgado et al., J. Phys. Chem. C 2007, 111, 15962-15968. 4Morgado et al., submitted to Fluid Phase Equilibria 5Morgado et al., Fluid Phase Equilibria 2005, 228, 389–393.


Thermophysical properties of Shell Normafluid over extended ranges of temperature (243-423 K) and pressure (0.1-200

MPa)

Chorążewski M.1,2, Grolier J.-P.E.2

1 - Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice, POLAND 2 - Laboratory of Thermodynamics of Solutions and Polymers, University Blaise Pascal,

Clermont-Ferrand, FRANCE

[email protected]

Thermodynamics properties of fuels are of practical importance in engineering work associated with optimization of the design of high pressure Diesel injectors and of their efficiency in combustion engines. Shell Normafluid V-Oil1404 is a standardised fluid for testing and calibrating diesel fuel injectors equipment for the high pressure-direct gasoline injection. This calibration fluid meets the requirements of ISO 4113 and SAE J 967 standards. Direct determinations of isobaric thermal expansivities of a Shell Normafluid have been made at different temperatures from 243 to 423 K and at different pressures from 0.1 to 200 MPa. The experimental technique, Scanning Transitiometry [1-4], has been operated in conjunction of an ultracryostat to work at temperature below 273 K. Experimentally, following the scanning transitiometry principle measurements were taken along isotherms, when decreasing the pressure by steps from an initial high pressure, according to the equation:

pQα =

V T ∆p−

where Q - is the energy developed in the substance under investigation by the pressure step ∆p and V is the volume of the substance contained in the calorimetric vessel. Interestingly, for a Shell 1404 the single crossing point of isobaric thermal expansivity isotherms is well observed. Other important thermophysical properties have been evaluated using our isobaric thermal expansivities. The derived properties include isothermal compressibilities and isobaric heat capacities. Heat capacities can then be used in the evaluation of other basic thermodynamic properties of the fuel. The study was carried out under the project EJ 3199 Agreement N° 08 2 90 6382 - NADIA-bio (New Advance Diesel Injection Diagnosis for bio fuels). Direction Générale des Entreprises, France, Ministère de l’Economie, de l’Industrie et de l’Emploi.

References [1] S. L. Randzio, J-P. E. Grolier, J. R. Quint, D. J. Eatough, E. A. Lewis, L. D. Hansen, Int. J. Thermophys., 15, 415-441 (1994). [2] S. L. Randzio, Chem. Soc. Rev., 25, 383-392 (1996). [3] J-P. E. Grolier, F. Dan, S.A.E. Boyer, M. Orłowska, S.L. Randzio, Int. J. Thermophys., 25, 297-319 (2004). [4] S. L. Randzio, D. J. Eatough, E. A. Lewis, L. D. Hansen, J. Chem. Thermodynamics, 20, 937-948 (1988).


Dynamic Web-based Data Dissemination through Web Thermo Tables

Kroenlein K., Muzny C.D., Diky V., Kazakov A., Chirico R.D., Magee J.W., Abdulagatov I., Frenkel M.

Thermophysical Properties Division, National Institute of Standards and Technology, Boulder, Colorado 80305-3337, USA

[email protected]

The Dynamic Data Evaluation concept involves coupling expert-system software with comprehensive electronic databases in order to automatically generate property recommendations based on all available experimental and predicted data. This ability to generate critically-evaluated data ‘to order’ has been implemented in software [ThermoData Engine (TDE) desktop application] at the U.S. National Institute of Standards and Technology. With the recent rise of rich Web applications, we gained the capability to combine an inexpensive, effective and rapid channel for the transfer of information represented by the Internet with dynamic, distributed applications. In this presentation, we describe the result of combining the core software libraries of TDE with a dynamic Web interface, as implemented in Web Thermo Tables (WTT). This service delivers critical evaluations of pure compound properties, including critical properties, phase boundary equilibria, densities, energetic properties and transport properties. In addition, advanced visualization techniques are made accessible to users, including a system that caches evaluation results to maintain their high availability and an advanced window-in-window interface that leverages standard web-browser technologies. WTT is currently available to users in two editions: Professional (wtt-pro.nist.gov) covering more than 23,000 compounds and Lite (wtt-lite.nist.gov) covering 150 commonly used chemicals. Future extensions of the interface and associated web-services will be outlined.


Estimation of Properties of Pure Components Using Improved Group Contribution Based and Atom Connectivity

Index Based Models and Uncertainty Analysis

Hukkerikar A.1, Sarup B.2, Sin G.1, Gani R.1

1 - CAPEC, Department of Chemical and Biochemical Engineering, Technical University of Denmark, DK-2800, Lyngby, Denmark

2 - Vegetable Oil Technology Business Unit, Alfa Laval Copenhagen A/S, DK-2860, Søborg, Denmark

[email protected]

Pure component physical and thermodynamic properties are needed to carry out tasks such as product/process design and computer aided molecular design. While use of experimentally measured values for the needed properties are desirable, this is not feasible for many reasons. Therefore, efficient and reliable property prediction tools are necessary. The large gap between the number of compounds of interest and the data available for them, drives the interest for development of better and more versatile property prediction models. Among the group contribution methods for estimation of properties of pure compounds, the Marrero and Gani (MG) method (Marrero and Gani, 2001) is well-known. The MG method (i) allows accurate and reliable estimations; (ii) is able to distinguish among some isomers; (iii) is based on significantly large data-sets; and (iv) is based on large and comprehensive sets of groups. For the case where the molecular structure of a given compound is not completely described by any of the available groups, atom connectivity index based estimation method has been employed together with MG method to create the missing groups and to predict their contributions (Gani et al., 2005). This combined approach has led to the development of group contribution+ method of wider application range than before because the missing groups and their contributions are now easily obtained through the regressed contributions of connectivity indices.

The accuracy of product/process design and molecular design largely depends on the accuracy of the underlying physical and thermodynamic property information. Whiting et al (1993) have illustrated the effect of uncertainty in thermodynamic data and models on the process design through several examples and concluded that uncertainty analysis of property prediction models is essential for getting accurate and feasible solutions in process design, simulation, and optimization.

The objective of this work is to develop new and improved set of parameters for group contribution based and atom connectivity index based models to estimate properties of pure components together with uncertainty in the estimated property value. This includes: a parameter estimation step to determine the model parameters (group contributions / atom contributions and model constants) and an uncertainty analysis step to establish statistical information about the quality of parameter estimation, such as


covariance, standard error and confidence interval in the parameters and in the estimated property value. For parameter estimation, large data-sets of experimentally measured property values of a wide range of pure compounds are taken from the CAPEC database. Classical frequentist approach i.e., least square method was adopted for the estimation of model prediction uncertainty (Sin et al., 2010). Improved group and atom contributions along with the standard error and confidence intervals for MG based models have been obtained via regression for the following properties: normal boiling point, critical constants, standard enthalpy of formation, standard enthalpy of vaporization, standard Gibbs energy, normal melting point, standard enthalpy of fusion, entropy of vaporization, surface tension, viscosity, flash point, auto ignition temperature, Hansen solubility parameters, Hildebrand solubility parameter, aqueous solubility, octanol/water partition coefficient, compressibility factor, molar volume, molar refraction, refractive index and lethal concentration. The performance of predictive models for these properties with the new set of group and atom contributions is highlighted through a set of molecules not used in the regression step. The use of the new set of model parameters and quantification of uncertainty (prediction error) allows one to estimate property values with improved prediction accuracy and obtain rationally the risk/safety factors in product/process design.

References [1] G. Sin, A. Meyer, and K. Gernaey, Computers and Chemical Engineering, (2010), 34, 1385-1392. [2] J. Marrero, and R. Gani, Fluid Phase Equilibria, (2001), 183-208. [3] R. Gani, P. Harper, and M. Hostrup, Industrial and Engineering Chemistry Research, (2005), 44, 7262-7269. [4] W. Whiting, T. Tong, and M. Reed, Industrial and Engineering Chemistry Research, (1993), 32, 1367-1371.


Sunday, 26.06.2011

SESSION 9: Petroleum fluids


The NRTL-PR Equation for the Modelling of Synthetic Petroleum Fluids with Associating Compounds: Prediction of

Phase Envelopes and Influence of Lumping/Delumping Procedures

Neau E.1, Escandell J.1, Nicolas C.2

1 - Laboratory M2P2, UMR 6181, University of Méditerranée, Marseille, France 2 - Laboratory LMGEM, UMR 6117, University of Méditerranée, Marseille, France

[email protected]

Exploitation, in extreme conditions, of reservoir fluids containing water usually requires injection of associating compounds, such as methanol or glycols, in order to prevent hydrocarbon hydrate formation. The description of phase equilibria occurring in these conditions should be performed by equations of state associated with Helmholtz energies appropriate to strong demixings: SAFT and CPA equations were recently applied by Sun et al. [1] and Yan et al. [2] to oil reservoir fluids with water and methanol; in this work, the NRTL-PR cubic equation is considered for this purpose.

Due to the complexity of the oil fluid, both in terms of number of components and large amount of undefined compounds, lumping and delumping procedures associated are proposed for the NRTL-PR equation.

NRTL-PR modelling

The NRTL-PR equation (Non Random Two Liquids – Peng Robinson) previously developed for the modelling of hydrocarbons with water and glycols [3] is extended to mixtures containing pseudo-components. The attractive term a and the co-volume b of the EoS are expressed as follows:

GLK are the interaction energies between pseudo-components L and K, expressed from the interaction energies Γj(L)i(K) between components j and i, estimated from the group contribution method previously proposed [4]:


where: zint,i(K) is the mole fraction of component i in cut K and qi is the surface area parameter of component i.

Characterisation of oil fractions and lumping/delumping procedures

The above method should be associated with a molecular description of the oil fractions, so that the C7+ Pedersen method [5] based on a semi-continuous thermodynamics approach cannot be considered. In this work, the method initially proposed by Avaullée et al. [6] with the developed by Péneloux et al. [7] for non polar compounds, is extended to the NRTL-PR model.

The fluid is represented as follows: well defined light components, petroleum fractions from C4 to C19 (modelled with paraffins, naphtens and aromatics chosen according to the boiling point of the cut) and a C20+ heavy cut.

These fractions are usually modelled with the following pseudo-components: C4, C5-C10, C11-C19 and C20+. In this work we consider two lumping techniques, based either on the carbon atom numbers, Cn, or on the volatilities, Ki.

To improve the calculation of phase equilibrium compositions, a “dynamic” delumping method is proposed, which allows, once the phase equilibrium conditions between cuts K are satisfied, estimating new values of the internal mole fractions zint,i(K).

The proposed method is applied to the prediction of the bubble point pressures of several synthetic oil and gas and to the solubility of associating compounds in natural gases.

References [1] C.H. Sun, H. Zhao, C. Mc Cabe, AIChE (2007) 53, 720-731. [2] W. Yan, G.M. Kontogeorgis, S.H. Stenby, Fluid Phase Equilib. (2009) 276, 76-85. [3] E. Neau, J. Escandell, C. Nicolas, Ind. Eng. Chem. Res. (2010) 49, 7589-7596. [4] J. Escandell, E. Neau, C. Nicolas, Fluid Phase Equilib. (2011) 301, 80-97. [5] K.S. Pedersen, A.L. Blilie, K.K. Meisinyet, Ind. Eng. Chem. Res. (1992) 31, 1378-

1384. [6] L. Avaullée L., E. Neau E., J.-N. Jaubert, Fluid Phase Equilib.(1997) 139, 171-203. [7] A. Péneloux, W. Abdoul, E. Rauzy, Fluid Phase Equilib. (1989) 47, 115-132.


Detection of Solid-Liquid Retrograde Melting From Computing Solid-Fluid-Fluid Equilibrium Lines

Rodríguez Reartes S.B., Cismondi Duarte M., Zabaloy M.S.

Departamento de Ingeniería Química, Universidad Nacional del Sur – PLAPIQUI – CONICET, CC 717– 8000 – Bahía Blanca, Argentina

[email protected]

The occurrence of a temperature minimum, in the pressure-temperature (P-T) plane, for a solid-liquid phase boundary corresponding to a constant composition mixture (isopleth), is recognized as the phenomenon of solid-liquid retrograde melting [1]. According to Gregorowicz [1], the negative slope of the solid-liquid line emerging from the solid-fluid-fluid (SFF) equilibrium curve is the necessary condition for the retrograde phenomena to occur. Therefore, if a model for describing fluid-fluid and solid-fluid equilibria is available, and the model parameters are set equal to specific values, the possible occurrence of solid-liquid retrograde melting, within the universe of the model, should be established by computing the (P vs. T) slope of the solid-liquid isopleths emerging from the SFF curves given by the model. In this work, we propose an effective way for doing that, for the case of binary asymmetric systems. First, we compute, through a numerical continuation method (NCM), all the three-phase SFF equilibrium curves given by the model for a specific binary system. Next, for a given (already computed) three-phase SFF point, we use the information on the solid phase and on the liquid phase to obtain the Jacobian matrix corresponding to the system of equations that describes the two-phase solid-liquid isopleth with liquid composition equal to the liquid composition of the selected SFF point. From the Jacobian matrix, we compute a sensitivity vector. One of the components of such vector is the (P vs. T) slope of the two-phase solid-liquid isopleth at the point where the isopleth meets the three-phase SFF point. We repeat this procedure for all points of the computed SFF lines. The final result is a set of 2D plots which make possible to establish at a glance whether the model gives retrograde melting, at the specific parameter values previously set. When retrograde melting does exist for model, the 2D plots show the ranges of conditions of occurrence of such phenomena. We present results for SFF curves of varying shapes. Thanks to the use of a NCM, we can generate all the information required to build the 2D plots in a single run, for a given SFF curve. We also present in this work some calculated isopleths which we have obtained using an isopleth-specific NCM different from the SFF-specific NCM. For such calculated isopleths we show both, the stable and unstable parts. This makes possible to gain a deeper understanding of the retrograde melting phenomena. In the present exploratory work, we used the Peng-Robinson equation of state (EOS) for representing the properties of the fluid phases. Because of the highly asymmetric nature of the binary systems that we have considered in this work, the model assumes the solid phase as made of the pure heavy component. We used a standard equation for describing the fugacity of the pure heavy component, as a


function of temperature and pressure. The present model has proven to be realistic in our previous work related to the description solid-fluid equilibria over wide ranges of conditions.

References [1] J. Gregorowicz, Fluid Phase Equilib., (2006), 240, 29-39


Online cricondenbar monitoring in rich gas pipelines

Skouras E.1, Solbraa E.1, Christensen K.O.1, Løkken T.V.1, Aase B.Ø.1, Ovesen R.V.1, Aaserud C.2

1 - Statoil ASA 2 - Gassco AS

[email protected]

Introduction The knowledge of the hydrocarbon dew point is of great importance for the oil & gas industry as it is one of the gas quality specifications used for ensuring safe transport of natural gas. The most used dew point specification for natural gas transported in the European pipeline system, is the cricondentherm specification used for sales gas (SG). On the Norwegian continental shelf, rich gas pipelines are commonly used to transport partly processed gas from offshore installations to onshore processing facilities in the dense phase region at pressures higher than the cricondenbar.

Avoiding hydrocarbon condensation is crucial as the presence of liquids in the pipelines increases the pressure drop and introduces operational problems resulting from the two phase flow in pipelines designed for single phase transport. In addition, if condensation occurs, operational problems can arise in the inlet facilities of the onshore plants. Thus, knowledge of the hydrocarbon dew point temperatures and pressures of the gas, especially at the cricondenbar, is of great importance to obtain a safe and effective utilization of the rich gas pipelines and the onshore facilities.

Methodology The objective of the online cricondenbar monitoring project is to develop a method that enables an online analysis of the cricondenbar for rich gas pipelines. The method can be used to optimise production, control the delivered gas quality from rich gas producers and potentially to increase the pipeline throughput by decreasing the pipeline exit pressure.

The method for the online cricondenbar monitoring is illustrated in Fig. 1 and consists of:

An online gas chromatograph (GC) providing extended compositional analysis.

A reliable thermodynamic model for dew point predictions.


Figure 1. Components involved in the online cricondenbar monitoring method.

The thermodynamic model used is the UMR-PRU model, which is a recently developed EoS/GE model coupling the Peng-Robinson EoS with UNIFAC by utilizing the Universal Mixing Rule (UMR) [1-3]. In a recent study, the UMR-PRU model has been succesfully applied to the prediction of the dew points of synthetic and real natural gases [4, 5].

The GC used for the online gas analysis is a Siemens Maxum II process GC. For reliable hydrocarbon dew point calculations, an extended gas analysis is required. The GC application used can identify all hydrocarbon components up to C6 together with N2 and CO2. For the C7+ fraction, all n-alkanes up to C10 are identified together with aromatic components such as benzene, toluene and xylenes and napthenic components such as methylcyclopentane, cyclohexane, methyl-cyclohexane and ethylcyclopentane. Finally, in each carbon fraction, some unknown components are identified, which are treated as 1/3 parafinns (P), 1/3 napthenics (N) and 1/3 aromatics (A), according to the PNA characterisation method described by Rusten et al. [6].

References [1] E. Voutsas, K. Magoulas and D. Tassios, Ind. Eng. Chem. Res., (2004), 43, 6238-6246. [2] E. Voutsas, V. Louli, C. Boukouvalas, K. Magoulas and D. Tassios, Fluid Phase Equil., (2006), 241, 216-228. [3] V. Louli, C. Boukouvalas, E. Voutsas, K. Magoulas and D. Tassios, Fluid Phase Equil., (2007), 261, 351-358. [4] E. Skouras, E. Voutsas, V. Louli, E. Solbraa, Proceedings ESAT 2009, 206, Santiago de Compostela, Spain. [5] E. Skouras, V. Louli, G. Pappa, C. Boukouvalas, E. Solbraa, E. Voutsas, Proceedings CHISA 2010 (Summaries 2), 336, Prague, Czech Republic. [6] B. H. Rusten, L. H. Gjertsen, E. Solbraa, T. Kirkerød, T. Haugum and S. Puntervold, GPA Annual Conference, (2008), Texas.

Online Gas Chromatographic analysis and Component Grouping

Thermodynamic model for calculation of dew points

Calculation of dew points

Online CricondenbarMonitoring


Distribution of gas hydrate inhibitors in oil and gas production systems

Riaz M.1, Kontogeorgis G.M.1, Stenby E.H.2, Yan W.2, Haugum T.3, Christensen K.O.3, Solbraa E.3, Løkken T.V.3

1 - Department of Chemical and Biochemical Engineering, Center for Energy Resources Engineering (CERE), Technical University of Denmark, DK-2800 Lyngby, Denmark

2 - Department of Chemistry, Center for Energy Resources Engineering (CERE),Technical University of Denmark, DK-2800 Lyngby, Denmark

3 - Statoil ASA, Research and Development Center, N-7005 Trondheim, Norway

[email protected]

Chemicals are added in almost all the stages in oil and gas production. It is generally accepted that efficient and cost effective oil and gas production is not possible without the use of chemicals. Monoethylene glycol (MEG) and methanol are two of the most widely used production chemicals. They are used as gas hydrate inhibitors to ensure safe production and transportation. This work presents new experimental phase equilibrium data for “MEG + reservoir fluid” and “MEG + reservoir fluid + water” systems at temperatures 275-323 K and at atmospheric pressure. Reservoir fluid consists of a natural gas condensate from a gas field in the North Sea with composition (in mole percent) 0.014% i-C4, 0.491% n-C4, 9.49% i-C5, 11.32% n-C5, 13.29% C6, 19.37% C7, 17.10% C8, 7.78% C9 and 21.16% C10+. The prediction of mutual solubility of water, MEG and hydrocarbon fluids is important for oil industry to insure production and processing as well as to satisfy environmental regulations. The CPA equation of state proposed by Kontogeorgis et al. [1] has been successfully applied in the past to well defined systems containing associating compounds. It has also been extended to reservoir fluids in presence of water and polar chemicals using a Pedersen et al. [2] like method of characterization, with modified correlations for critical temperature, critical pressure and acentric factor, proposed by Yan et al. [3]. In this work CPA is applied for the prediction of mutual solubility of hydrocarbon fluid and polar compounds such as water and MEG. Satisfactory modeling results are obtained for mutual solubility of MEG and condensate as well as for the MEG + water + condensate mixtures considering that a single and same temperature independent binary interaction parameter is used for all MEG-hydrocarbon mixtures. Furthermore, the distribution of MEG and methanol in hydrocarbon liquid and vapor phase is also modeled. References [1] G. M. Kontogeorgis, E. C. Voutsas, I. V. Yakoumis, D. P. Tassios, Ind. Eng. Chem. Res. 35 (1996) 4310. [2] K. S. Pedersen, P. Thomassen, A. Fredenslund, Characterization of gas condensate mixtures, Advances in thermodynamics, Taylor & Francis, New York, 1989. [3] W. Yan, G. M. Kontogeorgis, E. H. Stenby, Fluid Phase Equilib., 276 (2009) 75-85.


Towards a group-contribution method to predict temperature-dependent binary interaction parameters (kij)

whatever the cubic equation of state and the associated alpha function

Jaubert J.-N., Privat R.

Nancy-Université, Ecole Nationale Supérieure des Industries Chimiques, Laboratoire Réactions et Génie des Procédés, 1 rue Grandville, B.P. 20451, F-54001 Nancy Cedex

[email protected]

Chemical engineers from petroleum companies widely use cubic equations of state (EoS) and especially the ones proposed by Peng and Robinson (Peng-Robinson EoS noted PR EoS afterwards) and by Soave (Soave-Redlich-Kwong EoS, noted SRK EoS afterwards). The key point when using such EoS to describe complex mixtures is to give appropriate values to the binary interaction parameters (BIPs). We however know by experience that the BIPs, suitable for a given EoS (e.g. the PR-EoS) cannot be directly used for another one (e.g. the SRK EoS). Moreover, numerical values of BIPs are not only specific to the considered EoS but they also depend on the alpha-function (Soave, Twu, Mathias-Copeman, etc.) involved in the mathematical expression of the ai parameter. This assessment makes it impossible for petroleum engineers to use various equations of state and to test different alpha functions. Indeed, they usually have tables containing the numerical values of the BIPs only for the most widely used EoS and alpha function in their company.

To overcome this limitation, our idea was to establish a relationship between the BIPs of a first EoS ( EoS1

ijk ) and those of a second one ( EoS2ijk ). As a consequence, knowing the

numerical values of the BIPs for the first EoS makes it possible to deduce the corresponding values for any other cubic EoS. This objective could be reached thanks to the rigorous equivalence between the classical mixing rules with temperature-dependent kij and the combination at constant packing fraction of a Van Laar-type excess Gibbs energy model with a cubic EoS. Our key idea was to make the hypothesis that the infinite pressure residual molar excess Gibbs energy ( E,

resg ∞ ) was independent of the used EoS. The obtained relationship is given just below (Eq. 1). To understand the notations, let us consider two cubic equations of state (EoS1 and EoS2) deriving from the Van der Waals equation i.e. taking the general following form:


( ) ( )( )i

i 1 i 2 i

a (T)RTP T, vv b v r b v r b

= −− − −

with

c,ii b

c,i2 2

c,ii a i c,i i

c,i

RTb

P

R Ta (T) (T,T , )

P

= Ω

= Ω ⋅α ω

where parameters 1r and 2r are specific to each equation. At this step, we define the following quantities:

1 2EoS 1 2 EoS 1 1 2

2

1EoS1

EoS1 b1 2 EoS2

EoS2 b

EoSiEoS

i EoSi

r rC if r r C 1 r if r r1 rln1 r

CC

ab

and

→

− = ≠ = − = − − ⋅Ωξ = ⋅Ω

δ =

After some derivation, the obtained relationship is:

( ) ( )2 2E oS1 E oS1 E oS1 E oS1 E oS1 E oS 2 E oS 21 2 ij i j 1 2 i j i jE oS 2

ij E oS 2 E oS 2i j

2 kk

2→ →ξ δ δ + ξ δ − δ − δ − δ

=δ δ

(1)

Moreover, since 2004, we develop the PPR78 model which is a group contribution method (GCM) for the estimation of the temperature-dependent BIPs of the PR EoS. Using Eq. (1), this GCM can be used to generate the kij for any desired cubic EoS, with any desired ai(T) function. The coupling of the PPR78 model and Eq. (1) makes it unnecessary to re-estimate the group-contribution parameters for the desired EoS. A very long, tedious and difficult job can thus been saved. The most important conclusion is that the results obtained with this approach are in many cases very accurate in both the sub-critical and critical regions. We can thus conclude that the hypothesis we made ( E,

resg ∞ independent of the EoS) is pertinent. As a consequence, we are able to estimate by GC the temperature-dependent kij of any desired cubic EoS with any desired alpha function.


Gas mixtures solubility in polyethylene below its melting temperature. A molecular simulation study

Rousseau B.1, Lachet V.2, Memari P.1,2

1 - Laboratoire de Chimie Physique, Université Paris-Sud 11, UMR 8000 CNRS, Orsay, France 2 - IFP Energies nouvelles, 1 & 4 av. de Bois-Préau, Rueil-Malmaison, France

[email protected]

Introduction The accurate knowledge of the transport properties of gases in polymeric materials is crucial for technological applications, since these properties govern the behavior of end products under specific use condition. One example concerns flexible pipes used as flowlines and risers for offshore oil and gas production. A typical pipe structure is made of several different layers whose main components are thermoplastics acting as a barrier, high strength carbon steel wires and a corrosion resistant carcass. The main function of polymer sheaths is to ensure pipe leak proof to both external environment and conveyed fluids. In offshore oil and gas production, materials might be in contact with water, hydrocarbons, gases and all carried fluids at high temperature and high pressure. Another interesting example is the case of plastic pipes used for gas distribution network. In the context of new energies, hydrogen is taking a growing place and its introduction in existing distribution pipes as a mixture with natural gas can be an alternative to its transport. Owing to safety and economic reasons, one of the main questions concerns the possible leakage of hydrogen by permeation through the pipe, either pure or mixed with light hydrocarbons.

In this work, we will present solubility results for two gas mixtures in polyethylene, methane-carbon dioxide and methane-hydrogen, obtained using molecular simulation.

Methodology Molecular simulation is an attractive tool to calculate solubility as it relies on methods with few assumptions and is based on well-defined molecular characteristics. We will put emphasis here on the computation of solubility of penetrant mixtures into a semicrystalline polymer. Indeed, in most of the simulation work previously published, solubility has been obtained either in melt or purely amorphous polymer, or, in the case of semicrystalline materials, within the assumption that the amorphous phase is the only permeable phase and that the amorphous phase characteristics are not affected by the presence of the crystalline regions. We recently demonstrated that experimental solubility of many different pure gases can be recovered using Monte Carlo simulations in the osmotic ensemble, both in the melt phase [1] and in the semicrystalline phase [2]. In the latter case, an original use of the osmotic ensemble has been introduced that


allows an implicit account of the complex morphology of semicrystalline materials. We will apply this methodology to the study of mixtures.

Results In this work, we will focus on the solubility of CH4-CO2 and CH4-H2 mixtures in polyethylene, at (almost) ambient temperature and pressure below 3 MPa. Simulation results will be compared with available experimental data. We will investigate the solubility selectivity and we will check for the presence of coupling effects or competition between gases that may occur and would affect permeability behaviour.

References [1] F. Faure, B. Rousseau, V. Lachet, P. Ungerer, Molecular simulation of the solubility and diffusion of carbon dioxide and hydrogensulfide in polyethylene melts, Fluid Phase Equilibria. 261 (2007) 168-175. [2] P. Memari, V. Lachet, B. Rousseau, Molecular simulations of the solubility of gases in polyethylene below its melting temperature, Polymer. 51 (2010) 4978-4984.


Phase Stability Analysis Using a Reduction Method

Nichita D.V.

CNRS UMR 5150, Laboratoire des Fluides Complexes, University of Pau et des Pays de l’Adour, Pau, France

[email protected]

The most important computational effort in many process simulators and in petroleum reservoir compositional simulations is required by phase equilibrium and thermodynamic properties calculations. Phase stability testing is an important subproblem in phase equilibrium calculations; it consists in finding either all stationary points or only the global minimum of the Gibbs tangent plane distance (TPD) function [1], and it its results are of high importance for initialization of multiphase flash calculations. The TPD surface is non-convex and may be highly nonlinear, and many phase stability calculations are rather difficult. Besides, compositions of many effluents in chemical and petroleum engineering are characterized by a (very) large number of components, resulting in time-consuming simulations.

In order to reduce the computer time, a very attractive alternative to the widely used technique of lumping into pseudo-components is given by the so-called reduction methods. In any reduction method the dimensionality of the phase equilibrium problem can be significantly reduced, and the number of independent variables does not depend on the number of components in the mixture, but only on the number of non-zero binary interaction parameters (BIPs) in the equation of state (EoS), thus the use of a detailed fluid composition is allowed. The reduction methods are particularly efficient for mixtures with many components and few non-zero BIPs (such as naturally occurring hydrocarbon systems). In terms of stability analysis, the use of reduction methods [2] is extremely attractive since the TPD surface is smoother in the reduced spaced than in the compositional space [3,4].

In this work, a recently proposed [5] set of independent variables (and the suitable related set of error equations) is used, based on the observation that the equilibrium ratios (or fugacity coefficients) can be related only to some component properties (elements of the reduction matrix, as defined in Hendriks’ Reduction Theorem [6]) and to the equation of state parameters. A general form of two-parameter cubic equation of state is used in this work, but it should be noticed that the applicability of the method is restricted by the mixing rules and not by the form of the equation of state. The reduction is effectively achieved by spectral decomposition of the BIP matrix. The proposed iterative solution consists in quasi-Newton iterations (with simpler expressions of the elements of the gradient vectors), followed by second-order Newton iterations (with simpler expressions of the elements of the Jacobian matrix). In most cases, the convergence is obtained using only few full Newton iterations.


The reliability and efficiency of the proposed method are tested on a variety of hydrocarbon synthetic and reservoir mixtures with various phase envelope shapes, with emphasis to calculations near the phase boundaries and in the immediate vicinity of singularities (critical points and the stability test limit locus, whose vicinity contains the most severe conditions for any stability testing algorithm [7,8]). Comparison with conventional methods (in the compositional space) and other reduction methods recommend the proposed method for stability testing of mixtures with many components in process and reservoir simulators.

References [1] M.L. Michelsen, Fluid Phase Equilib. (1982),9, 1-20. [2] D.V. Nichita, D. Broseta and J.-C.de Hemptinne, Fluid Phase Equilibria (2006), 246, 15-27. [3] A. Firoozabadi and H. Pan, Soc. Petrol. Eng. J. (2002),7, 78-89. [4] D.V. Nichita, S. Gomez and E. Luna, Fluid Phase Equilibria (2002), 194-197, 411-437. [5] D.V. Nichita and A. Graciaa, paper in press, Fluid Phase Equilibria, 2011. doi: 10.1016/j.fluid.2010.11.007 [6] E. Hendriks, Ind. Eng. Chem. Res. (1988), 27, 1728-1732. [7] H. Hoteit and A. Firoozabadi. AIChE J. (2006), 52, 2909-2920. [8] D.V. Nichita, D.Broseta and F. Montel, Fluid Phase Equilibria, 261 (1-2), 176-184, 2007.


Sunday, 26.06.2011

PLENARY SESSION


The Universal Group Contribution Equation of State VTPR - Present Status and Potential for Process Development

Gmehling J., Schmid B.

University of Oldenburg, Germany

[email protected]

For the development of unit operations or whole plants in the chemical, pharmaceutical, gas processing, petrochemical, food and environmental industry reliable predictive models with a large range of applicability are required.

Group contribution equations of state in comparison to UNIFAC or modified UNIFAC show different advantages. They can be applied to systems with supercritical compounds. At the same time other important properties such as enthalpies, heat capacities, densities (e.g. excess volumes), entropies, etc. for the pure compounds and their mixtures are obtained as a function of temperature, pressure and composition. Therefore e.g. the group contribution equation of state PSRK was implemented in different process simulators.

To eliminate the still existing weaknesses of PSRK, another group contribution equation of state with improved mixing rules and temperature-dependent parameters was developed. For fitting the temperature-dependent group interaction parameters all kind of phase equilibrium data (VLE, activity coefficients at infinite dilution, LLE, SLE of eutectic systems, gas solubilities, azeotropic data) and excess properties (excess enthalpies, excess heat capacities) stored in the Dortmund Data Bank are used.

The result of these activities is the universal group contribution equation of state VTPR. In the lecture the improved results of the group contribution equation of state VTPR for pure component properties, phase equilibria, excess properties and typical applications for process development will be presented.


Fundamental Equation of State for Solid Phase I of Carbon Dioxide

Trusler J.P.M.

Imperial College London

[email protected]

Introduction Solid carbon dioxide is of importance in a number of scientific and engineering contexts including cryogenic gas processing, safety and flow assurance in pipeline systems for the transmission of CO2, and in planetary science. Although wide-ranging equations of state are available for the fluid phases of CO2, a fundamental equation of state is not presently available for the solid, and the objective of the present work was to provide such an equation.

Available Experimental Data Solid carbon dioxide is known to exist in a number of polymorphs with the cubic phase I being the stable form at pressures below about 11 GPa at ambient temperature. A considerable body of experimental data is available. The sublimation curve has been measured from low temperatures to the triple point, and the melting curve has been measured from the triple point up to approximately 800 K. The molar volume of the solid has been measured by means of x-ray diffraction both at low pressures, along the sublimation curve, and at pressures up to 12 GPa and temperatures up to 800 K in diamond anvil cells. The thermal expansion coefficient, longitudinal and transverse speeds of sound and the isobaric molar heat capacity have all been measured along the sublimation curve from very low temperatures up to the normal sublimation temperature. The isentropic bulk modulus has also been measured at T = 300 K at pressures up to 6 GPa.

The infra-red and Raman active lattice modes of solid CO2 have been extensively studied, and inelastic neutron scattering has been used to obtain phonon dispersion curves for all 20 optical and acoustic lattice modes of the crystal.

Model Construction The model was initially constructed in two parts. The first was an empirical equation for the molar volume based on expressions for the molar volume of the hypothetical solid at zero pressure and an expression for the relative volume under compression. This was fitted to the available data for molar volume, thermal expansivity and isothermal bulk modulus. The second component was a model for the molar heat capacity at constant volume of the crystal along the isochore originating at zero temperature and zero pressure. This was based on a combined Debye-Einstein model for the contributions of the various lattice modes of solid CO2. In order to test and fine tune the heat-capacity


model, the predicted isochoric heat capacity of the solid on the sublimation curve was computed and compared with that obtained from purely experimental data.

Having established functional representations of the pVT and caloric properties in this way, a combined Gibbs free energy function was constructed and the parameters optimised in a simultaneous fit to all the available experimental data. The resulting model is valid for essentially the entire range of stability of phase I with pressures up to 12 GPa and temperatures up to 800 K. It fits the molar volume in this wide range with an absolute average relative deviation of 1%. The heat capacity, thermal expansivity and isothermal bulk modulus are represented to almost within experimental uncertainties along the entire sublimation curve, and the phase boundaries are also predicted accurately.


Monday, 27.06.2011

PLENARY SESSION


Predictive approach for aqueous amine acid gas loading

Schrey A.1, Westerholt A.2, Fischer K.2, Hendriks E.2

1 - Thermal Process Engineering, RWTH Aachen, Am Ehrenfriedhof 7, 51379 Leverkusen, Germany

2 - Shell Technology Centre Amsterdam, Grasweg 31, 1031 HW Amsterdam, The Netherlands

[email protected]

Aqueous alkanolamine solutions are employed for the removal of contaminants such as hydrogen sulfide and carbon dioxide from pre- and post-combustion gas. The basic set up is two columns: an absorber operating at pressures up to 100 bar and temperatures between 20°C and 40°C, and a regenerator operating at pressures below 10 bar and temperatures between 80°C and 120°C. Thermodynamic modeling of this weak electrolyte system is challenging, as the process involves the interplay of physical dissolution, chemical reactions and electrolytes, occurring in a mixed aqueous solvent, as often special components such as sulfolane are added to enhance capacity and/or selectivity. The pressure range spans various orders of magnitude. A number of approaches have been developed, which differ in the type or number of reactions taken into account, the non-idealities in especially the liquid phase using for example Henry’s law, (electrolyte) activity coefficient model or (electrolyte) equations of state [1]. For a recent overview see [1] and references therein.

Existing models usually contain many parameters, typically around thirty per amine, which can be strongly inter-correlated with respect to the experimental data. For example, at very low partial pressures of the contaminant, the loading depends on the product of chemical equilibrium constant and Henry constant, not on each of them separately. Having a large number of parameters adds flexibility, but this does not imply higher accuracy when properties are derived from interpolation or extrapolation of measured data. It is also striking that in some approaches, many reactions are taken into account but physical non-idealities are ignored, whilst in others it is the reverse.

As an alternate approach, we are developing a very simple model taking into account only the primary absorption effects, but enough of them to represent data over the entire relevant range of conditions and compositions. We consider the main net chemical reactions of solvent and solute and apply the Henry approach to describe physical absorption of solute in the liquid. Secondary effects such as the formation of ions are not considered, as the accuracy of experimental data often does not allow quantifying them. Also temperature dependencies of the single model parameters are described with relatively few parameters. With this pragmatic perspective the systems can be modeled with a relatively lower number of experimental data points. The model parameters can be determined with higher confidence, also for amines for which experimental data are scarce. The goal is to obtain a single model valid over a broad range of solute partial pressures, temperature, and solvent water content which can still sufficiently describe

Invited Lecture


the solute loading of aqueous amine solvents having a good capability for interpolation and extrapolation. The average deviations in loading found are typically around 10% for tertiary amines and 15% for secondary and primary amines.

We also derive a correlation of the model parameters with the molecular structure of the amines. An average model deviation on the carbon dioxide loading for nine different pure amines of less than 20% was achieved. With this model in principle parameters can be estimated for amines which have not been experimentally investigated.

Experimental data from a large number of different sources were included in this study. The model can thus be tested against data from many different authors avoiding a bias due to selection of specific experimental data sets. Only experimental data strongly contradicting the general trend has been excluded.

References [1] G. Kontogeorgis and G. Folas. Thermodynamic Models for Industrial Applications: From Classical and Advanced Mixing Rules to Association Theories. Wiley, 2010.


Phase equilibrium in natural gas mixtures

Voutsas E.

School of Chemical Engineering, National Technical University of Athens, GREECE

[email protected]

Phase behavior of natural gases at pressures well above atmospheric pressure is of great interest for the oil and gas industry, since they provide important information on the design of recovery and processing operations of natural gases at high pressures. The phase envelope has numerous applications in oil and gas production and process design ranging from reservoir simulation, transportation of natural gas by pipeline or in liquefied natural gas (LNG) form, ethane plus recovery, compression and refrigeration processes, and operation near the critical point or in the supercritical region. In short, reliable process design requires the accurate knowledge of the hydrocarbon phase envelope.

The dew point curve is particularly relevant to the production and transport of hydrocarbon mixtures. Natural gas dew point is crucial in determining if the gas can be transported safely through national and international pipeline networks. Maximum legislative levels for hydrocarbon dew point are set in order to prevent the formation of liquid condensate in the pipeline, which could have severe consequences for the safe transportation of natural gas. Furthermore, accurate natural gas phase equilibrium predictions will assist in controlling gas processing. Good processing will prevent shut-ins, helps maintaining pipeline integrity and prevents –at the same time- hydrate formation which could damage in-stream devices such as compressors, valves, sample probes and orifice plates.

Cubic equations of state (CEoS), such as the Peng-Robinson or Soave-Redlich-Kwong, matched with the classical van der Waals one-fluid mixing rules, are routinely used by the oil and gas industry for the design of recovery and processing operations of natural gases. Previous studies have pointed out that CEoS have difficulty in representing correctly the whole phase envelope with both the cricondentherm and the cricondenbar, which are the saturation points with largest pressure and temperature at which the fluid can be in the two-phase region, respectively.

The presentation will cover some important issues and needs of the oil and gas industry with respect to the phase equilibrium of natural gas mixtures. Illustrative issues are the prediction of the dew point curve and, especially, the cricondenbar and the cricondentherm using traditional CEoS, EoS/GE models and non-cubic EoS derived from statistical thermodynamics, the prediction of the vapor-liquid critical point, the characterization of the heavy fraction whose complete compositional analysis is not available and is an important step in the application of equations of state for phase equilibrium calculations, etc.

Invited Lecture


Restricted Dynamics of Hydrocarbon Chain in Lamellar Phase of Lipid-Water Systems

Saito K., Yamamura Y.

Department of Chemistry, Graduate School of Pure and Applied Sciences,University of Tsukuba, Tsukuba, Ibaraki 305-8571, JAPAN

[email protected]

Dynamics of hydrocarbon chains are believed to play a crucial role in the emergence of property/functionality of biological membranes. As a contribution from thermodynamic community, the calorimetric study was started on lamellar (Lα) phases in three lyotropic systems consisting of water and lipids, molecules of which have the chain with the same length (the same number of carbon atoms) but different shapes in isolated equilibrium. The difference concerns with the trans/cis isomerism and/or the position of a C=C double bond in the chain.

Heat capacities were measured by adiabatic calorimetry. The measured heat capacities of monoolein/water and monoelaidin/water systems are shown in Fig. 1. Anomalies due to the lamellar to isotropic phase transition are clearly seen. The entropy of transition (∆trsS) for each system was estimated from the area of the anomaly. The ∆trsS of monoolein/water and monovaccenin/water are ca. 0.8-0.9 J K-1 (mol of lipid)-1 whereas that of monoelaidin/water ca. 0.4 J K-1 (mol of lipid)-1. For the isotropic phase, it is reasonable to assume that the chains are sufficiently disordered. Since the chains of all lipids under consideration have the same number of conformations because of their chemical structure, the entropy in the isotropic phase is essentially the same. The difference in ∆trsS should therefore be attributed to the difference in the number of available conformations of the chain in the lamellar phases, where molecules have, in average, cylindrical forms (packing parameter ≈ 1). The experimental ∆trsS indicate that the dynamics of the chain of monoolein and monovaccenin (cis-form) are more restricted than that of monoelaidin (trans-form) in the lamellar phase. The difference between monoolein and monovaccenin systems is subtle but can be related to the difference in the position of a C=C bond.

Figure 1. Heat capacities of lipid/water systems.

Invited Lecture


Van der Waals and Beyond

Peters C.J.1,2,3

1 - University of Maryland, Department of Chemical and Bio-molecular Engineering , College Park, MD 20742, USA College Park, MD 20742, USA

2 - Delft University of Technology, Faculty of Mechanical, Maritime and Materials Engineering, Department of Processes and Energy, Leeghwaterstraat 44, 2628 CA Delft, The Netherlands 3 - Petroleum Institute, Department of Chemical Engineering, Petroleum Institute, P.O. Box

2533, Abu Dhabi, United Arab Emirates

[email protected]

On December 10th 2010, it was 100 years ago since Johannes Diderik van der Waals received in Stockholm the Nobel Prize for Physics for his breakthrough work on the equation of state of gases and liquids. This event is reason enough to commemorate this historic event at the 25th European Symposium on Applied Thermodynamics. In van der Waals’ doctoral thesis of 1873, for the first time a theory of gases and liquids, based on differences in molecules and their interactions, was proposed, allowing to understand at what conditions gases could be liquefied. The concept of continuity of gases and liquids still comprises the

basis of all equations of state that plays such an important role in the prediction of phase behavior and other thermodynamic properties of fluid phase systems in all kinds of practical applications. The importance of van der Waals’ concept is reflected in the countless number of articles that still refer to this basic knowledge.

Besides van der Waals’ major contribution on the understanding of how gases and liquids transform into each other, including critical behavior, he was the first who extended this work to binary and ternary mixtures. Also the introduction of the corresponding states principle originates from the work of van der Waals. In addition, pioneering work in the field of capillarity, molecular interactions, theory of solutions and, last but not least, the square gradient theory of inhomogeneous fluids (many decades later rediscovered by Cahn and Hilliard) provided a wealth of basic thermodynamic knowledge.

The basic concepts of van der Waals are still recognizable in many modern studies and applications, varying from industrial process simulators to molecular simulations.


Mendeleev density studies of Ethanol + Water Mixtures. What have we learnt about the treatment of experimental results

since then?

Lampreia I.M.S., Lourenço M.J.V., Nieto De Castro C.A.

Departamento de Química e Bioquímica and Centro de Ciências Moleculares e Materiais, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal

[email protected]

On February 8, 2009 it is 175 years since the birthday of Dmitrii Ivanovich Mendeleev, the author of the Periodic Law and Periodic System of Chemical Elements. Besides this discovery, the outstanding Russian Scientist, Dmitrii I. Mendeleev, gave important contributions in the field of Metrology. In 1865 he received his PhD from the University of St. Petersburg for his Doctoral thesis ‘On the Compounds of Alcohol and Water’. His concern about obtaining precise measurements of fundamental quantities, such as pressure and density, lead him to construct his own instruments (Mendeleev pycnometer in the field of density) [1-3]. His experimental determination of density values for pure liquids, such as water and mercury, and mixtures of ethanol + water, was one of the most important contributions mainly in the domain of critical analysis and mathematical treatment of the data.

Figure 1. The pycnometer used by Mendeleev for the measurement of the density of ethanol + water mixtures [1] In this work we compare his data for aqueous mixtures of ethanol with those obtained by well reputed scientists of our time [4,5]. We further compare the information


obtained by his brilliant concern about the dependence on composition of the density derivative with respect to composition with the present methods, mainly based on partial molar quantities. We show that the most relevant information that we can now obtain by elaborated methods of fitting data [6,7] were already been obtained by Mendeleev, at that time, when he observed sharp breaks at definite molar proportions of the two components in the density derivative dependence described above.

We have applied his method to other amphiphilic + water mixtures and observed identical results as illustrated before.

References [1] N. A. Gaevskii, E. F. Dokinskii, Izmeritel'naya Tekhnika, No. 9, (1969) 28-31. [2] I. S. Dmitriev, P. D. Sarkisov, I. I. Moiseev, Rend. Fis. Acc. Lincei 21 (2010) 111–130 [3] D. I. Mendeleev, Works, Vol. 4, ONTI-Khimteoret, 1937. [4] K. N. Marsh, A. E. Richards, Aust. J. Chem. 33 (1980) 2121–2132. [5] G. C. Benson, O. Kiyohara, J. Solution Chem., 9 (1980) 791–804. [6] M. I. Davis, G. Douhéret, Thermochim. Acta 188 (1991) 229-247. [7] A. F. S. Santos, M. L. C. J. Moita, I. M. S. Lampreia, J. Chem. Thermodyn. 41 (2009) 1387-1393.


Thermodynamic properties of ionic liquids and their mixtures

Heintz A.

University of Rostock

[email protected]

Since for more than 10 years ionic liquids (IL) have gained a dramatically increasing importance in many branches of chemistry and chemical engineering. The basis of most applications is a fundamental understanding of the relationship between macroscopic properties and molecular structure. A great deal of thermodynamic data has been collected and systematically evaluated during the last few years not only on pure ILs but also on their mixtures with other solvents. In this lecture both aspects, those of pure ILs and their mixtures will be presented.

The most remarkable property of ILs is their very low, almost not detectable vapour pressure. It will be shown, how recently developed techniques and equipment enables us to measure vapour pressure of ILs and, even more important, heats of vaporisation. This has been achieved by using combinations of vapour transpiration techniques, Knudsen effusion technique, high precision combustion calorimetry, adiabatic calorimetry for measuring heat capacities and quantum mechanical ab initio calculations. Several methods will be discussed. A series of standard formation enthalpies of ILs in the gaseous phase will also be presented and the consistency of the results obtained by different methods will be discussed.

IL + solvent mixtures are of particular interest in chemical engineering process such as extraction and separation of valuable chemical products. New LLE, VLE data and activity coefficients including values in high dilution of the solvent in ILs as well as ILs in solvents will be presented and discussed. Most recently surface excess concentration have been obtained by simultaneous measurements of bulk activity coefficients and surface tension of IL + solvent mixture revealing interesting aspects of the surface structure of such mixtures ranging from a typically behaviour expected from electrolyte solutions to surfactant like properties including micellation processes. Viscosity and diffusion are transport properties of great interest for testing molecular dynamic computer results and the force fields of the IL cations and anions on which the results are based. Some examples of such a comparison will also be presented.

Invited Lecture


Use of high pressure flow calorimetry in the evaluation of the CO2 capture and sequestration technologies

Le Parlouër P., Etherington G.

Setaram Instrumentation, 7 Rue de l'Oratoire, 69300 Caluire, France

[email protected]

CO2 capture technologies have long been used by industry to remove CO2 from gas streams where it is not wanted or to separate CO2 as a product gas. There are currently three primary methods for CO2 capture: post-combustion, pre-combustion and oxy-fuel.

Post-combustion involves scrubbing the CO2 out of flue gases from combustion process, through the use of chemical sorbents. This is today one of the most popular absorption technique for the CO2 capture in post combustion processes. In such an industrial process, the amine solution is introduced at the top of an absorption tower while the exhausted fume containing carbon dioxide is introduced at the bottom. As an intimate contact is reached in the absorption tower, the amine solution chemically absorbs the carbon dioxide from the gaseous stream. Such a process especially requires two types of thermodynamic parameters: gas solubility and enthalpy of adsorption. The enthalpy of absorption, according to the amount of absorbed gas and the corresponding heat capacities of solutions, define the temperatures of the fluids when they exit the adsorption columns.

Flow mixing calorimetry is the ideal technique for measuring such enthalpies of adsorption. In order to work under pressure, a dedicated high pressure mixing vessel is adapted to be used on the Setaram C80 calorimeter. The mixing vessel is made of a stainless steel tube in a helicoidal shape into a cylindrical container. The length of the tube in closed thermal contact with the cylinder is about 240 cm. The fluids (CO2 and amine solution) are introduced at the bottom part of the vessel in two vertical and concentrical tubes. The mixing (dissolution, reaction) starts when the thinner part of the tube is reached. The heat that is associated with the reaction, is exchanged between the rolled tube and the calorimetric block through the wall of the vessel in a isothermal mode. The flow mixing vessel operates from room temperature to 200°C and for a range of fluid pressure from 0.1 to 20 MPa. The fluid flowrates vary from 50 to 1500 µl.min−1, that allow to cover a wide range of mixture composition.

CO2 sequestration involves the injection of CO2 into a geologic formation to enhance carbon recovery. The three options for geological CO2 storage are saline formations, oil and gas reservoirs, and deep unminable coal seams. Among the storage possibilities, the injection of CO2 in large amounts of natural methane hydrate that exists in ocean sediments is one investigated option. In that case the formation of CO2 hydrates is expected with a dissociation of the methane hydrates. High pressure calorimetry has proved to be a very interesting technique in the investigation of formation and


dissociation of gas hydrates under high pressure conditions and is applied to the investigation of CO2 hydrates.

Figure 1. The high pressure flow mixing vessel for the study of CO2 capture in amine solutions



POSTER SESSION 1


PI-1. Parameter estimation for the PCP-SAFT EOS using a minimal amount of experimental data

Albers K.1, Heilig M.2, Sadowski G.1

1 - Department of Biochemical and Chemical Engineering, Laboratory of Thermodynamics, TU Dortmund, Emil-Figge-Str. 70, 44227 Dortmund, GERMANY

2 - BASF SE, 67056 Ludwigshafen, GERMANY

[email protected]

The Perturbed Chain Polar-Statistical Associating Fluid Theory (PCP-SAFT)1-3 is a commonly used equation of state for modeling the thermodynamic behavior of pure fluids or mixtures. The model requires three pure-component parameters for non-associating and five parameters for associating components. These pure-component parameters are usually fitted to experimental vapor-pressure and liquid-density data in broad temperature ranges. However, experimental data are often rare or even lacking. Therefore, the aim of this work was to develop an optimized strategy for estimating the pure-component parameters based on a minimal amount of experimental data.

Analysis revealed that for all considered substances parameter fitting is possible and reliable with only as many data points as parameters to be fitted. Moreover, these points are not obliged to cover broad temperature ranges. The reliable fit could be obtained by using only two vapor-pressures (at temperatures that differ only by 5 K) and one liquid density for non associating components. For the associating components three vapor-pressures (in a temperature interval of 20 K) and two liquid densities (at temperatures differing by 5 K) were required.

The subsequent investigation of parameter correlations within different homologous series showed that the parameters segment number, segment diameter and dispersion-energy correlate linearly with molar mass-related quantities. Within this investigation the homologous series of n-alkanes, 1-alkenes, 1-alkynes, n-alkyl benzenes, 2.2-dimethyl n-alkanes, 2-ketones, di-n-alkyl ethers and n-alkyl acetates were considered. In case of associating components, such as 1-alkanols and n-alkylthiols, the association volume was fixed to a certain value specific for a homologous series. Doing this, the association-energy parameter correlates very well with the quantum-mechanically derived associative contribution to the enthalpy of vaporization given by COSMO–RS4.

Application of the so-obtained parameter sets to the modeling of pure components and binary mixtures leads to reliable results. These can be improved by fitting the dispersion-energy parameter to one experimental data point, e.g. the normal boiling point. This reduces the amount of required experimental data for pure-component parameter estimation to only one data point at maximum.


References [1] J. Gross and G. Sadowski, Ind. Eng. Chem. Res., (2001), 40, 1244-1260. [2] J. Gross and G. Sadowski, Ind. Eng. Chem. Res., (2002), 41, 5510-5515. [3] J. Gross and J. Vrabec, AIChE Journal, (2006), 52, 1194-1204. [4] A. Klamt, J. Phys. Chem., (1995), 99, 2224-2235.


PI-2. Including polarizability effects in GC-PPC-SAFT: application to alkyl-ether containing systems

Auger E.1, Passarello J.P.1, Paricaud P.2, Tobaly P.1, Volle F.1

1 - LSPM, France 2 - ENSTA, France

[email protected]

Earlier studies [1-3] have shown that polarizability effects may be important (the dipole moment of polar molecules in liquid phases may increase by 20-50%). However, these effects are usually not taken into account in thermodynamic models and only a few authors included them in an equation of state (EOS) [4-6]. This work is the beginning of a systematic study of the impact of polarizability effects on the phase equilibrium computations with the GC-PPC-SAFT model. A group contribution polar PC-SAFT EOS is here extended to include explicitly the polarizability contribution to the polar interactions between molecules. The extension is based on the theory of Wertheim [1,2] and Venkatasubramanian et al. [7,8]. The polarizable GC-PPC-SAFT EOS can be written in terms of the Helmholtz free energy as

AEOS = APC-SAFT + Apolar’,

where APC-SAFT is the original PC-SAFT EOS [9] and Apolar’ is a renormalized polar term obtained by modifying the original polar term Apolar of GC-PPC-SAFT (Twu and Gubbins’ term for spherical molecules combined with the segment approach of Jog and Chapman [10]). Apolar’ is a function of the total dipole moment µ’ and of the polarizability components α and α of the segments. The total dipole moment µ’ is computed self-consistently from its permanent value µ and the electric field E by

The new model is applied to systems containing alkyl-ether and alkane compounds and is compared to the non polarizable GC-PPC-SAFT model [11]. The parameters for the alkane series have been reused [12]. The polarizabilities of non-polar groups CH2, CH3 have been taken from previous studies [13,14]. The parameters for the ethers have been reconsidered in this work. The GC-SAFT parameters σO, RO, εO of group O and the polar segment fraction have been readjusted on pure compound data (vapour pressures and saturating liquid densities). The remaining parameters (permanent dipoles and polarizabilities) were taken from the literature [13-15]. Some results are given below. Some improvement is obtained by including polarizability in the GC-PPC-SAFT model.


0

1

2

3

4

5

DME MEE MPE MBE DEE DBE

%Pr

essu

re D

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w ith polarizabilityw ithout polarizability

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%Vo

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e D

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01

2345

67

DEE-C5 DEE-C6 MBE-C7 DBE-C7 DPE-C7

%Pr

essu

re D

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tion w ith polarizability

w ithout polarizability

2.7E+04

3.2E+04

3.7E+04

4.2E+04

4.7E+04

5.2E+04

0.5 0.7 0.9x,y (MBE)

P, P

a

with polarizabilitywithout po larizabilityexp

MBE-C7

0

1

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%Pr

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0

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DEE-C5 DEE-C6 MBE-C7 DBE-C7 DPE-C7

%Pr

essu

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evia

tion w ith polarizability

w ithout polarizability

2.7E+04

3.2E+04

3.7E+04

4.2E+04

4.7E+04

5.2E+04

0.5 0.7 0.9x,y (MBE)

P, P

a

with polarizabilitywithout po larizabilityexp

MBE-C7

Figure 1. Results on pure ethers and their mixtures with n-alkanes. Acknowledgment We gratefully acknowledge the ANR for support : ANR-09-CP2D-10-04 MEMOBIOL. References [1] M.S. Wertheim, Mol. Phys., (1977), 34, 1109–1129. [2] M.S. Wertheim, Mol. Phys., (1979), 37, 83–94. [3] M. Sprik, M.L. Klein, J. Chem. Phys., (1988), 89, 7556–7560. [4] B. Moser, K. Lucas, K.E. Gubbins, Fluid Phase Equilibria, (1981), 7, 153-179. [5] T. Kraska, E. Gubbins, Ind. Eng. Chem. Res., (1996), 35, 4727-4737. [6] M. Kleiner, J. Gross, AIChE Journal, (2006), 52, 1951-1961. [7] V. Venkatasubramanian, K.E. Gubbins, Mol. Phys., (1984), 52, 1411-1429 [8] C.G. Gray, C.G. Joslin, V. Venkatasubramanian, Mol. Phys., (1985), 54, 1129-1148. [9] J. Gross, G. Sadowski, Fluid Phase Equilib., (2000), 168, 183–199. [10] P.K. Jog, W.G. Chapman, Mol. Phys., (1999), 97, 307-319. [11] D. NguyenHuynh, A. Falaix, J.-P. Passarello, P. Tobaly, J.-C. de Hemptinne, Fluid Phase Equilibria, (2008), 264, 184-200. [12] S. Tamouza, J.-P. Passarello, P. Tobaly, J.-C. de Hemptinne, Fluid Phase Equilibria, (2003), 222-223, 67-76. [13] K.A. Bode, J. Applequist, J. Phys. Chem., (1996), 100, 17820-17824. [14] R. Bosque, J. Sales, J. Chem. Inf. Comput. Sci., (2002), 42, 1154-1163. [15] D. NguyenHuynh, J.-P. Passarello, P. Tobaly, J.-C. de Hemptinne, submitted to Fluid Phase Equilibria.


PI-3. High Temperature Vapour-Liquid Equilibria of Ethanol-Water Mixtures

Cristino A.F.1, Rosa S.C.S.1, Morgado P.2, Galindo A.3, Filipe E.J.M.2, Palavra A.M.F.2, Nieto De Castro C.A.1

1 - Departamento de Química e Bioquímica and Centro de Ciências Moleculares e Materiais, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal

2 - Departamento de Engenharia Química e Biológica and Centro de Química Estrutural, Instituto Superior Técnico, 1049-001 Lisboa, Portugal

3 - Department of Chemical Engineering and Centre for Process System Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K.

[email protected]

A flow apparatus especially designed to carry out accurate measurements of the properties of different phases in equilibrium, built and successfully tested by Rosa et al. [1], has been used to determine vapour-liquid equilibria at high temperatures. Changes in the equipment performance were introduced and will be described.

The water ethanol-system has been considered a possible reference system for this type of measurements and for which accurate data are available [2, 3]. Experimental results obtained between 363 and 424 K are compared with available literature data, and also with theoretical results obtained using the Statistical Associating Fluid Theory for potentials of Variable Range (SAFT-VR) [4, 5]. The molecular parameters used were taken from the work of Mac Dowell et al. [6], who optimized the unlike interaction parameters using literature data for six isobars between 1.2 and 20.7 bar. The phase equilibria, has proved to be accurately described with this approach, especially considering that the parameters are being applied to a larger region of the phase diagram.

a)

b)

Figure 1. Isotherm of the pressure composition (Px) vapour-liquid equilibria at constant temperature a) 363.2 K and b) 423.7 K. The continuous curves represent the SAFT-VR description and the symbols the corresponding experimental data.[1]


References [1] S.C.S. Rosa, C.A. Nieto de Castro, A.M.F. Palavra, Proceedings of 4th Asian Thermophysical Properties Conference, (1995), 467-470. [2] V. Niesen, A.M.F. Palavra, A.J. Kidnay, V.F. Yesavage, Fluid Phase Equilibria, (1986), 31, 283-298. [3] B. Kolbe, J. Gmehling, Fluid Phase Equilibria, (1985), 23, 213-226. [4] A. Gil-Villegas, A. Galindo, P.J. Whitehead, S. Mills, G. Jackson, A.N. Burgess, J. Chem. Phys., (1997), 106, 4168-4186. [5] A. Galindo, L. Davies, A. Gil-Villegas, G. Jackson, Mol. Phys., (1998), 93, 241-252. [6] N. Mac Dowell, F. Llovell, C.S. Adjiman, G. Jackson, A. Galindo, Ind. Eng. Chem. Res., (2010), 49, 1883-1899.


PI-4. Predicting second-order derivative properties with a modified SAFT-CP equation of state

De Villiers A.J., Schwarz C.E., Burger A.J.

Department of Process Engineering, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa

[email protected]

SAFT-CP [1] is a modified variant of the original SAFT model. It uses the hard convex body [2] term as reference fluid, and accounts for chain dispersion with a new term. The initial aim of the model was to provide good estimates of derivative properties in the critical region. The model has proven to be a successful pure component equation of state (EOS) for first-order properties, close to and far from the critical region. SAFT-CP has also been applied to several second-order derivative properties such as speeds of sound [2], heat capacities [2] and Joule-Thompson coefficients [3]. At low temperatures on the saturation curve, however, anomalies are observed in the prediction of some second-order properties: the prediction of the model rapidly diverges from the experimental data. The aim of this work is to address this problem. Two modifications are made to the original SAFT-CP model: a) replace the conventional temperature dependency of the segment diameter with the temperature dependency used in the MOBACK EOS [5], and b) replace the original dispersion term of Chen and Kreglewski [6] with the dispersion term used in MOBACK [5]. The MOBACK dispersion term is also in the Alder [7] form and the universal model constants were originally fitted to ethane data [5]. Since the hard convex body term does not approximate molecules as spheres, using ethane data to determine model constants in the dispersion term is more appropriate, because the ethane molecules are more like hard-convex-bodies. The modified SAFT-CP (mod SAFT-CP) model provides improved results for most second order properties in the low temperature region and the same anomalies as encountered with the original SAFT-CP models is not observed.

References [1] J. Chen, J. Mi, Fluid Phase Equilib. 186 (2001), 165-184. [2] T. Boublik, J. Chem. Phys. 63 (1975) 4048. [3] A. Maghari, M. Sadeghi, Fluid Phase Equilib. 252 (2007) 152-161. [4] A. Maghari, Z. Safaei, S. Sarhangian, Cryogenics 28 (2008) 48-55. [5] B. Saager, R. Hennenberg, J. Fischer, Fluid Phase Equilib. 72 (1992) 41-66. [6] S.S. Chen, A. Kreglewski, Ber. Bunsen-Ges. Phys. Chem. 81 (1977) 1048. [7] B.J. Alder, D.A. Young, M.A. Mark, J. Chem. Phys. 56 (1972) 3013.


PI-5. Application of Artificial Bee Colony optimization algorithm in phase behavior calculations

Tahooneh A.1, Yazdizadeh M.2, Eslamimanesh A.3, Mohammadi A.H.3, Richon D.3

1 - Department of Mathematics, College of Science, Shiraz University, 71348-51154, Shiraz, Iran

2 - Chemical Engineering Department, School of Chemical and Petroleum Engineering, Shiraz University, 1348-51154 Shiraz, Iran

3 - MINES ParisTech, CEP/TEP - Centre Énergétique et Procédés, 35 Rue Saint Honoré, 77305 Fontainebleau, France

[email protected]

The optimum values of a number of thermodynamic model parameters are generally obtained by appropriate optimization methods. Almost all of the traditional optimization algorithms have the possibility of getting trapped at local optimum, depending on the degree of non-linearity and the initial guess. There is no guarantee for these optimization methods to find the global optimum solution, however, the population-based search algorithms are supposed to do so. The Artificial Bee Colony (ABC) algorithm is a meta-heuristic optimization strategy based on the intelligent behavior of honey bee swarms. In this work, the ABC algorithm is applied in phase behavior calculations/predictions of different systems encountered in chemical engineering processes. The obtained results are finally compared with some of the most popular population-based optimization techniques in the literature.


PI-6. Thermodynamic model for predicting dissociation conditions of gas hydrates in porous media

Eslamimanesh A., Mohammadi A.H., Richon D.

MINES ParisTech, CEP/TEP - Centre Énergétique et Procédés, 35 Rue Saint Honoré, 77305 Fontainebleau, France

[email protected]

Natural gas hydrates in sediments are generally dispersed in pores, muds and clays, or fractures in geological formations. These phenomena inhibit hydrate formation and change the hydrate stability conditions. Capillary inhibition of hydrate stability in pores has been considered as a possible reason for differences between the predicted and actual boundary of hydrate stability zones. In this work, a simple thermodynamic model has been developed based on the equality of water fugacity in the liquid water and hydrate phases. The solid solution theory of van der Waals-Platteeuw (vdW-P) along with the Gibbs-Thomson relationship (to determine the interfacial tension between hydrate and water) is applied to calculate the fugacity of water in the hydrate phase. The results of this model are compared with selected experimental data from the literature. It is shown that the predictions of the new proposed model agree well with these investigated experimental data.


PI-7. Thermodynamic Consistency Test of Experimental Phase Equilibrium Data: is it Really a Necessary Step?

Eslamimanesh A., Mohammadi A.H., Richon D.


[email protected]

Measurements of experimental phase equilibrium data should be done deliberately to obtain reliable data for tuning especially adapted thermodynamic models. High uncertainties of such data have several reasons including low concentrations (traces) of some components in related phases, very high or very low temperatures and/or extreme pressures, experimental procedures, design of experimental apparati, errors in calibrations of temperature probes and pressure transducers, possible errors during the measurements, failing instruments etc... Consequently, we are allowed to be not fully confident regarding experimental data that have been obtained without significant repeatability and reproducibility tests and not through various experimental equipment and methods for comparisons. As a bad process designs can lead to big losses of time and money, it is highly recommended to perform thermodynamic consistency tests on available literature data. The thermodynamic relationship, which is frequently used to analyze thermodynamic consistency of experimental phase equilibrium data is the fundamental “Gibbs-Duhem equation”. In this work, consistency of the phase equilibrium data of several significant systems encountered in chemical and petroleum industries are tested. The investigated systems include water content of methane in equilibrium with gas hydrate, liquid water or ice, sulfur content of hydrogen sulfide vapor, solubility data of carbon dioxide and methane with water inside and outside gas hydrate formation region, solubility of waxy compounds in natural gas systems, and phase behaviors of mixtures of supercritical carbon dioxide + various ionic liquids . The results demonstrate the clear necessity of such consistency tests and justify our recommendation done few lines before.


PI-8. Determination of Physical Properties using Group contribution Strategies: Suggestions and Modifications

Gharagheizi F.1, Eslamimanesh A.2, Mohammadi A.H.2, Richon D.2

1 - Department of Chemical Engineering, Faculty of Engineering, University of Tehran, P.O. Box 11365-4563, Tehran, Iran


[email protected]

Calculations/predictions of physical properties of pure chemical compounds are useful for chemical industries to reduce their effort regarding experimental data acquisitions (that generally lead to high costs, time consumption , and to possible experimental difficulties). Consequently, predictive tools are generally expected to deal with calculations/predictions of physical properties of chemical compounds. However, accurate knowledge of some thermodynamic properties is necessary prior to developing adequate and convenient models with for example adjustable group parameters or simply to check for reliability of any predictions through entirely predictive models. Application of classical Group Contributions (GC) method has been of great interest for this purpose. However, the capabilities of this technique and significant points, which should be considered during the calculations by such algorithm are generally ignored. In this work, we point out several problems encountered during the calculations using classical GC method and present the recently-proposed Artificial Neural Network-Group Contribution (ANN-GC) strategy. In addition, the advantages of the later technique over the classical one are investigated. The capabilities of ANN-GC method are finally checked by calculations/predictions of several significant physical properties for chemical industries.


PI-9. Prediction of hydrogen sH hydrate phase boundary in the presence of alkanes, alkenes, alkynes and cycloalkanes

promoters

Babaee S.1, Hashemi H.1, Javanmardi J.1, Eslamimanesh A.2, Mohammadi A.H.2

1 - Department of Chemical Engineering, Shiraz University of Technology, 71555-313, Shiraz, Iran


[email protected]

Hydrogen is a versatile molecule, which can be used as a source of future energy. There are three types of technologies for hydrogen storage: compression, liquefaction, and storage in solid materials. A new method for hydrogen storage investigated recently is use of clathrate hydrates for this purpose. There are two advantages in employing hydrate formation as a means for storage and transportation. At the first place, a much lower storage space is needed. Secondly, the safety of the process is improved. Gas hydrates are crystalline solids composed of water and some molecules of suitable size at appropriate conditions of temperature and pressure. The guest molecules are trapped in cavities of hydrogen-bonded water molecules. Different clathrate hydrate structures have been known including structures I, structures II, and structure H. In this work, hydrogen structure H (sH) hydrate phase equilibria in the presence of eleven promoters including n-alkanes, n-alkenes/alkynes, and cycloalkanes is predicted. The van der Waals–Platteeuw (vdWP) model is applied for prediction of the hydrate phase. In addition, the potential functions of hydrate formers are represented using the Kihara potential model for spherical molecules. The phase equilibria of hydrogen + water mixture is predicted using Valerama Patel Teja (VPT) equation of state (EoS) with Non Density Dependent (NDD) mixing rule. Due to the lack of experimental solubility data of hydrogen in these promoters, equilibria of the hydrogen + promoters systems are modeled using EoS-GE along with the UNIFAC activity model and the modified Huron Vidal (MHV) mixing rule. The obtained results show reasonable agreement with the experimental data. Finally, the hydrogen storage capacity of hydrate in the presence of various promoters in structure H is predicted as well as the occupancies of the hydrate cavities.


PI-10. Phase Equilibria of Semi-Clathrate Hydrates of Tetra-n-butyl ammonium bromide + Mixtures of Carbon Dioxide

with methane, nitrogen, hydrogen

Mohammadi A.H., Eslamimanesh A., Belandria V., Richon D.


[email protected]

Tetra-n-butyl ammonium bromide (TBAB) is a quaternary ammonium salt recently used as a semi-clathrate (sc) hydrate former. As sc hydrates have the capability to include different molecules, therefore they can be regarded as a means for storage and separation of gases. The presence of TBAB in aqueous solution is expected to reduce the pressure required for gases hydrate formation and is therefore interesting on economic point of view. Unfortunately, the thermodynamic properties of TBAB sc hydrates in the presence of gas mixtures have scarcely been studied, while accurate knowledge of phase equilibria of hydrates of mixtures of gases in TBAB aqueous solutions as a function of TBAB concentration is necessary to optimized designs the gas storage/separation processes based on hydrate crystallization. In order to provide useful data, we have used specially designed equipment based on “static-analytic” and “isochoric pressure-search” methods with constant volume cell. Experimental dissociation data for the sc hydrates of TBAB + mixtures of carbon dioxide with methane, nitrogen, and hydrogen are reported at various temperatures and concentrations of tetra-n-butylammonium (5 to 40 mass %).


PI-11. Modulation of Hydrophobicity of Surfactant Tail by Specific Salt and its Role in Self-Assembly of an Ionic Micelle

Koroleva S.V., Victorov A.I.

Department of Chemistry, Saint Petersburg State University, Universitetsky pr. 26, Petrodvoretz, 198504, Saint Petersburg, RUSSIA

[email protected]

The nature and concentration of salt in solution of an ionic surfactant are important factors that may cause micellar shape transformations (including sphere-to-rod transitions, branching and formation of spatial networks), gelation and phase split. The effects of specific chemistry of salt (reflected by the Hofmeister series) on the morphology of aggregated nanostructures has not been captured quantitatively until now.

A plausible theoretical approach [1-2] has been proposed for colloids based on the Lifshitz theory of dispersion interactions. In our work we apply this approach to aqueous solution of an ionic surfactant and salt. The micellization is described using a modified version of the Nagarajan-Ruckenstein model. The dispersion interactions of ions with the micelle core depend on ionic polarizability that reflects the specificity of ion [2-4]. These interactions are taken into account directly as an additional term in the free energy of micellization and also indirectly through the effect of these interactions on the electrostatic potential of the electrical double layer.

Experimental data on critical micelle concentration (CMC) in presence of different salts show that at low salinity the effect of specific salt is a shift of the logCMC-salinity curve. At high salinity this curve tends to warp downward. This deviation from linearity may be stronger or weaker depending on specific salt.

Our model has been applied to aqueous solutions of a cationic surfactant (alkyltrimethylammonium-X, alkylpyridinium-X; X= Cl-, Br-, I-) or an anionic surfactant (M-alkylsulfate; M= Li+, Na+, K+, Rb+, Cs+) in presence of different salts. Figure 1 shows an example of calculated CMC. At low salinity our model reflects correctly the shift of the CMC owing to the change of counterion. Figure 1 also shows the results from the original version of the Nagarajan-Ruckenstein model that fails to describe the effect of specific ion.

From the available data on solubility of hydrocarbons in aqueous solutions of different salts we estimated the effect of specific salt on the free energy of transfer of surfactant tail in the micelle core. This salt-dependent hydrophobic term has been used in the original version of the Nagarajan-Ruckenstein model that does not take into account the dispersion interaction of ions with the micelle. For low salinity, calculated results show almost no effect of specific salt on CMC. We thus may conclude that the dispersion


interaction of ions with the micelle has more significant role in manifesting ion specificity than the modulation of the hydrophobicity of surfactant tail by specific salt.

For financial support the authors are grateful to Saint-Petersburg State University, project #12.37.127.2011, to the Russian Foundation for Basic Research, project #09-03-00746-a.

0,01 0,1 1

10-5

10-4

10-3

10-2

TTAC

Nagarajan,δ=0.20nm Nagarajan,δ=0.16nm This work

log(

CM

C)

Csalt, M

TTAB

Figure 1. Log CMC vs. salinity in aqueous solution of surfactant with different salts. Experiment: () tetradecyltrimethylammonium bromide (TTAB) + NaBr;() tetradecyltrimethylammonium cloride (TTAC) + NaCl. Calculation: ( , ) Nagarajan-Ruckenstein model with different anionic radii δ; ( ) Model proposed in this work; dispersion constants [1024J·nm3]: 44.4 (Br-), 35.8 (Cl-), 4.54 (Na+); δCl=0.18nm; δBr=0.16nm. Cross-section area of head group ap=0.70nm2

References [1] F.W. Tavares, D. Bratko, J.M. Prausnitz. Curr.Op.Coll.Interface Sci. 9 (2004) 81. [2] M. Bostrom, F.W. Tavares, D. Bratko, B.W. Ninham. J.Phys.Chem. B109 (2005) 24489. [3] Parsons, D. F.; Deniz, V.; Ninham, B. W. Colloids and Surfaces A, 343 (2009) 57. [4] Parsons, D. F.; Ninham, B. W. Langmuir, 26 (2010) 1816.


PI-12. Assessment of Asphaltene Stability in Crude Oils Using New Colloidal Stability Index

Likhatsky V.V., Syunyaev R.Z.

Gubkin Russian State University of Oil and Gas

[email protected]

Many processes and phenomena occurring in crude oils can be explained if we consider that crude oils are colloidal systems [1]. In such systems, asphaltenes and resins comprise the dispersed phase, while saturates and aromatics are the continuous phase. Asphaltene precipitation is a serious problem for the petroleum industry, since asphaltenes form deposits on wells, tubing, piping, and also during refining processes.

Various colloidal stability indices are applied for evaluating the behavior of asphaltenes in crude oil. Such indices use information on crude oil composition. The following colloidal index (CI) [2] is cited as an example

asphaltenes[wt %] + saturates[wt %]CIresins[wt %] + aromatics[wt %]

= (1)

Many authors point to the fact that such indices are unsuitable for this purpose [3]. The reason is that the asphaltene precipitation depends not only on the composition of crude oils, but also on many other factors, namely, physicochemical properties of the dispersed phase and the continuous phase, temperature and pressure.

Asphaltene precipitation is determined by the polarity of asphaltenes. However, it should be appreciated that, in crude oils, orientation interactions of asphaltenes will depend not only on the polarity of asphaltenes themselves, but also on the polarity of other crude oil components. This refers primarily to resins.

The new colloidal stability index (NCSI), which takes into account the orientation interactions between the crude oil components, can be expressed as follows

asp sat

res arom

asphaltenes[wt %] + saturates[wt %]NCSIresins[wt %] + aromatics[wt %]

ε εε ε

⋅ ⋅=⋅ ⋅

(2)

where εasp, εsat, εres, and εarom are the dielectric constant (ε) of asphaltenes, saturates, resins, and aromatics, respectively.

To test the new colloidal stability index, sixteen crude oils with known SARA (saturates, aromatics, resins, and asphaltenes) compositions were selected from ref [3]. Eight crude oils were classified as unstable, and the other eight were classified as stable.

Figure 1 depicts calculated indices for the studied crude oils. As Figure 1a suggests, the index corresponding to eq 1 is not able to determine asphaltene stability, that is, there is not a clear relationship between composition and stability of the studied crude oils at the


oilfield. The new index (eq 2, Figure 1b) correctly classifies 15 of the 16 crude oils. Thus, with the new index, it is possible to estimate asphaltene stability in crude oils. If, the new index is more than 0.95 for crude oil under study, then asphaltene precipitation and deposition will occur, and the crude oil will be unstable. If the index is less than 0.95, then the crude oil will be stable, and the risk of asphaltene precipitation and deposition will be minimal.

Figure 1. Calculated indices for the unstable (filled squares ) and stable (open circles ) crude oils under study: (a) with eq 1, (b) with eq 2. To use this new index, it is necessary to collect certain statistics, that is, to investigate stable and unstable crude oils and to determine the appropriate values of the index. In the future, new crude oils can be characterized by comparing them with known samples.

References [1] O.C. Mullins, E.Y. Sheu, A. Hammami, A.G. Marshall, eds., Asphaltenes, Heavy Oils, and Petroleomics, Springer, New York, 2007. [2] L. Loeber, G. Muller, J. Morel, O. Sutton, Fuel, (1998), 77, 1443-1450. [3] E. Rogel, O. León, E. Contreras, L. Carbognani, G. Torres, J. Espidel, A. Zambrano, Energy Fuels, (2003), 17, 1583-1590.


PI-13. Kinetics and thermodynamics of asphaltene adsorption on iron

Safieva J.O.1, Syunyaev R.Z.2

1 - Emanuel institute of Biochemical Physics Russian Academy of Sciences 2 - Gubkin Russian State University of Oil and Gas

[email protected]

Asphaltene deposition is responsible for many problem situations during oil production and processing. The limited knowledge about asphaltene-metal interactions hinders a development of mitigation techniques. The knowledge of kinetic and thermodynamic parameters of adsorption in perspective opens a way for physical and chemical engineering of liquid-solid interfaces in the oil industry.

In the present study, cast steel shot was used as an adsorbent for the adsorption of asphaltenes dissolved in different model oils at standard conditions. The adsorption parameters of native and visbroken residue asphaltenes were estimated using near-infrared (NIR) spectroscopy. Quantity of adsorbed asphaltenes was determined by measuring the transmittance spectra of the bulk phase above the adsorbent. Employed experimental scheme is described in our work [1]. The maximal adsorbed mass density, the adsorption equilibrium constant, the adsorption/desorption rate constants were calculated under controlled process parameters such as initial asphaltene concentration in the range of 0.01-3 g/L, adsorbent particle size (0.5, 1.4, and 3.6 mm), the source of the petroleum system from which asphaltenes were obtained (West-Siberian crude oils and visbroken products), model oil system composition, asphaltene extraction procedure. The results of the adsorption isotherms show that the adsorption process in a chosen concentration range can be well described in most cases with the Langmuir model. The parameters obtained from Langmuir model should be considered as effective ones. Kinetic studies show that desorption rate appeared to be much lower than the adsorption rate in all examined systems. Adsorption of asphaltenes on metal was found to be almost irreversible.

Capillary aggregation effect was detected, when comparing values of maximal adsorbed mass densities of adsorption systems with steel shot of different sizes (see Figure 1). Maximal adsorbed mass density and Gibbs energy values increased in adsorbent series r=3.6mm < r=1.4mm < r=0.5mm. The first step of the adsorption process is the filling of micropores that are associated with particle surface roughness. After the micropore saturation, the contact points of neighboring particles become centers of adsorption. Increasing quantity of these contacts in a volume unit of adsorbent results in its adsorption potential enhancing. These points have the maximal surface curvature. According to the Kelvin-Thomson equation, this leads to the acceleration of the monomer aggregation process. For gas adsorption on porous media, this effect is commonly known as capillary condensation. An analogous effect in solutions can be


named as capillary aggregation. Adsorbed gel-like layers are formed rapidly near contact points. The formation of these layers initiates the colmatage process in porous media. Permeability will decrease with growth of such layers, following the reduction of the effective diameter of capillaries. Quantity of these contacts in a volume unit is maximal for fine-grained fractions.

Figure 1. Capillary aggregation effect. Adsorption capacity values for systems with high- grained adsorbent (0.5 mm) were still higher than for systems with middle-grained adsorbent (1.4 mm), however these values are unexpectedly close. Possible explanation is the presence of areas in adsorbent structure that were not involved in adsorption process. ”Dead” zones may occur due to capillary aggregation effect reported earlier [1]. The conclusion about primarily role of the pore volume and diameter of the adsorbent in governing the adsorption [2] is confirmed. Surface area of adsorbent appeared not to be a key parameter.

Gibbs energy values correspond to the physical process. Energy of asphaltene adsorption on metal surface (Gibbs potential) was higher, in the same order of magnitude as the adsorption of asphaltenes on mineral [1].

Visbroken asphaltene adsorption rate values were higher in comparison with native asphaltenes. Phase behavior, hence adsorption behavior of asphaltenes in model oils were influenced by the quality of solvent. Asphaltene extraction procedure is significant: different compositions of extracted material influence the kinetic and thermodynamic parameters of adsorption.

References [1] Syunyaev R.Z. et al. Energy&Fuels 2009 23 (3), pp 1230-1236. [2] Lopez-Linares F. et al. Energy&Fuels 2009 23 (4), pp. 1901-1908.


PI-14. Vapour-liquid equilibria on the carbon dioxide - aqueous solutions systems from 293 to 393 K: experiments

and modeling

Lucile F.1,2, Cezac P.2, Contamine F.2, Houssin-Agbomson D.1, Arpentinier Ph.1, Baudouin O.3

1 - Air Liquide - Claude-Delorme Research Center, France 2 - LaTEP - ENSGTI, France

3 - PROSIM, France

[email protected]

Process engineering constantly needs new research regarding properties of gases, liquids and solids. Indeed, thermodynamic properties like enthalpy and calculations of phase equilibria are at the heart of computer-aided process engineering tools, for design and optimization of processes in any area of application. The purpose of this paper is the characterization of the behavior of gaseous CO2 with aqueous solutions under pressure at thermodynamic equilibrium. Studies exist on CO2-water system: e.g. Zel’vinskii 1937, Chapoy et al. 2004, Valtz and Chapoy 2004, Dalmolin et al. 2006.The present work extends experimental data on a wider temperature and pressure range for CO2-H2O system and study CO2 behavior in aqueous solution containing NaOH. In order to study this kind of systems with an acceptable accuracy at thermodynamic equilibrium, a specific apparatus – based on a well-stirred equilibrium cell at constant temperature – was designed and validated on existing data. Temperature is strictly controlled and regulated, and initial pressure is given by the amount of carbon dioxide loaded in the cell.

When equilibrium is reached, solubility of CO2 in the aqueous phase is measured with an ion chromatograph. A thermodynamic modeling approach for CO2 solubility calculation based on Edwards et al. 1975 electrolytic model – available in Simulis Thermodynamics Software – is proposed. It will be enhanced using new experimental data obtained in this work.

References [1] Chapoy A, Mohammadi AH, Chareton A, Tohidi B, Richon D, Eng. Chem. Res 43 (2004) 1794-1802. [2] Dalmolin I, Skovroinski E, Biasi A, Corazza ML, Dariva C, Oliveira JV, Fluid Phase Equilibria 245 (2006) 193-200. [3] Edwards TJ, Newman J, Prausnitz JM, AiChE Journal 21, 2 (1975) 248-259. [4] Valtz A, Chapoy A, Fluid Phase Equilib. 226 (2004) 333-344. [5] Zel’vinskii YD, Zhurn. Khim. Prom. 14 (1937) 1250-1257.


PI-15. An Electrolyte CPA Equation of State for Applications in the Oil and Gas Industry

Maribo-Mogensen B., Kontogeorgis G.M., Thomsen K.

Center for Energy Resources Engineering (CERE), Department of Chemical and Biochemical Engineering, Technical University of Denmark (DTU)

[email protected]

The recovery of natural gas from underground reservoirs is an essential process to the oil- and gas industry [1]. Besides smaller hydrocarbons, the raw natural gas from the well can contain large amounts of injected salt water for enhanced oil recovery. Since gas hydrates may easily form under the low temperatures and high pressures encountered during transportation through the pipeline to the natural gas processing facility, large amounts of thermodynamic inhibitors (such as methanol) are added at the well head [1]. The presence of electrolytes typically decreases the solubilities of gases in water-hydrocarbon mixtures (salting-out effect), and may also enhance the inhibitory effect of methanol and glycol on the formation of gas hydrates in natural gas pipelines, thereby ensuring unobstructed flow [1] (see Fig. 1):

Figure 1. Experimental and predicted pressures for gas hydrate formation from methane in aqueous sodium chloride solutions. [2]

The accurate prediction of the phase behaviour of the complex mixtures of hydrocarbons, water, salts and gas hydrate inhibitor is important to the oil- and gas industry in order to perform process optimization, minimize cost and furthermore reduce the environmental impact [1]. The CPA (Cubic Plus Association) equation of state (EoS) has been very successful in modelling the phase behaviour of mixtures containing natural gas and associating/polar compounds [4, p. 261] (see Fig. 2):


Figure 2. CPA predictions of hydrate dissociation temperatures for a natural gas mixture with different amounts of hydrate inhibitor [3].

It is developed as an extension to the SRK (Soave-Redlich-Kwong) EoS where an additional term has been added to account for intermolecular association [4, p. 263]:

( )( ) ( )1 ln1 1

2 i

i

i Ai Am m m m

a TRT RT gP x XV b V V b V

ρρ

∂= − − + − − + ∂ ∑ ∑ (1)

Where P is the pressure, R is the ideal gas constant, mV is the molar volume, b is the cross co-volume parameter, a is the cross energy parameter, ρ is the molar density, ix is the mole fraction of component i ,

iAX is the fraction of sites A on molecule i that is not bonded to other sites. a and b are calculated using the van der Waals one-fluid mixing rules using an optionally temperature dependent interaction parameter ijk .

iAX is related to the association strength i jA B∆ between the two sites A and B on two different molecules i and j [4, p.263]:

1 1 i j

i j

j

A BA j B

j BX x Xρ− = + ∆∑ ∑ (2)

The association strength is calculated using the association energy parameter i jA Bε and i jA Bβ calculated using either the CR-1 or the Elliott combining rules [4, p. 264].

This work extends the CPA EoS to include a (primitive) term accounting for the long-range electrostatic interactions, and investigates the performance of the electrolyte-CPA EoS based on the Debye-Hückel model [4, p. 470-471]. Furthermore, a Born term is included to account for the solvent-ion interactions [4, p. 471]. The model is checked for prediction of salting out curves for e.g. the sodium chloride-water-methane system.

References [1] E. Hendriks, Applied Thermodynamics in Industry, a pragmatic approach, Fluid Phase Equilibria (2010), In Press, Corrected Proof. [2] P. Englezos, P. R. Bishnoi, AIChE 34 (2004), 1718-1721. [3] H. Haghighi, A. Chapoy, R. Burgess, S. Mazloum, B. Tohidi, Fluid Phase Equilibria 278 (2009), 109-116. [4] G. M. Kontogeorgis, G. K. Folas, Thermodynamic Models for Industrial Applications - From Classical and Advanced Mixing Rules to Association Theories, Wiley, 2010.


PI-16. Phase Behaviour Modelling of Chemical Reactions in Dense and Supercritical Carbon Dioxide using the Cubic-

Plus-Association Equation of State

Musko N.E.1,2, Kontogeorgis G.M.1, Grunwaldt J.-D.2, Tsivintzelis I.1

1 - Center for Energy Resources Engineering (CERE), Department of Chemical and Biochemical Engineering, Technical University of Denmark (DTU), DK-2800 Kgs. Lyngby,

Denmark 2 - Institute of Technical Chemistry (ITCP and IKFT), Karlsruhe Institute of Technology (KIT),

D-76128 Karlsruhe, Germany

[email protected]

Introduction Heterogeneous catalysis combined with the use of supercritical carbon dioxide (scCO2) as a reaction medium provides a number of opportunities to intensify many chemical reactions due to the unique properties of the supercritical fluid, which combine both gas- and liquid-like properties [1]. Thus, as any gas scCO2 significantly decreases heat and mass transfer limitations in the process and its relatively high density and solubility (liquid-like properties), on the other hand, allow using it as a cheap, recyclable and environmentally benign alternative to conventional solvents. The properties of dense and supercritical CO2 are strongly dependent on the pressure and temperature in the system, which makes both the chemical and separation processes quite tuneable. Therefore, phase behaviour plays an important role not only during the chemical reaction, as it determines the regime of the process (single or multi phase), but it is also important for the following process of yielding the target product from the reaction mixture. Phase behaviour, especially during a chemical reaction, is quite difficult to monitor and investigate experimentally; however, there are a large number of techniques which allow studying it in binary and multicomponent mixtures [2] and also in situ during chemical reactions [3]. Nevertheless, instrumental investigations are often time consuming and expensive. An attractive alternative to that is the theoretical modelling of the phase behaviour and many other thermodynamic properties of the system. Thermodynamic models are capable not only of describing experimental data, but also predicting many features of the system, which can be used for the following optimisation and improvement of the process [4]. Model One of the advanced thermodynamic models is the Cubic-Plus-Association Equation of State (CPA) [5]. The model can be used for a wide variety of systems under various conditions, including supercritical. In the case of simple systems comprising non-polar, non-associating components the CPA model reduces to the classical Soave-Redlich-


Kwong (SRK) EoS; however, if polar, strongly associating components with hydrogen bonding are present in the system, the association term of the CPA correlates effectively the non-ideality for many mixtures. The aim of this work is to apply the CPA model to the systems of heterogeneously catalysed chemical reactions in dense carbon dioxide in order to optimise the reaction conditions and, thereby, intensify the overall process. Reaction Systems The selective hydrogenation of 2-butenal to butanal in scCO2 is the first step of the “one-pot” synthesis of 2-ethylhexenal-2, the product of aldol reaction of butanal [6]. In this system the concentration of hydrogen is decreasing over time, whereas the concentration of carbon dioxide stays constant. Therefore, the dissolution power of CO2 is increasing. The phase equilibria are important in this case as carrying out the reaction in one phase region is more favourable for hydrogenation with molecular hydrogen compared to the two phase reaction. Camy et al. [7] reported about the synthesis of dimethylcarbonate (DMC) from methanol and carbon dioxide. The SRK equation of state was used for modelling the system. Afterwards, optimisation of the reaction conditions was performed based on the modelling results. The authors claimed that SRK gave satisfactory results, even though in some cases quite significant deviations from the experimental data were observed. The system comprises two strongly associating components, forming hydrogen bonds; methanol and water. For such systems operated under supercritical conditions the CPA model provides better results to describe the phase behaviour and consequently rational process optimisation. The examples show that knowledge of phase behaviour is important to provide guidelines for the optimisation of the target reactions. A more rational approach can be provided using modelling whereby the Cubic-Plus-Association Equation of State is of significant importance. References [1] A. Baiker, Chem. Rev., Washington, D. C., (1999), 99, 453. [2] J.M.S. Fonseca, R. Dohrn, S. Peper, Fluid Phase Equilib., (2010), 228, 1 – 54. [3] J.-D. Grunwaldt, R. Wandeler, A. Baiker, Catal. Rev. Sci. Eng., (2003), 45, 1 – 96. [4] G.M. Kontogeorgis, G.K. Folas, Thermodynamic Models for Industrial Applications: from classical and advanced mixing rules to association theories, Wiley, 2010. [5] G.M. Kontogeorgis, E.Voutsas, I. Yakoumis, D.P. Tassios, Ind. Eng. Chem. Res., (1996), 35, 4310 – 4318. [6] T. Seki, J.-D. Grunwaldt, N. van Vegten, A. Baiker, Adv. Synth. Catal., (2008), 350, 691 – 705. [7] S. Camy, J.-S. Pic, E. Badens, J.-S. Condoret, J. Supercrit. Fluids, (2003), 25, 19 – 32.


PI-17. Pressure Effect on Phase Behavior of Surfactant System

Sandersen S.B.1, Von Solms N.S.1, Stenby E.H.2

1 - Center for Energy Resources Engineering, Department of Chemical & Biochemical Engineering, Technical University of Denmark

2 - Center for Energy Resources Engineering, Department of Chemistry, Technical University of Denmark

[email protected]

Introduction It is expected that many mature oil reservoirs still have more than 50 % remaining crude oil trapped, which cannot be recovered by primary nor secondary recovery techniques. As oil recovery potential is still expected for these reservoirs Enhanced Oil Recovery (EOR) is introduced and in this work by surfactant flooding. Surfactant flooding is basically a technique where appropriate surfactants are injected into the reservoir to reduce the interfacial tension (IFT) between crude oil and water.

This work handles the present phase behavior of surfactant-oil-brine systems at reservoir conditions, which is at elevated pressures and temperatures. From literature studies it is understood that mixed surfactant systems are most commonly used for surfactant flooding as this result in the most efficient increase in oil recovery. However, when mixed surfactants are used this raises new obstacles, as the surfactant blend will undergo chromatographic separation down through the reservoir and thereby change composition during the flooding operation, which finally makes it difficult to predict the actual recovery outcome. Therefore it is preferable with simple surfactant systems and if possible potential single component surfactant systems are the most optimal solution for this oil recovery technique. As this approach is an expensive recovery method, as it will be large amounts of surfactant (or chemicals) required for the operation, this technique must be well understood before integrated into the oil plants.

Phase Behavior This work considers the understanding of the effect of pressure on the phase behavior of the brine/surfactant/oil system. For this study a model system is chosen; Water in Sodium Chloride/Sodium Dodecyl Sulphate (SDS)/1-Butanol/Heptane, which have been studied previously at room temperature and at atmospheric pressure [2]. The general understanding of pressure effect on such systems is that pressure does not have an effect on the phase behavior. However, this is debatable according to literature.

This work is entirely experimental, where the model system is examined in high pressure equipment using a DBR JEFRI PVT cell, which allows a wide range of different temperatures and pressures. Furthermore the system can be observed through a


window in the equipment and thus the increase or decrease in phase volumes and number of phases can be followed.

The experimental work is carried out at temperatures from 40-50˚C and at pressures from 1 to 400 bars. The initial and final composition of the system is given in table 1. During process the heptanes is added to the system, which is why composition change during experimental work.

Table 1. Initial and final composition of brine/surfactant/oil-system in wt% Water NaCl SDS 1-butanol heptane 0.616 0.043 0.025 0.051 0.265 0.532 0.037 0.022 0.044 0.365

The present system starts as a 3 phase system both in its initial composition and at the final. However, it is observed that as pressure is increased the system goes towards and 2 phase system when equilibrated. The system does also show sensitivity to temperature increase as would be expected, where an increase in temperature forces the system to a 2 phase system.

Conclusion The aim is to study the phase behavior of the present model system. The model system has already been studied and room temperature and this work examine the system at elevated pressures and temperatures.

As the pressures range is 1-400 bars, which is common at reservoir conditions, this is highly relevant to oil recovery processes and surfactant flooding.

References [1] B.M O’Brian, Journal of American Chemists’ Society, (1982), 59, 839a-852s. [2] J. van Nieuwkoop and G. Snoei, Journal of Colloid and Interface Science, (1984), 103, 400-416.


PI-18. Modeling of Mixtures with Acid Gases using the CPA Equation of State

Tsivintzelis I.1, Kontogeorgis G.M.1, Michelsen M.1, Stenby E.H.2

1 - Technical University of Denmark, Department of Chemical and Biochemical Engineering, Denmark

2 - Technical University of Denmark, Department of Chemistry, Denmark

[email protected], [email protected]

The phase behavior of mixtures containing acid gases (H2S and CO2) was investigated using the CPA equation of state [1] in order to suggest an engineering approach for the thermodynamic modeling of such systems.

Binary, ternary and multicomponent mixtures of acid gases with water, alcohols, glycols and hydrocarbons were investigated. Three approaches were used. Firstly, acid gases were modeled as non-associating (inert) compounds. In a second step, cross-association interactions between acid gases and water, alcohol and glycols were assumed. Finally, the potential of modeling acid gases as self-associating fluids was investigated. In the last two approaches, effort has been made in order to incorporate in the model experimental and theoretical (obtained from various ab-initio calculations) values for the strength of cross-association interactions between acid gases and water or alcohols.

0 50 100 150 2000.000

0.002

0.004

0.006

0.008

0.010

H2O

mol

e fra

ctio

n

Pressure / bar

T=298.15 K

Figure 1. Water content of a vapor phase containing CO2 with 5.31 mol % CH4. Experimental data (points) and CPA calculations (lines). The model was applied to correlate the phase equilibria and to predict the densities of binary mixtures. Using the binary parameters from the corresponding binary systems, the model was applied to predict the phase behavior of several ternary and multicomponent mixtures. Some results are shown in figures 1-2. The results reveal that


CPA is a versatile model that can capture the complicated phase behavior of such systems, while one of the best approaches is to model acid gases considering that they are not self-associating fluids and accounting for cross-associating interactions with water and alcohols. Often, equally good results are obtained by treating acid gases as self-associating fluids [2].

0 50 100 150 200 250 300 350 400 450

0.0

0.2

0.4

0.6

0.8

1.0

Den

sity

/ g

cm-3

Pressure / bar

323 K

Figure 2. Density of CO2 – water saturated phases. Experimental data for water rich phase (solid symbols), CO2 rich phase (open symbols) and CPA predictions (lines) References [1] G.M. Kontogeorgis, E.C. Voutsas, I.V. Yakoumis, D.P. Tassios, Ind. Eng. Chem. Res. (1996), 35, 4310-4318. [2] I. Tsivintzelis, G.M. Kontogeorgis, M.L. Michelsen, E.H. Stenby, AIChE J. (2010), 56, 2965-2982.


PI-19. Dynamic flow method to study the CO2 loading capacity of amino acid salt solutions

Lerche B.M.1, Stenby E.H.2, Thomsen K.1

1 - CERE (Center for Energy Resources Engineering) Department of Chemical and Biochemical Engineering, DTU (Technical University of Denmark) Søltofts plads building 229, 2800 Kgs.

Lyngby. DK 2 - CERE (Center for Energy Resources Engineering) Department of Chemistry, DTU (Technical University of Denmark) Søltofts plads building 229, 2800 Kgs. Lyngby. DK

[email protected]

Introduction Due to a number of advantages amino acid salt solutions have emerged as alternatives to the alkanolamine solvents for the chemical absorption of CO2 from flue gas. The use of amino acids in CO2 capture is a bio-mimetic process, as it is similar to CO2 binding by proteins in the blood, such as hemoglobin. Amino acid salt solutions have the same amine functionality as alkanolamines, and are thus expected to behave similar towards CO2 in flue gas. Despite rising interest, few studies have been performed so far on amino acids as CO2 absorbents. [1]

Studying the CO2 loading capacity of amino acid salt solutions For the purpose of studying the CO2 loading capacity of amino acid salt solutions, we have developed an experimental set-up (Figure 1) based on a dynamic analytical mode, with analysis of the effluent gas.

Figure 1: Experimental set-up to study the CO2 loading capacity of amino acid salt solutions.

The aim has been to mimic, the actual conditions for CO2 absorption from a coal fired power plant, as closely as possible. We describe the construction and validation of the


set-up. Validation data were produced using aqueous solutions of mono-ethanolamine (MEA), and compared to modelling data, as well as experimental data from literature. Following this validation, the CO2 loading capacity of aqueous solutions of the potassium salts of selected amino acids was examined. These experiments were performed at a partial pressure of CO2 close to 10 kPa, and a total pressure around 100 kPa, and a temperature close to 298 K.

References [1] Benedicte Mai Lerche, Erling H. Stenby and Kaj Thomsen. “CO2 Capture from Flue Gas using Amino Acid Salt Solutions”. Proceedings from Risoe International Energy Conference 2009.


PI-20. Densities, excess volumes, isobaric expansivities and isothermal compressibilities of the 1-butyl-3-

methylimidazolium methylsulfate + methanol system at temperatures (283.15 to 353.15) K and pressures from (0.1 to

35) MPa

Matkowska D., Hofman T.

Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology

[email protected]

During the past 10 years ionic liquids (ILs) have been recognized as novel solvents, which are liquids over a wide temperature range including room temperature. ILs are expected to reduce or eliminate the hazards associated with volatile organic solvents and have been applied in growing applications such as solvents for organic and catalytic reactions, new material productions, solvents for separation and extraction processes, novel electrolytes for electrochemical devices and process, enzyme catalysis/multiphase bioprocess operations, and so on. Obviously, understanding the physical-chemical properties of the ILs is critically important for these applications.

This contribution is a part of a systematic study of the volumetric properties of pure ionic liquids and their mixtures over a wide range of temperatures and pressures [1,2,3]. It reports data concerning pure 1-butyl-3-methylimidazolium methylsulfate ionic liquid – [C4mim][MeSO4] and its solution with methanol. The densities have been measured with an accuracy of ± 0.2 kg⋅m-3, over the temperature range (283.15 to 353.15) K and pressure range (0.1 to 35) MPa, using a vibrating tube Anton Paar DMA 512 P densimeter. Excess volumes have been derived directly from the experimental densities and isobaric expansivities, isothermal compressibilities and related excess properties have been calculated with the use of the correlation equation.

References [1] A. Gołdon, K. Dąbrowska, T. Hofman, J. Chem. Eng. Data, (2007), 52, 1830-1837. [2] T. Hofman, A. Gołdon, A.Nevines, T.M. Letcher J. Chem. Thermodyn., (2008), 40, 580-591. [3] D. Matkowska, T. Hofman, J. Chem. Eng. Data, (2010), 55, 685-693.


PI-21. Dilatational rheology of the adsorption films of complexes between globular proteins and ionic surfactants

Mikhailovskaya A.A.1, Lin S.-Y.2, Loglio G.3, Miller R.4

1 - St.Petersburg State University, Russia 2 - National Taiwan University of Science and Technology, Taiwan

3 - Universita degli Studi di Firenze, Italy 4 - MPI für Kolloid- und Grenzflächenforschung, Germany

[email protected]

Investigation of the protein denaturation at liquid-fluid interfaces is the main problem of modern structural biology. Proteins are also frequently applied as emulsifiers in various branches of industry. In spite of the special importance of surface properties of protein systems for numerous natural and industrial processes [1], unfolding of protein globules has been studied almost exclusively in bulk phases. The extent of the protein secondary and tertiary structure modification at the interface is now a subject of controversy. The lack of corresponding information is caused by a limited number of experimental methods applicable to the surface layer of complex liquids. There is almost no information on the surfactant impact on the structure of adsorbed films of globular proteins.

It has been shown recently, that one can successfully apply the methods of surface dilational rheology to study changes of the protein’s secondary and tertiary structure at the liquid-air interface. It is possible to observe a local maximum of the surface elasticity kinetic dependence of the mixed solution of bovine serum albumin (BSA) and guanidine hydrochloride (GuHCl) when the denaturant concentration approaches a critical value of about 0,65 М. This feature indicates the onset of protein unfolding in the surface layer. The disruption of tertiary and partially secondary structure of the protein leads to the increase of molecular flexibility and thereby to the formation of a distal region of the surface layer (the region of “loops” and “tails”). In this case, the relaxation of surface stresses can proceed at the expense of segment exchange between the distal and proximal regions of the surface layer resulting in a decrease of surface elasticity. The disruption of globular structure in the bulk phase occurs at higher concentrations of GuHCl (> 4М) indicating that the interface has a special influence on the protein denaturation.

Similar dependencies were observed in the case of mixed solutions of globular proteins (BSA and β-lactoglobulin) and a cationic surfactant (dodecyltrimethylammonium bromide). An increase of the surfactant concentration leads to the adsorption acceleration and changes of the shape of the surface elasticity kinetic curves. In the case of protein solutions containing an anionic surfactant (sodium dodecylsulfate) one can observe the local maximum only when the increase of the solutions ionic strength due to NaCl addition results in the shielding of electrostatic interactions in the system. One can


observe non-monotonous kinetic dependencies of the surface elasticity when the secondary structure in the solution bulk changes only slightly. This indicates a greater extent of the secondary structure disruption in the surface layer as compared with the bulk phase.

This work was financially supported by the Russian Foundation of Basic Research and National Science Counsel of Taiwan (joint project No. 09-03-92002-HHC_a and RFBR project 11-03-00801-а).

References 1. Maldonado-Valderrama J., Patino J.M.R., Curr. Opin. Colloid Interface Sci. 2010,15, 271. 2. Noskov B.A., Mikhailovskaya A.A., Lin S.-Y., Loglio G., Miller R., Langmuir 2010, 26, 17225.


PI-22. Physico-chemical Properties and Phase Behaviour of Different Piperidinium-based Ionic Liquids

Paduszyński K., Królikowska M., Domańska-Żelazna U.M.


[email protected]

The sufficient review of the existing literature of the 1-alkyl-1-methylppiperidinium-based ionic liquids has been presented. The phase diagrams for the binary systems of 1-butyl-1-methylpiperidinium thiocyanate [BMPIP][SCN] + an alcohol (1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, 1-dodecanol), or + water, or + aliphatic hydrocarbons (n-hexane, n-heptane, n-octane), or + cyclohexane, or, + cycloheptane, or + aromatic hydrocarbons (benzene, toluene, ethylbenzene) and for the binary systems of 1-ethyl-1-methylpiperidinium bis(trifluoromethyl)sulfonylimide [EMPIP][NTf2] + an alcohol (ethanol, 1-propanol, 1-butanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol), or + water have been determined at atmospheric pressure using a dynamic method. The influence of an alcohol chain length was discussed for these ionic liquids. A systematic decrease in the solubility was observed with an increase of the alkyl chain length of an alcohol. (Solid + liquid) phase equilibria with complete miscibility in the liquid phase region were observed for the systems involving water and the alcohols for the thiocyanate-based ionic liquid. Opposite, the bis(trifluoromethyl)sulfonylimide-based ionic liquid reveal the immiscibility gap in the liquid phase. The correlation of the experimental data has been carried out using the NRTL equation. The phase diagrams reported here have been compared to the systems published earlier with the 1-alkyl-1-methylpiperidinium-based ionic liquids. The influence of the cation and anion on the phase behaviour has been discussed. The basic thermal properties of pure ILs, i.e. melting temperature and the enthalpy of fusion, the solid-solid phase transition temperature and enthalpy have been measured using a differential scanning microcalorimetry technique.

References [1] U. Domańska, M. Królikowska, K. Paduszyński, Fluid Phase Equilib. 2011, DOI:10.1016/j.fluid.2010.12.008.


PI-23. The Hildebrand’s Solubility Parameters of Ionic Liquids

Marciniak A., Domańska-Żelazna U.M., Paduszyński K.


[email protected]

Since the ILs have a negligible vapor pressure, the inverse gas chromatography (IGC) is a suitable method for measuring thermodynamic properties of pure substances and their mixtures. From the retention data, the activity coefficients at infinite dilution, Flory-Huggins interaction parameters as well as the Hildebrand’s solubility parameters can be determined [1].

The Hildebrand’s solubility parameters have been calculated for 8 ionic liquids:

- 1-(3-hydroxypropyl)pyridinium trifluorotris(perfluoroethyl)phosphate, - 1-(3-hydroxypropyl)pyridinium bis(trifluoromethylsulfonyl)-amide, - 1-ethyl-3-methylimidazolium tetracyanoborate, - 1-decyl-3-methylimidazolium tetracyanoborate, - 1-butyl-1-methylpiperidinium thiocyanate, - 1-propyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)-amide, - 1-butyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)-amide, - N-octyl-isoquinolinium bis(trifluoromethylsulfonyl)-amide.

Retention data from the inverse gas chromatography measurements of the activity coefficients at infinite dilution were used for the calculation. From the solubility parameters, the standard enthalpies of vaporization of ionic liquids were estimated.

References [1] A. Marciniak, Int. J. Mol. Sci., (2010), 11, 1973-1990.


PI-24. Drugs solubility prediction using group contribution method

Pelczarska A.1, Domańska-Żelazna U.M.1,2, Ramjugernath D.2, Pobudkowska A.1

1 - Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology, ul. Noakowskiego 3, 00-664 Warsaw, Poland

2 - Thermodynamic Research Unit, School of Chemical Engineering, University of KwaZulu-Natal, Howard College Campus, King George V Avenue, Durban 4001, South Africa

[email protected]

Thermodynamic behaviour, including the solubility of solid drugs in liquid solvents, plays a pivotal role in designing of drug compounds as well as in the development and optimization of drug manufacturing processes. Particularly, drug design approaches based on combined chemistry and quantitative structure-activity relationships have led to potent new chemicals that tend to be more lipophilic and less water soluble. As the lipophilicity of a series of compounds decreases, so does their ability to cross biological membranes by passive diffusion increases. The membrane/water apparent partition coefficient, an indicator of lipophilicity, relates the latter internal gradient to the external bulk-water concentration difference between the two solutions separated by the membrane. The models used in the prediction of solubility of pharmaceuticals are important tools for early drug-designing processes.

Group contribution model, as UNIFAC, is used for calculations of activity coefficients in liquid phase based on molecular structure of solid [1]. In this work group contribution model, presented by Moller [2], was used. Predicted solubility for (solid + liquid) phase equilibria of 42 binary mixtures containing 16 different pharmaceuticals have been calculated in wide range of temperatures. Calculated data have been compared to experimental data published by us previously [3-6]. Additionally, the predictions recalculated with usage of one experimental point have been done and compared to experimental data, with very good results. References [1] A. Fredenslund, R.L. Russel, J.M. Prausnitz, AIChE J. 21 (1975) 1088-1099. [2] B. Moller, Activity of Complex Multifunctional Organic Compounds in Common Solvents, PhD Thesis, Chemical Engineering, University of KwaZulu-Natal (2009). [3] U. Domańska, A. Pobudkowska, A. Pelczarska, P. Gierycz, J. Phys. Chem. B 111 (2009) 8941-8947. [4] U. Domańska, A. Pobudkowska, A. Pelczarska, M. Winiarska-Tusznio, P. Gierycz, J. Chem. Thermodyn. 42 (2010) 1465-1472. [5] U. Domańska, A. Pobudkowska, A. Pelczarska, Ł. Żukowski, Int. J. Pharmaceut. 403 (2011) 115-122. [6] U. Domańska, A. Pobudkowska, A. Pelczarska, J. Phys. Chem. B (2011) in press.


PI-25. Solubility and Thermodynamic Properties of the Binary Systems Pharmaceutical + Water, or + Ethanol, or +

1-Octanol

Domańska-Żelazna U.M., Pobudkowska A., Pelczarska A.


[email protected]

Solubilities of many pharmaceuticals, were measured in range of temperature from (240 to 340) K in three important for drugs solvents: water, ethanol and 1-octanol at constant pH using the dynamic method and spectroscopic UV-Vis method. For example the derivatives of anthranilic acid having anti-inflammatory direction of action (niflumic acid, flufenamic acid, mefenamic acid and diclofenac sodium were mesured. Dissociation constants and corresponding pKa values of drugs were obtained with Bates-Schwarzenbach method using UV-Vis Perkin-Elmer Lambda 35 Spectrophotometer at temperature 298.15 K in the buffer solutions. The basic thermal properties of pure drugs i.e. fusion and glass-transition temperatures, as well as the enthalpy of fusion and the molar heat capacity at glass transition (at constant pressure) have been measured with differential scanning microcalorimetry technique (DSC). Molar volumes have been calculated with the Barton group contribution method. The experimental solubility data have been correlated by means of three commonly known GE equations: the Wilson, NRTL and UNIQUAC with the assumption that the systems studied here have revealed simple eutectic mixtures. The activity coefficients of pharmaceuticals at saturated solutions in each correlated binary mixture were calculated from the experimental data. Prediction of solubility in all solvents was made by the group contribution method UNIFAC Do (calculating the activity coefficients at infinite dilution) at a measured temperature range. Predicted solubilities of each system have been calculated with modified UNIFAC method, and compared with experimental points. Predictions included one experimental point in hole spectrum of solvent liquid phase, have been calculated and compared as well.


275

285

295

305

315

325

335

345

355

365

375

0 0,2 0,4 0,6

T/K

x1

290

300

310

320

0,E+00 3,E-06 6,E-06

Figure 1. Experimental and calculated SLE of flufenamic acid + solvent binary systems: , water; , ethanol; , 1-octanol. Solid lines have been designated by the NRTL equation. Dotted line represents ideal solubility. References

[1] U. Domańska, A. Pobudkowska, A. Pelczarska, P. Gierycz, J. Phys. Chem B 11 (2009) 8941-8947. [2] U. Domańska, A. Pobudkowska, A. Pelczarska, M. Winiarska-Tusznio, P. Gierycz, J. Chem Thermodyn. 42 (2010) 1465-1472. [3] U. Domańska, A. Pobudkowska, A. Pelczarska, A. Żukowski, Intern. J. Pharm. 403 (2011) 115-122.

NH

O OH F

FF


PI-26. Physicochemical Properties and Activity Coefficients at Infinite Dilution for Organic Solutes and Water in the

Tetracyanoborate-based Ionic Liquid

Domańska-Żelazna U.M., Marciniak A., Królikowska M.


[email protected]

The activity coefficients at infinite dilution, 13γ∞ and gas-liquid partition coefficients, KL

for 43 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones and water in two new ionic liquid named: 1-ethyl-3-methylimidazolium tetracyanoborate, [EMIM][TCB] and 1-decyl-3-methylimidazolium tetracyanoborate [DMIM][TCB] were determined by gas-liquid chromatography at wide range of temperatures. The partial molar excess Gibbs energies E,

1∆G ∞ , enthalpies E,

1∆H ∞ and entropies E,1∆S ∞ at infinite dilution were calculated from the experimental

13γ∞ values obtained over the temperature range. Additionally the densities for

investigated ionic liquids over the temperature range were determined. The selectivities for aliphatic/aromatic hydrocarbons separation problem were calculated from the experimental 13γ

∞ and compared to the literature values for different ionic liquids and NMP, or sulfolane. It was found that [EMIM][TCB] shows much higher selectivity for the separation of aliphatic hydrocarbons from aromatic hydrocarbons than [DMIM][TCB], NMP and Sulfolane.

References U. Domańska, A. Marciniak, J. Phys. Chem. B 114 (2010) 16542-16547.


PI-27. Thermodynamic studies on Ammonium and Phosphonium Ionic Liquids for the Separation of

Aliphatic/Alcohol Mixtures

Reddy P.1, Kaleng C.1, Tadie M.1, Deenadayalu N.2, Ramjugernath D.1

1 - Thermodynamics Research Unit, School of Chemical Engineering, Howard College Campus, University of KwaZulu-Natal, 4041, Durban, South Africa

2 - Department of Chemistry, Steve Biko Campus, Durban University of Technology, P.O. Box 1334, Durban, 4000, South Africa

[email protected]

Investigations of thermophysical and thermodynamic properties of ionic liquids (ILs) have largely been dominated by measurements on those containing an aromatic cation such as imidazolium, pyridinium and pyrrolidinium1,2. In particular, ammonium and phosphonium ILs have limited phase equilibrium or thermophysical data available. There are numerous separation challenges that are prevalent in industrial chemical streams such as aliphatic/aromatic, aliphatic/alcohol and alcohol/water mixtures. Studies thus far1,2 have shown that ammonium and phosphonium ionic liquids do not appear to be promising for aliphatic/aromatic separations. However, these types of ionic liquids have advantages in terms of cost of solvent production and availability of toxicological data over those with aromatic cations3,4. To properly assess the potential of these two classes of ionic liquids for industrial separation processes such as solvent extraction and extractive distillation for aliphatic/alcohol and alcohol/water separations, it is imperative that thermodynamic parameters for screening ammonium and phosphonium ILs be obtained.

Gas-liquid chromatography and ternary liquid-liquid equilibrium data allow for the reliable acquisition of thermodynamic data required for screening ionic liquids in separation processes5. Gas-liquid chromatography provides an expedient path for the measurement of activity coefficients at infinite dilution ( 13γ

∞ ) of solutes in an ionic liquid solvent. The 13γ

∞ values can be used to estimate the efficacy of the IL solvent to effect a specific separation.

Liquid-liquid equilibrium studies provide binodal curves and tie line data5, from which important conclusions about the separation efficiency of the solvent can be drawn. Ammoeng™ ILs are an interesting class of amphiphilic ILs for which only one phase equilibrium study has been conducted to date6. There have been no ternary liquid-liquid equilibrium studies that have been conducted on a phosphonium IL to date. Only one study has been performed on tributyl(methyl)phosphonium methylsulfate or [3C4C1P][MeSO4] by gas-liquid chromatography7 and the study contained no information on the separation of aliphatic/alcohol mixtures.


In this work, 13γ∞ values have been obtained for water and organic compounds (n-

alkanes, cycloalkanes, 1-alkenes, 1-alkynes, aromatics, alcohols and ketones) in the Ammoeng™ 100 ionic liquid at four different temperatures T = (308.15, 313.15, 323.15 and 333.15) K. The uncertainty in the measurement of the 13γ

∞ values is 5%. The results from this study have shown that Ammoeng™ 100 is superior to other ammonium ILs that have been studied thus far for the separation of n-hexane/methanol and n-heptane/ethanol mixtures. Ternary liquid-liquid equilibria have also been obtained by the cloud-point technique for the systems of [3C4C1P][MeSO4] + ethanol + an alkane (decane, dodecane or hexadecane) at T = 298.2 (± 0.1) K and atmospheric pressure, with an uncertainty in the measurement of the phase compositions of ± 0.005 mole fraction. The large immiscibility regions and solubility of the alcohol in the ionic liquid phase indicate that [3C4C1P][MeSO4] is suitable as a solvent for aliphatic/alcohol separations.

Future studies on separating alcohol/water mixtures and using different anion pairings with these two classes of ILs can provide greater insight with regards to fine-tuning or optimizing these structures for separating complex aqueous or organic mixtures.

References [1] A. Marciniak, Fluid Phase Equilibria, 294, (2010), 213-233. [2] G.W. Meindersma, A.R. Hansmeier, A.B. de Haan, Industrial and Engineering Chemistry Research, 49, (2010), 7530-7540. [3] B. Weyershausen, K. Lehmann, Green Chemistry, 7, (2005), 15-19. [4] T.P.T. Pham, C-H. Cho, Y-S. Yun, Water Research, 44, (2010), 352-372. [5] P. Reddy, T.M. Letcher, in: T.M. Letcher (Ed.), Thermodynamics, Solubility and Environmental Issues, Elsevier, Amsterdam, 2007, pp. 85-107. [6] A.B. Pereiro, A. Rodriguez, Journal of Chemical Thermodynamics, 41, (2009), 951-956. [7] T.M. Letcher, P. Reddy, Fluid Phase Equilibria, 260, (2007), 23-28.


PI-28. Topological analysis of phase diagrams of reactive systems: evaporation and membrane processes in comparison

Toikka A., Pulyalina A., Polotskaya G.

Dep. Chemical Thermodynamics & Kinetics, Faculty of Chemistry, Saint-Petersburg State University. Universitetskiy pr. 26, Peterhof, St. Petersburg 198504, Russia

[email protected]

Topological analysis of phase diagrams is the initial step in describing and study of mass-transfer processes and thermodynamic properties of complex multicomponent systems. Such analysis for evaporation (open evaporation, vapour–liquid phase transitions) can be made on the base both residue curve maps and diagrams of isotherms–isobars. Ternary and multicomponent vapour–liquid systems were considered in works of Gurikov, Serafimov, Zharov, Doherty and co-workers. The main characteristic of a residue curve map is a number and location of azeotropic points. In the case of the reactive systems one can distinguish additional singularities (reactive and isoaffinity lines, chemical equilibrium curve, etc.); special cases of reactive and kinetic azeotropes occur.

In our presentation we consider diagrams (residue curve maps) of evaporation and membrane processes in reactive systems in comparison. The pervaporation (PV) is the example of membrane process. The product of PV separation is a vapour phase; because of it the process is considered as evaporation through membrane. Open evaporation and evaporation through membrane have both some similar peculiarities (liquid–vapour transition) and significant differences. For example the vapour-liquid interface in PV system is membrane but the interface in vapour–liquid system could also be considered as a natural membrane. On the other hand due to the pressure gradient (the vacuum mode of PV) the PV system should be considered as nonequilibrium one and the capacities of the use of classical thermodynamic methods are limited. In the case of reacting systems the complexity of the analysis of PV process increase. Nevertheless thermodynamic methods combined with kinetic approach and nonequilibrium theory give opportunities for the analysis of such complex systems. For the small fluxes (usual for the PV) and fast reactions the feed solution can be considered as a system in a chemically equilibrium state. Accordingly the residue curve map of reactive PV process (similar to simple distillation of reactive mixtures) may be presented with the use of transformed composition variables (Zharov, 1970, Barbosa and Doherty, 1987). In the case of low reaction rate additional parameters similar to Damköhler number can be taken into account.

In the presentation some other aspects of topological and thermodynamic analysis of phase transitions in evaporation (simple distillation) and PV processes with its application to reactive systems are considered. Singularities of residue curve maps including vicinity of azeotropic points both for evaporation (vapour–liquid equilibrium)


and for PV followed by the general topological and thermodynamic analysis of phase diagrams of reactive systems are discussed in comparison. The special case of liquid phase splitting is considered for PV system. Residue curve map for PV in the system with limited miscibility include some special singular points, such as heterogeneous permazeotrope. Some examples will be given on the base of our and literature experimental data.

Acknowledgement This research was supported by Russian Foundation for Basic Research (grant 09-03-00812-a).


PI-29. Thermodynamic modeling of evaporation through membrane on the base of nonequilibrium thermodynamics

approach

Toikka A.1, Penkova A.1, Markelov D.2

1 - Dep. Chemical Thermodynamics & Kinetics, Faculty of Chemistry, Saint-Petersburg State University. Universitetskiy pr. 26, Peterhof, St. Petersburg 198504, Russia

2 - Dep. Statistical Physics, Faculty of Physics, Saint-Petersburg State University. Ulyanovskaya ul. 3, Peterhof, St. Petersburg 198504, Russia

[email protected]

The thermodynamic modeling of membrane processes is considered on the base of linear approach of nonequilibrium thermodynamics. The object is pervaporation process (PV), i.e. the case of evaporation through membrane, one of the main membrane processes with great advantages for the industrial applications. The pressure gradient in the vacuum PV (usual mode) determines the nonequilibrium run of the process. Accordingly the thermodynamic analysis of this membrane process should be considered on the base of nonequilibrium thermodynamics. Kedem (1986) was one of the first who introduce some elements of nonequilibrium thermodynamics in the theory of PV: the description of the coupling between fluxes was based on phenomenological laws and Onsager reciprocal relations. Nevertheless the development of the thermodynamic theory of PV was not intensive in regards to practical applications of thermodynamic approach. Our consideration of evaporation through membrane is based on the general equations of nonequilibrium thermodynamics. As usual we applied linear phenomenological laws that connect fluxes and thermodynamic forces. One of the problems had been the task of the identification of forces: according to classical approach it should be the gradients of chemical potentials (at constant temperature and pressure). For calculation of forces we had applied some assumptions which enable to estimate the force values from the experimental data on vapor – liquid equilibrium in feed mixture (Penkova, Markelov, Toikka, 2010). The values of kinetic coefficients (in our method – the ratio of kinetic coefficients) could be determined with the use of experimental data on PV for few compositions of feed mixture. Then the phenomenological equation with calculated coefficients could be applied for approximation of the experimental PV data or for modeling and calculation PV process in the wide diapason of feed composition (e.g. for the prediction of permeate composition). Few example of calculation will be given on the base of our and literature experimental data. The results of modeling and calculation of the parameters of PV process for some binary systems are in good agreement with experimental data. Acknowledgement This research was supported by Russian Foundation for Basic Research (grant 09-03-00812-a).


PI-30. Thermophysical Properties of 1-butyl-1-methylimidazolium tris(perfluoroalkyl)trifluorophosphate

[C4mim][FAP]

Ribeiro A.P.C.1,2, Langa E.1,2, Vieira S.I.C.1, Goodrich P.2, Hardacre C.2, Lourenço M.J.V.1, Nieto De Castro C.A.1

1 - Departamento de Química e Bioquímica and Centro de Ciências Moleculares e Materiais, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal 2 - The QUILL Centre/ School of Chemistry and Chemical Engineering, Queen's University

Belfast, Belfast BT9 5AG, U.K.

[email protected]

Tris(pentafluoroethyl)trifluorophosphate (FAP) ionic liquids exhibit excellent hydrolytic stability, low viscosity and high electrochemical and thermal stability. They are highly hydrophobic, but miscible with polar organic solvents. Due to his non coordinating anion it helps to stabilize carbo-cations.

Thermophysical properties of the ionic liquid (IL) 1-butyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate, [C4mim][FAP], namely thermal conductivity, heat capacity and refractive index, are reported for the first time, in temperature range from 293 K to 420 K, at atmospheric pressure. The thermal conductivity was determined using the transient hot-wire method, the heat capacity measurements obtained by DSC and the refractive index values measured with an Abbé refractometer.

Comparison of the behavior found for thermal conductivity and heat capacity with those of other IL’s was made to analyze the effect of the anion and the cation in the properties. It was found that the thermal conductivity decreases with the increasing size of the cation, although heat capacity increases. This behavior lead us to believe that different mechanisms are involved in the heat transfer and heat storage processes.

The thermal conductivity of 1-butyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate with multi walled carbon nanotubes (MWCNT) dispersed in it, an IoNanofluid, was also determined. The enhancement in thermal conductivity due to the presence of MWCNT varied between 4 and 9% in the temperature range studied. The behavior of this nanofluid, along with the specific behavior found in [C4mim][FAP], suggests the existence of nanocluster formation and preferred paths for heat transfer and storage, a fact that was reported for other systems containing ionic liquids and CNT in our previous studies [1,2].


a)

b) Figure 1. Comparison of thermal conductivity a), and heat capacity b) of ionic liquids with different anions.

References [1] C.A. Nieto de Castro, M.J.V. Lourenço, A.P.C. Ribeiro, E. Langa, S. I. C. Vieira, P. Goodrich, C. Hardacre, J. Chem. Eng. Data, (2010), 55 (2), 653–661 [2] A. P. C. Ribeiro, S. I. C. Vieira, J. M. França, C. S. Queirós, E. Langa, M. J. V. Lourenço, S. M. S. Murshed, C. A. Nieto de Castro, “Thermal Properties of Ionic Liquids and Ionanofluids”, in Ionic Liquids: Theory and Applications, Intech, 2010, ISBN 978-953-7616-X-X, in press.


PI-31. Molecular dynamics investigation of solvent diffusion outside and inside carbon nanotube

Shapovalova A.A., Burov S.V., Sizov V.V.

St.Petersburg State University, Chemistry Department

[email protected]

Investigation of adsorption and diffusion in carbon nanotubes is of the great interest due to unusual properties of molecular fluids in nanoscale heterogeneous systems. Establishing of regularities of diffusion behavior of molecular liquids in nanotubes plays important role, in particular for developing supercapacitors. We have done the molecular dynamics (MD) investigation of different diffusion regimes of solvents in model systems containing single wall carbon nanotubes (SWCNT) different diameters and solvent molecules (water, acetonitrile, methanol, dimethyl sulfoxide) at temperature 298K.

Firstly the bulk solvents were simulated to obtain diffusion coefficient of individual solvent, which later was used as a refer point. Then finite SWCNT with structure (11,11) or (15,15) was put into simulation cell of dimensions 10x10x5 nm filled by solvent which provides natural filling of SWCNT by solvent. Simulation time of such systems was 1 ns. From local density profiles the distance R from the surface of SWCNT, at which solvent density became equal to bulk solvent density, was calculated. This distance was used to construct simulation cell for modeling of infinite SWCNT: the length of cell was equal to length of SWCNT (4 nm) and width was fitted so that every distance between surface of SWCNT and edge of simulation cell was less than R. So we naturally divide solvent molecules to inside molecules and outside but nearby SWCNT surface. Simulation time of described systems was 5 ns.

Due to spatial anisotropy of investigated systems three types of diffusion coefficients were calculated: three-dimensional, along the axis of SWCNT and perpendicular to the axis. Solvent diffusion nearby outer surface has weak dependence on SWCNT diameter. At the same time it is anisotropic: the presence of nanotube impedes perpendicular to SWCNT axis diffusion. Parallel to axis diffusion nearby outer surface depends on nature of interactions between solvent molecules and SWCNT. Small increase of diffusion coefficient for water is observed due to weakening of hydrogen-bonds. In contrast diffusion coefficient of acetonitrile and especially dimethyl sulfoxide is decreased. Methanol has practically the same value as in bulk system. Diffusion coefficient anisotropy inside SWCNT is manifested extremely high especially for narrow nanotube (11,11). The values of parallel to SWCNT axis diffusion coefficients inside nanotube are found to be anomalously high. Visual analysis of motion trajectories showed that the reason of this anomalous diffusion is collective motion of molecules inside nanotube.

Several additional calculations were made to determine true diffusion coefficient inside SWCNT. First, the dependence of diffusion coefficient inside infinite nanotube on


periodically repeated section (i.e. on the size of simulation cell) was investigated. There is no reason to simulate outside solvent molecules at that stage so the length of simulation cell can be increased significantly: up to 100 nm and more. However even very long periodically repeated section of SWCNT can not guarantee the absence of collective motion of inside solvent.

Second stage was an investigation of solvent diffusion inside finite nanotube with open ends and the dependence of it on the length of SWCNT. In that case molecules can leave inside part of nanotube through open ends thus the necessity of simulation of additional outside solvent is appears, which increase the calculation complexity and decrease the maximum length of SWCNT. In addition special computer program is needed to calculate mean square displacement of solvent molecules inside SWCNT, which can take into account leaving and coming molecules “on the fly”. However due to finite volume of SWCNT the mean square displacement is also limited. At small nanotube length this will lead to the inaccurate determination of diffusion coefficient or even to impossibility of it, when finite size effects will occur even at ballistic regime of diffusion.

Third stage was an investigation of diffusion inside finite SWCNT with closed ends. In that case solvent molecules can not leave nanotube so there is no need to simulate outside solvent and the length of SWCNT can be increased significantly. At the same time finiteness of nanotube eliminates possible effects of collective motion. However the mobility of solvent molecules nearby closed ends can differ from the mobility in the centre of SWCNT. To eliminate the dependence of this fact on obtaining results the mean square displacement was calculated only in central part of nanotube using the program made for previous stage. Complex analysis of three ways of diffusion coefficient calculation allows us to obtain true values of solvent molecules mobility inside SWCNT.

This work was supported by RFBR grant # 09-03-01105-a


PI-32. Adsorption of CH4/CO2 mixtures in wet microporous carbons

Shapovalova A.A.1, Sizov V.V.1,2, Brodskaya E.N.1

1 - St. Petersburg State University, Department of Chemistry 2 - Stockholm University, Department of Materials and Environmental Chemistry

[email protected]

Adsorption of gas mixtures in porous carbonaceous materials is used in a variety of industrial and environmental applications, such as adsorptive gas separation or enhanced coalbed methane recovery (ECBM). In many of these applications the properties of adsorbents can be affected by the presence of water in the adsorbed mixtures or in the adsorbent itself. The effects of water on competitive adsorption of mixtures are still poorly understood since experimental studies often yield contradictory results. Computer simulations can provide insight into the molecular mechanisms underlying the phenomena observed in macroscopic experiments. In this contribution we report the results of Grand Canonical Monte Carlo (GCMC) simulations of adsorption of CH4/CO2 mixtures in microporous model carbons in the presence of pre-adsorbed water.

The intermolecular interactions between water and the components of the gas mixture were described by the combination of Lennard-Jones and Coulomb potentials. All-atom models OPLS-AA [1] and TraPPE [2] were chosen for CH4 and CO2 respectively. Three-site SPC/E [3] and four-site TIP4P/2005 [4] models were used for water. Carbonaceous adsorbents were modeled in the isolated slit pore approximation. The heterogeneous surfaces of the pore walls consisted of graphene-like fragments and oxygen-containing functional groups, and were modeled using the explicit-atom approach. The influence of the inner layers of carbonaceous adsorbent was described by the 10-4-3 potential [5].

The humidity of the adsorbent was set by placing the desired amount of water into the simulation basic cell. After preliminary NVT Monte Carlo simulations the formation of water clusters was observed, which was facilitated by the active sites on the surface of pore walls. The equilibrated configurations with pre-adsorbed water clusters were used as starting points for simulations of gas adsorption. GCMC simulations were carried out at 298 K and 318 K for different compositions of the gas phase, pressures up to 30 bar, pore widths from 0.8 nm to 2.0 nm, and different amounts of pre-adsorbed water.

In the GCMC simulations the number of H2O molecules remained constant since only displacement/rotation steps were allowed for water molecules. The number of gas molecules in the cell was varying due to insertion/deletion Monte Carlo steps, as determined by the chemical potentials of CH4 and CO2.


Non-monotonic dependence of adsorption capacity and selectivity on the amount of pre-adsorbed water was observed for some systems. This effect is interpreted as a result of competition between the decrease of accessible pore volume due to water pre-adsorption and the strengthening of electrostatic interactions with increasing water content. The difference in the interactions of water molecules with non-polar CH4 and more polar CO2 molecules is shown to have a pronounced effect on the composition of the adsorbed mixture. The influence of bulk gas pressure and composition on the adsorbent capacity, selectivity, and the local structure of the adsorbed mixture is also analyzed and discussed.

References [1] W.L.Jorgensen, D.S.Maxwell, J.Tirado-Rives. J.Amer.Chem.Soc. 118, 11225 (1996) [2] J.J.Potoff, J.I.Siepmann. AIChE J. 47, 1676 (2001) [3] H.J.C.Berendsen, J.R.Grigera, T.P.Straatsma. J.Phys.Chem. 91, 6269 (1987) [4] J.L.F.Abascal, C.Vega. J.Chem.Phys. 123, 234595 (2005) [5] W.A.Steele. Surf.Sci. 36, 317 (1973)


PI-33. Solubility of monosaccharides in ionic liquids - measuring and correlation

Carneiro A.P., Rodríguez O., Macedo E.A.

LSRE-Laboratory of Separation & Reaction Engineering, Associate Laboratory LSRE/LCM, Faculdade de Engenharia da Universidade do Porto, Portugal

[email protected]

Nowadays, ionic liquids (ILs) play an important role on green chemistry research. Together with supercritical fluids and ethylene glycols, they represent a huge potential in substituting common organic solvents in many applications. Usually, ionic liquids are defined as molten salts that exist as liquids at temperatures near to room temperature. This kind of salts exhibits exceptional properties such as negligible vapor pressure, high thermal stability, and since they are composed only by ions, there is a innumerous number of combinations to tune ionic liquid’s properties for each application1-4.

Currently, one of the major challenging tasks for many research groups is to investigate the way to produce chemicals through alternative pathways to petrochemical production. This is the goal of modern biorefineries that produce chemicals, energy and fuels from biomass feedstock. Biomass is composed mainly by cellulose, hemicellulose, lignin and starch. C5 and C6 sugars can be obtained from the acidic hydrolysis of cellulose and hemicellulose and they can be processed to produce compounds such as sorbitol, xylitol, succinic acid, aspartic acid and many other “building blocks” that are platforms for the production of innumerous value-added chemicals5-7. This biorefinery concept involves pre-treatment of biomass and many other adjuvant processes like reactions and extractions, and therefore, it needs adequate solvents to perform these operations.

Since the interest is on dissolving some of biomass compounds or extract them from aqueous streams, ILs can be designed to accomplish this goal. The capability of dissolving biomass and their derived compounds in ionic liquids has been demonstrated by several authors8-10. In order to design new processes involving ILs into biorefineries, solubility data of biomass compounds in them are needed. Nowadays these data are still scarce and it is almost inexistent over a wide range of temperature in order to correlate and model the results11,12.

To overcome this lack of data, the solubility of monosaccharides such as D-(+)-glucose, D-(-)-fructose, D-(+)-xylose and D-(+)-galactose in two ILs was measured in a temperature range from 288.15 K to 328.15 K. The ionic liquids selected for this work were the 1-ethyl-3-methylimidazolium ethylsulfate, [emim][EtSO4], which is a hydrophilic ionic liquid, and the methyltrioctylammonium chloride, Aliquat®336, hydrophobic.


The experimental technique used a combination of an isothermal method to attain the solid-liquid equilibrium and quantitative analysis by liquid chromatography (HPLC). The correlation of the solubility data was made through empirical equations and simple thermodynamic models such as NRTL. The thermodynamic functions of dissolution (Gibbs energy, enthalpy and entropy) were also determined.

Figure 1. Solubility data measured in this work.

References (1) Huddleston, J. G.; Willauer, H. D.; Swatloski, R. P.; Visser, A. E.; Rogers, R. D. Chemical Communications 1998, 1765. (2) Welton, T. Chem Rev 1999, 99, 2071. (3) Seddon, K. R. J Chem Technol Biot 1997, 68, 351. (4) Brennecke, J. F.; Maginn, E. J. AIChE Journal 2001, 47, 2384. (5) H. Clark, J.; E. I. Deswarte, F.; J. Farmer, T. Biofuels, Bioproducts and Biorefining 2009, 3, 72. (6) Werpy, T. A.; Holladay, J. E.; White, J. F. Top Value Added Chemicals From Biomass: I. Results of Screening for Potential Candidates from Sugars and Synthesis Gas, 2004. (7) Tan, S. S. Y.; MacFarlane, D. R. In Ionic Liquids 2009; Vol. 290, p 311. (8) Fukaya, Y.; Hayashi, K.; Wada, M.; Ohno, H. Green Chemistry 2008, 10, 44. (9) Fukaya, Y.; Sugimoto, A.; Ohno, H. Biomacromolecules 2006, 7, 3295. (10) Swatloski, R. P.; Spear, S. K.; Holbrey, J. D.; Rogers, R. D. Journal of the American Chemical Society 2002, 124, 4974. (11) Zakrzewska, M. E.; Bogel-Łukasik, E.; Bogel-Łukasik, R. Energy & Fuels 2010, 24, 737. (12) Rosatella, A. A.; Branco, L. C.; Afonso, C. A. M. Green Chemistry 2009, 11, 1406.


PI-34. Prediction of Gibbs Energy of Solvation and Corresponding Partition Coefficients from Molecular

Simulation

Garrido N.M.1,2, Jorge M.2, Queimada A.J.2, Macedo E.A.2, Economou I.G.1

1 - The Petroleum Institute, Department of Chemical Engineering, PO Box 2533, Abu Dhabi, United Arab Emirates

2 - LSRE Laboratory of Separation and Reaction Engineering, Associate Laboratory, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua

do Dr. Roberto Frias, 4200 - 465 Porto, Portugal

[email protected]

A methodology was proposed for the prediction of the Gibbs energy of solvation ( SolvG∆ ) based on Molecular Dynamics simulations [1]. In the present communication the prediction of SolvG∆ for four solutes (namely propane, benzene, ethanol and acetone) in several solvents of different polarities, including n-hexane, n-hexadecane, ethylbenzene, 1-octanol, acetone and water, represented by the TraPPE force field is shown. Excellent agreement with experimental data was obtained, with average deviations of 0.2, 1.1, 1.5 and 0.6 kJ/mol, for the four solutes respectively. Such results present a remarkable improvement in the prediction of this property when compared with other works [2].

In the second part of this work, partition coefficients for forty different systems containing solvents of different polarity (see Figure 1 for a complete list) were predicted. The a priori knowledge of partition coefficient values is of high importance in chemical and pharmaceutical separation processes design or as a measure of the increasingly important environmental fate. Here again, the agreement between experimental data and simulation predictions was excellent. An absolute average deviation of 0.15 log P units was obtained (Figure 1) which demonstrates that molecular simulation is a promising tool with strong physical basis to predict log P with competitive accuracy when compared to the popular statistics based methods, e.g., quantitative structure property relationships.


Figure 1. Overall comparison of experimental data against molecular dynamics predictions for the log P of different solutes in various solvent pairs.

References [1] N. M. Garrido, M. Jorge, A. J. Queimada, E. A. Macedo, I. G. Economou, (2011), submitted for publication. [2] D. P. Geerke, W. F. van Gunsteren, (2006) ChemPhysChem, 7, 671.


PI-35. Laccase partition in ATPS: finding some molecular descriptors

Silvério S.C.1,2, Rodríguez O.1, Teixeira J.A.2, Macedo E.A.1

1 - LSRE – Laboratory of Separation & Reaction Engineering, Associate Laboratory LSRE/LCM, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, s/n,

4200-465 Porto, Portugal 2 - IBB – Institute for Biotechnology and Bioengineering, Centre of Biological Engineering,

Universidade do Minho, Campus de Gualtar, 4710–057 Braga, Portugal

[email protected]

Aqueous Two-Phase Systems (ATPS) are known since 1896, when Beijerinck reported the formation of a biphasic system after mixing aqueous solutions of gelatine and agar or gelatine and starch. However, only in the 50’s, Albertsson showed the potential of these systems in the separation and purification of several biological constituents.1 In general, ATPS are obtained by mixing two aqueous solutions of different constituents that become immiscible above certain critical conditions, like temperature, concentration, etc. Both phases are composed mainly by water (>80%) and each one is enriched in a different component. ATPS formed by two polymers or a polymer and a salt represent the traditional systems. Nevertheless, other alternative biphasic systems can be obtained using surfactants, micellar compounds or ionic liquids.

ATPS are regarded as a useful extraction technique with a wide range of applications. Due to the high percentage of water present in their composition, ATPS can provide a gentle environment for the partitioning of sensitive biological materials, such as proteins, viruses, cells and cells’ organelles. These biphasic systems supply adequate conditions to the majority of biomolecules and allow their recovery in high purity level, without loss of biological activity. Furthermore, this kind of systems has low surface tension that permits biomolecule transfer through the interface with a minimum risk of structural changes.2,3 Other important characteristic of ATPS is the possibility to control the pH value of the medium, using buffer solutions when required by the biological constituents. During the last decades, ATPS were used in the recovery and purification process of biomolecules with either low or high commercial value.4 The recovery can occur from diverse biological media and the products are usually obtained with high yield (65-100%),5,6 which demonstrates the flexibility, robustness and potential of this extraction technique.6

In this work, partition of pure laccase enzyme in several ATPS was investigated. To obtain the partition coefficient (K) in each system, a total of six replicates of the same system were prepared, and then different amounts of laccase were added to each one. All K values determined correspond to the slope of the straight line obtained when laccase concentration in the top phase was plotted against laccase concentration in the bottom phase, for the six replicates.7


With the aim to describe and understand laccase partitioning in the several ATPS used in this work, some modeling studies were carried out using the solvatochromic solvent parameters8-10 and the free energy of transfer of a methylene group between the co-existing phases (∆G(CH2))3,11 as molecular descriptors. The solvatochromic parameters included solvent polarity/polarizability (π*), solvent hydrogen-bond donor acidity (α), and solvent hydrogen-bond acceptor basicity (β) of the aqueous media present in each phase. The partition coefficient of laccase was described by a linear equation containing both the solvatochromic solvent parameters and ∆G(CH2) contribution obtained by multiple linear regression.

References

(1) Albertsson P.A., Partition of Cell Particles and Macromolecules 1986, 3rd edition, New York. (2) Silva L.H.M. Química Nova 2006 29, 1345. (3) Zaslavsky B.Y., Aqueous Two-Phase Partitioning: Physical Chemistry and Bioanalytical Applications 1994, Marcel Dekker, New York. (4) Benavides J.; Rito-Palomares M. Journal of Chemical Technology and Biotechnology 2008, 83, 133. (5) Cisneros M.; Benavides J.; Brenes C.H.; Rito-Palomares M. Journal of Chromatography B 2004, 907, 105. (6) Rito-Palomares M. Journal of Chromatography B 2004, 807, 3. (7) Silvério S.C.; Madeira P.P.; Rodríguez O.; Teixeira J.A.; Macedo E.A. Journal of Chemical Engineering Data 2008, 53, 1622. (8) Kamlet M.J.; Taft R.W. Journal of the American Chemical Society 1976, 98(2), 377. (9) Kamlet M.J.; Taft R.W. Journal of the American Chemical Society 1976, 98(10), 2886. (10) Kamlet M.J.; Abboud J.L.M.; Taft R.W. Journal of the American Chemical Society 1977, 99(18), 6027. (11) Silvério S.C.; Rodríguez O.; Teixeira J.A.; Macedo E.A. Journal of Chemical Thermodynamics 2010, 42, 1063.


PI-36. Study of the influence of anion on thermal analysis of imidazolium-based ionic liquids

Calvar N.1, Gómez E.2, Domínguez A.2, Macedo E.A.1

1 - University of Porto, Portugal 2 - University of Vigo, Spain

[email protected]

Introduction Ionic liquids (ILs) have been proposed as alternative environmental friendly substitutes to the traditional organic solvents used in the chemical industry. Understanding basic thermophysical properties of ILs is vital for design and evaluation. For instance, thermal properties are needed to set the feasible temperature operating range for a particular fluid and heat capacities are needed to estimate heating and cooling requirements as well as heat-storage capacity. In this work, melting (Tm), glass (Tg), cold crystallization (Tcc) and freezing (Tf) temperatures and heat capacities (Cp) are presented as function of temperature for three imidazolium-based ILs. The ionic liquids investigated here are: 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([HMim][NTf2]), 1-hexyl-3-methylimidazolium dicyanamide ([HMim][(N(CN)2] and 1-hexyl-3-methylimidazolium trifluoromethanesulfonate ([HMim][TFO]). The aim of this work is to study the influence of the anion on the thermal properties. Experimental The ILs used in this study were supplied by IoLiTec with mass fraction purities > 0.98. Their maximum water mass fraction was 500 ppm. They were subjected to vacuum (P = 0.2 Pa) at moderate temperature (T = 70ºC) for at least 48 h. Measurements of phase transition temperatures were performed using a Mettler-Toledo differential scanning calorimeter (DSC), model DSC822e, together with Mettler-Toledo STARe software version 9.3. The instrument was calibrated for temperature and heat flow with zinc and indium reference samples provided by Mettler-Toledo. The presence of volatiles affects the glass transition and melting temperatures.1 Therefore, the sample was dried in situ on the DSC by holding it at T = 110ºC for 30 minutes. This process was repeated until the weight of the sample remained constant. Aluminium pans of 40 µL and 100 µL with a pinhole at the top hermetically sealed were used for thermal analysis and Cp determination, respectively. The sample pan and blank (an empty pan) were placed on separated raised platforms within the furnace and they were exposed to a flowing N2 atmosphere. Measurements for thermal analysis were performed by cooling the samples from 140ºC to -120ºC followed by heating from -120ºC to 140ºC. The rate of cooling and heating depend on the behavior of the studied IL. The heat capacities of the compounds were determined using the sapphire method. Measurements for Cp were carried out by


heating the samples from 0ºC to 90ºC, except for [HMim][TFO], where the starting temperature was 25ºC. The rate for the Cp measurements was 20ºC·min-1. Results and discussion The melting and freezing temperatures are taken to be the onset of an endothermic peak on heating and the onset of the exothermic peak on cooling, respectively. The glass transition temperature is the midpoint of a small heat capacity change on heating from amorphous glass state to a liquid state and the cold crystallization temperature is defined as the onset of as exothermic peak on heating from a subcooled liquid state to a crystalline solid state. The obtained results are presented in Figures 1-3. As it is plotted, all the studied ILs show a liquid subcooling to a glass state, however the IL with NTf2

- anion at temperatures higher than Tg also presents cold crystallization upon heating, and if the sample is heated further, it melts at Tm. Regarding [HMim][TFO], it has a distinct freezing point on cooling and a distinct melting point on heating. The heat capacities of the three ILs are reported in Table 1. In this table, significant changes can be observed in the heat capacity as a function of the anion, demonstrating that the Cp increases with the molecular weight of the anion.

mW

-40

-30

-20

-10

0

°C-120 -100 -80 -60 -40 -20 0 20 40 60 80

^ e x o

ST AR e SW 9 . 3 0La b : M ET T LER Figure 1: DSC scan for [HMim][N(CN)2]

Figure 2: DSC scan for [HMim][NTf2]

mW

-40

-20

0

20

40

60

80

°C-120 -100 -80 -60 -40 -20 0 20 40 60 80 100

^ e x o

ST AR e SW 9 . 3 0La b : M ET T LER

Compound Cp (25 ºC) /

J·mol-1·K-1 Cp (35 ºC) / J·mol-1·K-1

[HMim][NTf2] 579 608 [HMim][N(CN)2] 415 432 [HMim][TFO] − 417 Table 1: Heat Capacities of studied ILs

References [1] C.P. Fredlake, J.M. Crosthwaite, D.G. Hert, S.N.V.K. Aki and J.F. Brennecke, J. Chem. Eng. Data, (2004), 49, 954-964.

mW

-6

-5

-4

-3

-2

-1

0

1

2

°C-140 -120 -100 -80 -60 -40 -20 0 20 40 60 80 100 120 140

^ e x o

ST AR e SW 9 . 3 0La b : M ET T LER


PI-37. Measurement and modeling of vapor pressures and osmotic coefficients of binary mixtures 1-propanol +

CnMimNTf2 (n=2,3,4,6) at T = 323.15 K

Gómez E.1, Calvar N.2, González E.J.2, Domínguez A.1, Macedo E.A.2

1 - University of Vigo, Spain 2 - University of Porto, Portugal

[email protected]

Introduction The increasing presence of ionic liquids (ILs) in different processes requires a deeper knowledge about the nonideality of these mixtures, especially about their thermodynamic behavior. The osmotic and activity coefficients are also of great interest to evaluate the capabilities of usual thermodynamic tools. The vapor pressure osmometry (VPO) is a technique that allows obtaining very reliable experimental data using small amounts of sample. In addition, this technique is less time-consuming than other techniques used for vapor-liquid equilibria. In this work, osmotic and activity coefficients and vapor pressures of binary systems containing the primary alcohol 1-propanol and imidazolium-based ionic liquids with the anion bis(trifluoromethylsulfonyl)imide, CnMimNTf2 with n = 2, 3, 4, 6, have been determined at T = 323.15 K using the vapor pressure osmometry technique. The extended Pitzer model modified by Archer [1,2], and the modified NRTL (MNRTL) model [3] represent the experimental data satisfactorily.

Experimental The alcohol used in this work was purchased from Sigma-Aldrich, with a mass fraction purity > 0.999. The maximum water mass fraction was 4·10-6. The ionic liquids 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C2MimNTf2), 1-methyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide (C3MimNTf2), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C4MimNTf2) and 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C6MimNTf2), were supplied by IoLiTec, with mass fraction purities > 0.99. Ionic liquids were subjected to vacuum (p = 0.2 Pa) at moderate temperature (T = 343 K) for at least 48 h prior to their use. The mass fractions of water were determined using a 756 Karl Fisher coulometer, and they were less than 2·10-4. The vapor pressure osmometry measurements were performed with a Knauer K-7000 vapor pressure osmometer, with a temperature control of ± 0.01 K.

Results and Discussion From the measured quantity ∆R, the osmotic coefficients, φ, as a function of molality, m, can be calculated using the following relation,


m / mol·kg-1

0 1 2 3 4

φ

0.0

0.2

0.4

0.6

0.8

1.0

ν φ m = k ∆R (1) where ν is the number of ions into which the electrolyte dissociates, which in the case of the studied ionic liquid is 2, and k is the calibration factor. From the obtained osmotic coefficients (equation 1), the activity coefficients, and from them the vapor pressures, can be calculated using the following equations: φ = -ln as / ν m Ms (2) ln as = ln (p/p*) + (Bs-Vs*) (p-p*) / RT (3) where as is the activity of the solvent, Ms is the molecular weight of the solvent, T is the absolute temperature, R is the universal gas constant, p is the vapor pressure of the solution, and p* is the vapor pressure of the pure solvent, estimated with the Antoine equation. Bs and Vs* are the second virial coefficient and molar volume of the pure solvent, respectively. Vapor pressure depressions were calculated for the four binary systems: ∆p = p* – p (4) and they were fitted to a polynomial of the third degree. As can be observed from Figure 1, the osmotic coefficients and vapor pressure depressions increase as the alkyl chain of the cation of CnMimNTf2 increases. The ion-interaction model of Extended Pitzer model of Archer, and the local composition model MNRTL have been successfully used to correlate the experimental data, obtaining standard deviations lower than 0.023 and 0.032, respectively. a) b) Figure 1. a) Osmotic coefficients, φ1, and b) vapor pressure depression, ∆p, plotted against molality for the studied binary mixtures () 1-propanol + C2MimNTf2, (∆) 1-propanol + C3MimNTf2, () 1-propanol + C4MimNTf2, and (∇) 1-propanol + C6MimNTf2, at T = 323.15 K. Solid line (): extended Pitzer model of Archer. References [1] D.G. Archer, J. Phys. Chem. Ref. Data, (1991), 20, 509-555. [2] D.G. Archer, J. Phys. Chem. Ref. Data, (1992), 21, 793-829. [3] A. Jaretun and G. Aly, Fluid Phase Equilib. (1999), 163, 175-193.

m / mol·kg-1

0 1 2 3 4

∆ p /

kPa

0.0

0.2

0.4

0.6

0.8

1.0

1.2


PI-38. Measurements and Modelling of the Phase Equilibria of Ionic Liquids and Supercritical Carbon Dioxide

Manic M.S.1, Queimada A.J.2, Macedo E.A.2, Ponte M.N.1, Najdanovic-Visak V.1

1 - REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Quinta da Torre, 2829-516 Caparica, Portugal

2 - LSRE/LCM - Laboratory of Separation and Reaction Engineering, Faculdade de Engenharia, Universidade do Porto, Rua Dr.Roberto Frias, 4200-465, Porto, Portugal

[email protected]

Ionic liquids (ILs) – carbon dioxide (CO2) systems are widely studied nowadays, due to the high solubility of CO2 in ILs and the possibility to develop a variety of application of the ILs-CO2 system in different processes such as CO2 capture, separation of gases, purification of high value products or homogeneous catalyzed reactions [1]. Therefore, understanding the vapor-liquid equilibrium of ionic liquids and carbon dioxide is required. Although the solubility of CO2 in imidazolium based ionic liquids has been measured in large ranges of temperature (283 – 460 K) and pressure (up to74 MPa) [2], there is a lack of information for ionic liquids based on other different cations (ammonium, pyrrolidinium or phosphonium).

In this work the solubility data of CO2 in eight different ILs were measured in the pressure range of (8 – 20) MPa and at two temperatures, 313 K and 323 K. The gas solubility was determined at each fixed temperature and pressure. In order to discuss the influence of the cation, ILs based on bis(trifluoromethylsulfonyl)imide [NTf2]- anion were chosen. They were coupled with 1-butyl-3-methylimidazolium, [C4mim]+, 1-decyl-3-methylimidazolium, [C10mim]+, 1-butyl-1-methylpyrrolidinium, [bmpyr]+, butyltrimethylammonium, [N4111]+, methyltrioctylammonium, [N1888]+ and trihexyltetradecylphosphonium, [P66614]+ cation. The phosphonium based cation was combined with more two anions namely bromide, [Br]- and chloride, [Cl]-, giving an opportunity to further discuss the influence of the anion as well.

Despite the fact that experimental data already provides some information about the systems and helps to understand their behavior, development of prediction tools are very important due to immense number of potential applications of ionic liquid systems. The solubility data obtained in this work were used to evaluate the application of the Cubic Plus Association equation of state (CPA EoS) to estimate the behavior of the ILs-CO2 systems. A systematic study about how to obtain the pure component parameters and the effect of considering or not both CO2 and ionic liquids as associating components was performed.


Acknowledgment Marina Manic thanks Fundação para a Ciência e Tecnologia – Portugal for the doctoral fellowships SFRH/BD/45323/2008.

References [1] L.A. Blanchard, D. Hancu, E.J. Beckman, J.F. Brennecke, Nautre 1999, 399, 28-29;

L.A. Blanchard, J.F. Brennecke, Ind. Eng. Chem. Res. 2001, 40, 287-292; L.A. Blanchard, Z. Gu, J.F. Brennecke, J. Phys. Chem. B 2001, 105, 2437-2444; D.J. Cole-Hamilton, Science 2003, 299, 1702-1706; S. Raeissi, C.J. Peters, Green Chem. 2009, 11, 185-192; B.E. Gurkan, J.C. de la Fuente, E.M. Mindrup, L.E. Ficke, B.F. Goodrich, E.A. Price, W.F. Schneider, J.F. Brennecke, J. Am. Chem. Soc. 2010, 132, 2116-2117.

[2] S.N.V.K. Aki, B.R. Mellein, E.M. Saurer, J.F. Brennecke, J. Phys. Chem. B 2004 108, 20355-20365; D.-J. Oh, Korean J. Chem. Eng. 2006, 23, 800-805; B.C.Lee, S.L. Outcalt, J. Chem. Eng. Data 2006, 51, 892-897; E.-K. Shin, B.-C. Lee, J.S.Lim J. Supercr. Fluids 2008, 45, 282-292; W. Ren, B. Sensenich, A.M. Scurto, J. Chem. Thermodynamics 2010, 42, 305-311; S. Raeissi, C.J. Peters, J. Chem. Eng. Data 2009, 54, 382-386; P.J. Carvalho, V.H. Alvarez, I.M. Marrucho, M. Aznar, J.A.P. Coutinho, J. Supercr. Fluids 2009, 50, 105-111.


PI-39. Surface tensions of esters and biodiesels from a combination of the gradient theory with the CPA EoS

Oliveira M.B.1, Coutinho J.A.P.2, Queimada A.J.1

1 - LSRE - Laboratory of Separation and Reaction Engineering, Faculdade de Engenharia, Universidade do Porto, Rua do Doutor Roberto Frias, 4200 - 465 Porto, Portugal

2 - CICECO, Chemistry Department, University of Aveiro, 3810-193 Aveiro, Portugal

[email protected]

Ester compounds are widely used in applications such as solvents, plasticizers, polymers, lubricants, cosmetics, medicinals, agrochemicals, soaps and other surface active agents, to mention a few. In many of these applications the simultaneous knowledge of the phase behavior and interfacial properties is an advantage for designing better products and improved processes.

The van der Waals density gradient theory is an interesting theory providing such information. In this work it is applied for the first time to compute the surface tension of esters in a broad temperature range. A total of 37 ester compounds were evaluated, including formates, acetates, methyl, ethyl, propyl, butyl and unsaturated methyl esters.

For calculating the Helmholtz energy density and the bulk properties, the Cubic-Plus-Association equation of state was used. It is demonstrated that ester surface tensions can be estimated within 1.5% deviation to the experimental data using a simple correlation for the temperature dependence of the gradient theory influence parameter (Figure 1). Whenever the parameters for the linear temperature dependence of the influence parameter are considered to be constant only slightly higher deviations, below 5 %, were obtained.

The predictive ability of the proposed methodology was also tested when successfully predicting new experimental data on the temperature dependence of surface tensions of several biodiesels and their mixtures, measured by the research group.


Figure 1. Esters surface tensions. Experimental ( , methyl propanoate; ∆, nonyl formate; , methyl decanoate) and gradient theory results using a linear temperature dependency for the influence parameter (–). References [1] M.B. Oliveira, J.A.P. Coutinho, A.J. Queimada, (2011), Accepted for publication in Fluid Phase Equilibria.


PI-40. Modeling phase equilibria relevant to biodiesel production: A comparison of gE models, cubic EoS, EoS – gE

and association EoS

Oliveira M.B.1, Ribeiro V.2, Queimada A.J.1, Coutinho J.A.P.2

1 - LSRE - Laboratory of Separation and Reaction Engineering, Faculdade de Engenharia, Universidade do Porto, Rua do Doutor Roberto Frias, 4200 - 465 Porto, Portugal

2 - CICECO, Chemistry Department, University of Aveiro, 3810-193 Aveiro, Portugal

[email protected]

In this work, we evaluated the performance of commonly used excess Gibbs energy (gE) models, cubic equations of state (EoS), equations of state with EoS – gE mixing rules and association equation of state models in describing systems of relevance for biodiesel production.

The models used in this study are the UNIFAC, the Soave-Redlich-Kwong (SRK) EoS, the SRK-MHV2, the Peng-Robinson (PR) EoS using the MHV2 mixing rule, the predictive Soave-Redlich-Kwong (PSRK) EoS and the cubic-plus-association (CPA) EoS.

Results for the LLE and SLE of 6 water + fatty acid systems, the water solubility in 11 fatty acid methyl esters and 6 biodiesels, the VLE of 5 glycerol + alcohol and glycerol + water systems, the VLE of 7 ester + methanol and 6 ester + ethanol systems and the LLE of several multicomponent mixtures containing alcohols, glycerol, water and fatty acid esters, in the temperature range of operation of the transesterification and separation units in biodiesel plants, were evaluated considering models’ applicability and accuracy.

This work conclusively shows that the CPA EoS, through its association term that explicitly takes into consideration the association interactions, is the most adequate, consistent and reliable model to describe the phase equilibria in the biodiesel production related binary and multicomponent systems, as depicted as examples in Figures 1 and 2.

Its predictive character, flexibility, simplicity and accuracy are self evident from the results reported.


References [1] M.B. Oliveira, V. Ribeiro, A.J. Queimada, J.A.P. Coutinho, Industrial & Engineering Chemistry Research (2011), in press.

Figure 2. Water solubility in ethyl decanoate, experimental and model results.

Figure 1. VLE for the glycerol + 1-propanol system, experimental and model results.


PI-41. Experimental Measurements and Modelling of CO2 Solubility in Castor, Sunflower and Rapeseed Oils

Regueira T.1, Carvalho P.J.2, Oliveira M.B.2, Lugo L.1,3, Coutinho J.A.P.2, Fernández J.1

1 - Laboratorio de Propiedades Termofísicas, Departamento de Física Aplicada, Universidade de Santiago de Compostela, E1782 Santiago de Compostela, Spain

2 - CICECO, Departamento de Química, Universidade de Aveiro, 3810-193 Aveiro, Portugal 3 - Departamento Física Aplicada, Edificio de Ciencias Experimentales, Universidad de Vigo,

E-36310 Vigo, Spain

[email protected]

The environmental drive for the use of rapidly biodegradable oils has been a gradual process in Europe and niche markets have risen where mineral oils have been banned by legislation. Vegetable oils are an obvious choice. Vegetable oils can offer an optimum solution when the systems work at moderate temperatures, particularly in total-loss systems (drilling muds, chain-saw bar oils and outboard engines) and partial-loss systems (hydraulic oils and greases). With the aid of selective plant breeding, more thermal and oxidative stable vegetable oils are available. The commercial use of a vegetable-oil based systems would represent a significant environmental improvement in areas where hydrocarbons are still employed1.

Back in 2008 the European Commission has embraced a sustainable industrial policy, as part of a broader action plan on sustainable consumption and production, with the adoption of the EU Ecolabel. The Eco-label, given to products that have the potential to reduce certain negative environmental impacts, is divided in categories in which ‘lubricants’ stands as one and comprises, up to now, hydraulic oils, greases, chainsaw oils, two stroke engine oils, concrete release agents and other total loss lubricants2.

Vegetable oils usage as lubricants is environmentally preferred to petroleum-based oils, not only due to their renewable raw materials source but also to their biodegradability and non-toxicity3, 4. Other advantages include very low volatility, due to the high molecular weight of the triglyceride molecule, and excellent temperature-viscosity properties. Their polar ester groups are able to adhere to metal surfaces, and therefore, possess good lubricity. In addition, vegetable oils have high solubilising power for polar contaminants and additive molecules5. However there are concerns about their oxidative stability and low-temperature performance. Nonetheless, improvements in oxidative stability can be made through chemical or genetic modifications6.

Two stroke engines are mostly used when high specific power, low weight and low price are key parameters. Almost all these engines use total-loss lubrication where a large part of the lubricant is burnt in the combustion process but about one quarter is exhausted as unburned oil mist. Thus, there is a demand for environmentally compatible lubricants. The knowledge of the solubility of gases, like CO2, in lubricants used on two


stroke engines is one of the important parameters on the development and vegetable oils formulation.

In this work we have performed solubility measurements of CO2 in three vegetable oils susceptible of being used as lubricant base oils: castor, high oleic sunflower and rapeseed oil. Measurements were performed in a high pressure equilibrium cell, based on a cell designed by Daridon et al.7, using the synthetic method. Solubility was measured for mole fractions ranging from 0.15 to 0.93 from 263.15 K to 298.15 K and pressures up to 75 MPa. The CO2 solubility is similar in high oleic sunflower oil and in rapeseed oil but lower than in castor oil. Typically, the CO2 + oil phase diagram presents a decrease on the solubility as the gas composition and the system temperature increases. Here, a crossover, where the solubility starts to increase as the composition and temperature increases, is reported.

The experimental solubility data were successfully modelled with the Cubic-Plus-Association equation of state (CPA EoS). Two different approaches were considered for computing the oil CPA pure compound parameters, either trough critical properties or vapor pressure and liquid density data. As the model prediction performance depends on the CPA pure compound parameters, the best set of oil parameters and the way to determine them, were selected based on their suitability for modelling the new experimental phase equilibria here presented.

Acknowledgements We are very grateful to Verkol Lubricantes and Instituto de la Grasa (CSIC, Seville) for providing us the oil samples and the analysis of its fatty acid composition. This work was carried out within the framework of the (PSE-320100-2006-1, PSE-420000-2008-4) project financed by Spanish Science and Innovation Ministry and the EU FEDER program. L. L. acknowledges the financial support from the Ramon y Cajal Program. T.R. acknowledges financial support provided by the FPU program (Ministerio de Educación, Spain). The authors are thankful for financial support from Fundação para a Ciência e a Tecnologia through Pedro J. Carvalho Ph.D. grant (SFRH/BD/41562/2007).

References 1. P. Miles, J. Synth. Lubr., 1998, 15, 43-52. 2. Official Journal of the European Union, 2005, L 118/ 126-134. 3. N. S. Battersby, S. E. Pack and R. J. Watkinson, Chemosphere, 1992, 24, 1989-2000. 4. T. Regueira, L. Lugo, O. Fandiño, E. R. López and J. Fernández, Green Chem., 2011, Submitted. 5. S. Z. Erhan, B. K. Sharma and J. M. Perez, Industrial Crops and Products, 2006, 24, 292-299. 6. W. Castro, J. M. Perez, S. Z. Erhan and F. Caputo, JAOCS, 2006, 83, 47–52. 7. S. Vitu, J. N. Jaubert, J. Pauly, J. L. Daridon and D. Barth, J. Chem. Eng. Data 2007, 52, 1851-1855.


PI-42. Viscosity behavior of 1-ethyl-3-methylimidazolium ethylsulfate and 1-(2-methoxyethyl)-1-methyl-pyrrolidinium

bis(trifloromethylsulfonyl)imide at high pressures

Gaciño F.M., Paredes X., Comuñas M.J.P., Fernández J.

Laboratorio de Propiedades Termofisicas, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela, SPAIN

[email protected]

Ionic liquids (ILs) have a potential use in a wide range of applications due to their properties: negligible vapor pressure, low melting point, good thermal stability, fire resistance and tuneability. Among their applications, it is worth pointing out their use as base oils or lubricant additives [1,2]. To develop this new kind of base oils, physical properties that affect lubrication, such as viscosity and its dependence with temperature and pressure, should be reliably determined. Viscosities of ILs have been reported at atmospheric pressure but at high pressures are rather scarce. Harris et al. [3,4] measured the viscosities of several imidazolium ILs from 273.15 to 353.15 K and up to 200 MPa with a falling body viscometer. Tomida et al. [5] studied the viscosity of 1-butyl-3-methylimidazolium ILs from 293.15 to 353.15 K and up to 20 MPa by using a rolling body apparatus. Ahosseini and Scurto [6] published also viscosities of imidazolium-based ILs up to 126 MPa. In this work we focus our attention on the viscosity behavior at high pressure of 1-ethyl-3-methylimidazolium ethylsulfate and 1-(2-methoxyethyl)-1-methyl-pyrrolidinium bis(trifloromethylsulfo-nyl)imide. We have not found any previous viscosity data for these fluids at high pressure. The IL samples, provided by Merck with purity > 98%, were treated by vacuum evaporation to remove the residual volatile impurities. Their water content was determined by Karl Fischer titration. The measurements at high pressure have been performed with a new falling body viscometer designed at our laboratory to study liquids at pressures up to 150 MPa. This device is similar to that designed by Daugé et al. [7]. Figure 1 is a general view of the equipment. The measuring cell is made up of a cylindrical tube which contains another inner cylindrical tube. The sample is filled in both tubes to avoid any deformation of the inner tube itself. A cylindrical sinker with a hemispherical end falls vertically through the sample. Four electrical coils are fitted on the outer tube detecting the passage of the sinker through a variation of the magnetic flux. Another cylinder concentric with the measuring cell containing a heat-carrying liquid is connected to a thermostatic bath. The viscosity is a function of the time that takes the sinker to fall between two non-consecutive coils, of the density difference between the sinker and the fluid, and of the apparatus parameters. The equipment has been calibrated by using bis(2-ethylhexyl)phthalate from 313.15 to 363.15 K and up to 150 MPa. The accuracy of the viscometer was verified by comparing experimental results of squalane and diisodecyl phthalate with literature data, finding average absolute deviations lower than 3.5% and 5%, respectively. We have also used a viscometer Anton Paar Stabinger SVM3000 to measure the viscosity at 0.1 MPa from 253.15 to 373.15 K obtaining that the


experimental viscosities range from 7.3 to 620.3 mPa·s for 1-(2-methoxyethyl)-1-methyl-pyrrolidinium bis(trifloromethylsulfonyl)imide and from 9.5 to 3146.4 mPa·s for 1-ethyl-3-methylimidazolium ethylsulfate. The experimental viscosity data has been correlated as function of temperature and pressure with a modified VFT equation [8].

Figure 1. General view of the equipment Authors acknowledge Dr. Uerdingen from Merck for his advice and the samples provided. This work was supported by Spanish Ministry of Science and Innovation and EU FEDER Program through CTQ2008-06498-C02-01 project. References [1] I. Minami, Molecules, 14 (2009) 2286-2305. [2] A.S. Pensado; M.J.P. Comuñas, J. Fernández, Tribol. Lett. 31 (2008) 107. [3] K.R. Harris, M. Kanakubo, L.A. Woolf, J. Chem. Eng. Data 51 (2006) 1161. [4] K.R. Harris, M. Kanakubo, L.A. Woolf, J. Chem. Eng. Data 52 (2007) 2425. [5] D. Tomida, A. Kumagai, K. Qiao, C. Yokoyama, Int. J. Thermophys. 27 (2006) 39. [6] A. Ahosseini, A.M. Scurto, Int. J. Thermophys. 29 (2008) 1222. [7] P. Daugé, A.Baylaucq, L. Marlin, C. Boned, J. Chem. Eng. Data 46 (2001) 823. [8] M.J.P. Comuñas, A. Baylaucq, C. Boned, J. Fernández, Int. J. Thermophys. 22 (2001) 749.


PI-43. Thermal stability and thermodynamic properties of layered oxides NaNdTiO4 и Na2Nd2Ti3O10

Sankovich A.M.1, Zvereva I.A.1, Blokhin A.V.2, Kohut S.V.2

1 - St. Petersburg State University, St. Petersburg, Petrodvorets, Universitetskiy pr., 26, Russia 2 - Belarusian State University, Chemistry Faculty, Leningradskaya 14, 220030 Minsk, Belarus

[email protected]

Layered oxides belong to the compounds perspective for creation of functional materials. Moreover cationic ordered oxides are attractive as precursors in soft chemistry roots for synthesis of new compounds. However for the successful application of these materials it is necessary to have data on a temperature range of their stability.

In report we present results of the study on thermal stability and thermodynamic properties of titanates NaNdTiO4 and Na2Nd2Ti3O10 that belong to the Ruddlesden-Popper phases and built by the intergrowth of alternating layers – Perovskite type blocks and Rock-salt type slabs. Difference of the structure of these compounds consists in the thickness of perovskite layer formed by a two-dimensional net of octahedra TiO6, which in Na2Nd2Ti3O10 is three times more than in NaNdTiO4. Particularity of the structure of both compounds is full ordering of alkaline and rare-earth cations on structural positions in alternating layers (perovskite or rock-salt). Due to this fact considered compounds are less stable than isostructural compounds of alkaline-earth elements in which the rare-earth and alkaline-earth atoms are distributed over the different equivalent positions.

Thermal stability of layered oxides NaNdTiO4 and Na2Nd2Ti3O10 has been investigated by isothermal annealing-quenching method followed by X-ray powder diffraction and SEM analysis and methods of the thermal analysis with constant speed of heating (TGA and DTA) in the range of temperatures 1050 – 1370 K and 1370 – 1670 K, accordingly.

The structure-chemical mechanism of the decomposition of layered structures and temperature intervals of phase transformations are determined. The structure of oxide Na2Nd2Ti3O10 with the threefold thickness of perovskite layer was found to be more heat resistant and moreover it is the product of NaNdTiO4 decomposition parallel with oxides Nd2TiO5 and Nd2Ti3O9. The decomposition of Na2Nd2Ti3O10 occurs at higher temperature 1670 K and results in the appearance of Nd2/3TiO3 and Nd2Ti2O7.

The comparison of oxides stability is carried out in terms of thermodynamic and crystal-chemical point of view. The essential contribution in the phase transformations is brought by the effect accompanying change of the coordination environment of cations Nd+3 (C.N.= 9, 12, 6) and the Ti+4 (C.N.= 6, 5) and considerable distortions of their coordination polyhedra. The difference in the length of Na+–O bond connecting various layers, taking into account the identical coordination environment of alkaline cations


(C.N.= 9) in both structures, results in the greater stability of Na2Nd2Ti3O10 layered structure in comparison with the NaNdTiO4.

Heat capacities (Cp) of NaNdTiO4 and Na2Nd2Ti3O10 in the intervals of (7.2 to 368.5) K and (5.2 to 367.5) K were determined in a Termis TAU – 10 adiabatic calorimeter.

Heat capacities of NaNdTiO4 and Na2Nd2Ti3O10 were found to increase regularly at T < 340 K. Anomalous change of heat capacity with temperature was registered above T = 340 K. The observed heat capacity dependence in the studied interval may indicate that a phase transition occurs above the highest point of the measuring range of the calorimeter (370 K).

Heat capacity of Na2Nd2Ti3O10 was found to increase with temperature decrease in the range of (5.2 to 7.4) K. This anomaly is likely to be related with electronic transitions (probably, Schottky effect), which are typical for 4f-element oxides in the low-temperature region.

Standard molar thermodynamic functions for the compounds were calculated in the range of (5 to 370) K. Standard heat capacity, entropy, derived enthalpy and derived Gibbs energy are equal to (152.3 ± 0.6) J⋅K–1⋅mol–1, (176.4 ± 0.8) J⋅K–1⋅mol–1, (92.33 ± 0.40) J⋅K–1⋅mol–1 and (84.07 ± 0.36) J⋅K–1⋅mol–1, respectively for NaNdTiO4 and (351.5 ± 1.4) J⋅K–1⋅mol–1, (392.6 ± 1.7) J⋅K–1⋅mol–1, (207.5 ± 0.9) J⋅K–1⋅mol–1 and (185.1 ± 0.8) J⋅K–1⋅mol–1

, respectively for Na2Nd2Ti3O10.

This work was supported by Russian Foundation for Basic Research (N 09-03-00853).


PI-44. Thermogravimetry study of ion exchange and hydratation processes in complex layered titanates and

tantalates

Chislov M.V., Silyukov O.I., Zvereva I.A.

Department of Chemistry, Saint Petersburg State University, Saint Petersburg, Russia

[email protected]

Layered complex perovskites are intergrowths of layers with different types of structures. They consist of two-dimensional perovskite slabs interleaved with cations or cationic-oxygen units. In recent years layered perovskites have attracted considerable attention because of their interesting physical 2D-properties, such as ion conductivity [1] and photocatalysis [2]. They also can be used as an easily synthesized [3] precursor for obtaining a number of other layered compounds by ion-exchange and topochemical reactions. Alkali forms of layered compounds can undergo proton-exchange and alkali-hydration processes, that is why there is considerable interest in investigation of the behavior of alkali-containing layered structures in water solutions and ambient air.

In this work the results of TGA investigation of ion exchange and hydration processes in complex layered titanates NaLnTiO4 (Ln = La, Nd) and tantalates MNdTa2O7 (M = Li, Na, K, Rb, Cs) are represented. The amount of water intercalated and the exchange degree were estimated from TGA-data. Thermogravimetry (Netzsch TG 209 F1 Iris) was performed in temperature range 30-800oC with heat speed 2 and 5Co/min. Powder X-ray analysis (Thermo ARL X’TRA) was used to specify the structure of compounds. SEM images of obtained compounds (Carl Zeiss EVO 40EP) were used to study the morphology changes.

Investigation of hydration in layered tantalates MNdTa2O7 (M = Li, Na, K, Rb, Cs) has showed that only NaNdTa2O7 forms compounds intercalated by water molecules. According to the experimental data it was found that depending on temperature and relative humidity two stable forms of hydrates exist: NaNdTa2O7•1,35H2O and NaNdTa2O7•0,60H2O.

In the case of NaLnTiO4 new compounds with general formula HxNa1-xLnTiO4*yH2O with H+ ions and water molecules in the interlayer space were obtained in water and acid solutions [4]. It was found that NaLnTiO4 readily exchanges interlayer Na+ ions with water protons forming partially substituted hydrates HxNa1-xLnTiO4 at pH>7 and fully substituted HNdTiO4 without intercalated water at pH<5.

The behavior of layered complex perovskites in aqueous systems demonstrates two main phenomena - instability and tendency for the formation of solid solutions and interlayer hydrates.


This work has been supported by the RFBR (Grant 09-03-00853) and FTP “Scientific and scientific-educational staff of the innovative Russia” (Contract P58)

References [1] D.K.Pradhan, B.K.Samantaray, R.N.P.Choudhary, A.K.Thakur. Materials Science and Engineering, 116, (2005) 7-13. [2] M. Machida, K. Miyazaki, S. Matsushimab, M. Arai. Journal of Materials Chemistry, 13, (2003) 1433–1437. [3] I.A. Zvereva, O.I. Silyukov, A.V. Markelov, A.B. Missyul’, M.V. Chislov, I.A. Rodionov, D.Sh. Liu. Glass Physics and Chemistry, 34, (2008) 749–755. [4] I.A. Zvereva, O.I. Silyukov, M.V. Chislov. Russian Journal of General Chemistry, 81 (2011) in press.


PI-45. Thermodynamic properties and low-temperature phase transition of the Aurivillius phase Bi2NdNbTiO9

Missyul A.B.1, Zvereva I.A.1, Blokhin A.V.2, Kohut S.V.2

1 - St. Petersburg State University,St. Petersburg, Petrodvorets, Universitetskiy pr., 26, Russia 2 - Belarusian State University, Chemistry Faculty, Leningradskaya 14, 220030 Minsk, Belarus

[email protected]

The Aurivillius phases [Bi2O2][An-1BnO3n+1] are well-known ferroelectrics with high Curie temperatures. Recently this class of compounds attracted significant attention due to possible multiferroic and photocatalytic properties. Even though the high-temperature properties of such compounds are described quite well, the data on their properties below room temperature are scarce. Presented in the current work are the results of the thermodynamic investigation of the Aurivillius phase Bi2NdNbTiO9.

The compound has been obtained by the standard ceramic route, the structure of the obtained compound has been confirmed by the X-ray and neutron diffraction.

Heat capacity (Cp) of Bi2NdNbTiO9 in the interval of 5÷370 K was determined in a Termis TAU – 10 adiabatic calorimeter. Standard heat capacity, entropy, derived enthalpy and derived Gibbs energy for the compound were calculated. The maximum error in heat capacity measurements with this calorimeter did not exceed ±4·10−3Cp in the temperature range of 20÷370 K, ±1·10−2Cp in the range of 10÷20 K, and ±2·10−2Cp at T < 10 K.

Heat capacity of the compound was found to increase regularly above T = 18.3 K. The “shoulder”-like anomaly, has been observed on the heat capacity curve between 7.3 and 18.3 K. The enthalpy of transition was evaluated by numerical integration of the excess Cp in the transition region. The temperature Тtr ≈ (12.5 ± 0.5) corresponding to a maximum in the Cp curve was assumed to be the phase transition temperature.

The experimental values of heat capacity of the compound below 8.3 K were found to be sufficiently described by Cp = aT n

equation with the exponent n = (2.4 ± 0.1). The deviation of n from the Debye cubic law corresponds to the strongly anisotropic layered structure of Bi2NdNbTiO9 (that can be described as transitional from two to three dimensional).

The nature of the low-temperature phase transition has been investigated by electromagnetic properties measurements and neutron diffraction. The magnetoelectric coupling of the magnetoresistive type has been observed below the transition temperature. This result, as well as neutron diffraction data, gives rise to the assumption that the observed phase transition is due to the 2D magnetic ordering of the Nd3+ ions.


PI-46. Carbon dioxide capture using chemical absorbents: a thermodynamic approach

Simond M., Ballerat-Busserolles K., Coulier Y., Rodier L., Coxam J.-Y.

Thermodynamique et Interactions Moleculaires, CNRS, UMR 6272, Univ. Blaise Pascal, BP 10448, F-63000 CLERMONT-FERRAND, FRANCE

[email protected]

Greenhouse gases are responsible for the global warming. Anthropic emission of carbon dioxide represents about 70% of the total effect. One option to fight against this environmental problem consists in reducing CO2 emissions in industrial effluents.

Industrial CO2 capture processes are based on repeated absorption-desorption cycles of CO2 in selective absorbents such as amine aqueous solutions. These solutions are known for being efficient chemical solvents for the CO2 capture. A first pilot plant has already been tested in Denmark (CASTOR project). This installation uses monoethanolamine aqueous solutions to capture CO2 from power plant emissions. This plant is efficient but cannot be used in industrial sites because of economical reasons.

Researches are actually carried out on both absorbent selection [1,2,3] and process optimization in order to reduce total cost of CO2 capture. Thermodynamic properties are essential to study gas dissolution and to design capture process units.

Reliable experimental thermodynamic data of absorbent solution, such as excess properties and equilibrium constants, and of gas dissolution, such as solubility and enthalpy of dissolution of CO2, are needed to optimize the processes. Moreover, the development of thermodynamic models is essential to correlate and predict vapour-liquid equilibria and enthalpic data.

This presentation will focus on the acquisition of thermodynamic data. Those data will be used to optimize the semi-empirical parameters in the thermodynamic representation of the gas – absorbent systems.

References [1] L. Rodier, K. Ballerat-Busserolles, J-Y. Coxam, J. Chem. Thermodynamics, 42 (2010) 773-780 [2] H. Arcis, L. Rodier, K. Ballerat-Busserolles, J-Y. Coxam, J. Chem. Thermodynamics, 40 (2008) 1022-1029 [3] H. Arcis, L. Rodier, K. Ballerat-Busserolles, J-Y. Coxam, J. Chem. Thermodynamics 41 (2009) 836–841


PI-47. Phase and chemical equilibrium in reacting system acetic acid – ethanol – ethyl acetate – water

Toikka M.A., Trofimova M.A., Tsvetov N.S.

Saint-Petersburg State University, Department of Chemical thermodynamics and kinetics

[email protected], [email protected], tsvet.nik@mail

The investigation of phase transitions accompanied by chemical reaction is of importance for design of energy- and resource-saving industrial chemical and separation processes. The completion of chemical reaction is often limited by chemical equilibrium between reactants and products, so many industrially important chemical processes must include following separation of equilibrium mixture and recycling of the reactants. Also the limited miscibility in reacting mixture may substantially influence on the run of chemical reaction and complicate the industrial process. Thereby coupled processes combining phase transition and chemical reaction has been intensively studied during recent decades. Generally these researches are theoretical and concerned with reactive distillation – combination of distillation and reaction [1, 2]. Except for practical application the study of the simultaneous phase and chemical equilibrium makes contribution in the development of fundamental thermodynamic theory: it gives, for example, new data on structure and peculiarities of phase diagrams and on critical states in multicomponent reacting systems. However it should be noted that in spite of applied and fundamental importance of systems with simultaneous phase and chemical processes there is a lack of theoretical and especially experimental data on these systems. Some new interesting experimental results and detailed thermodynamic considerations had been recently presented in paper [3] and [4], respectively.

This work presents an experimental research of solubility, liquid-liquid equilibrium (LLE), chemical equilibrium (CE) and critical phenomena in the system with chemical reaction at 293.15 K. The reacting system investigated is acetic acid – ethanol – ethyl acetate – water system. That is the industrially important system with ethyl acetate synthesis reaction. The solubility and critical phenomena were studied by cloud-point technique method. LLE and CE were investigated using gas chromatography. The new experimental data sets on the run of solubility curve were obtained for two ternary sub-systems with limited miscibility (acetic acid – ethyl acetate – water and ethanol – ethyl acetate – water systems). The compositions of critical points in both sub-systems were determined. The same experiments were carried out for quaternary reacting system acetic acid – ethanol – ethyl acetate – water: the surfaces of solubility and chemical equilibrium in the composition tetrahedron were constructed. The relevant experimental data sets were calculated using VBA module based on UNIFAC.


References [1] Kenig E.Y., Bäder H. et al, Chemical Engineering Science, (2001), V. 56, 6185-6193. [2] Sundmacher K. and Kienle A. (Eds.) Reactive Distillation – Status and Future Directions, Wiley-VCH, Weinheim, (2003). [3] Toikka M.A., Gorovits B.I., Toikka A.M., Russian Journal of Applied Chemistry, (2008), V. 81, No 2, 223-230. [4] Toikka A.M., Toikka M.A., Pure and Applied Chemistry, (2009), V. 81, 1591-1602.


PI-48. Thermodynamics and ion flotation of lanthanoides

Lobacheva O.L.1, Dzhevaga N.A.1, Litvinova T.E.1, Chirkst D.E.1, Toikka M.A.2

1 - Saint-Petersburg State Mining University, Department of General and Physical Chemistry 2 - Saint-Petersburg State University, Department of Chemical thermodynamics and kinetics

[email protected]

Ion flotation is the separation of surface inactive ions by foaming with a collector which yields an insoluble product, particularly if the product is removed as a scum [1]. Usually the surfactant (named collector) is an ion of opposite charge to the surface – inactive ion (colligend), and thus cations and anions are floated with anionic and cationic collectors, respectively [2].

The main task of the work is to present a new experimental and theoretical data on the foam separation process in rare earth elements aqueous dilute solutions. The present work is concerned with the use of sodium dodecyl sulphate (SDS) as collector for the removal of samarium (III) and europium (III) from aqueous nitrate solutions by ion flotation. Because the sublate in ion flotation is a chemical compound of the collector and the colligend, the ratio of the two required for complete flotation must at list be a stoichiometric one: Ln+3 + 3 DS- = Ln(DS)3 (Ln – Sm+3 or Eu+3, DS- - dodecyl sulphate- ion). Cations of the Sm+3 and Eu+3 were removed by SDS in a typical laboratory flotation machine 137 B-FL with a flotation cell 1,0 dm3 of capacity. The initial concentration for the nitrate salts of these elements was 10-3 mol/kg. Thermodynamic characteristic such as distribution (Kdistr.) and removal (Krem.) coefficients of ion flotation process in solutions with rare earth elements were obtained. Kdistr. was calculated in accordingly with the formula: Kdistr.=[Ln+3]org/[Ln+3]aq. To sum up, maximum value of Kdistr. of Sm+3 is equal 82, while Kdistr. (Eu+3) ≈ 220. Optimal regime of the removal of Sm+3 is observed that pH of the hydroxides formation is equal 6.49. Eu+3 is floated in the form of basic dodecylsulfates by pH =6.3. Flotation experience in mineral flotation and wastewater treatment should lead to new procedures in the mineral and metallurgical industry.

Acknowlegments This work was supported by the Russian President Program “Leading Scientific Schools of Russian Federation” 6291.2010.3 and the Ministry Program of Education and Science of Russian Federation, project 2.1.1/973 (2009-2011).

References [1] F. Sebba. Ion flotation. American Elsevier, New York, (1962), 165 p. [2] R. Lemlich. Adsorptive Bubble Separation Techniques, Acad. Press, N.Y., (1970), 332 p.


PI-49. Phase behavior of Methane - Toluene - Asphaltene mixture

Varet G.1,2, Daridon J.L.2, Montel F.1

1 - TOTAL 2 - UPPA LFC

[email protected]

Extra heavy oils are a major challenge for the oil industry in the coming years. Thermal processes require large amount of steam and produced huge amount of CO2, a greener alternative is the vapor extraction process, based on solvent injection at reservoir temperature.

Heavy oils contain a significant amount of asphaltenes and the impact of this fraction on phase behavior on the oil/solvent mixture is almost unknown.

The aim of our study was to provide accurate thermodynamic data on mixture of asphaltene and light components. Because of the high viscosity of the crude, direct measurements of oil and gas mixture are difficult and inaccurate.

In order to distinguish between the oils properties and the asphaltene fraction we extracted the asphaltene fraction from a crude and we dissolved this fraction in toluene. Methane was added gradually to this mixture up to 80 mole%.

The phase behavior of the mixtures was determined from ambient to 100°C and compare to the behavior of binary methane- toluene mixture with the same relative ratio methane/toluene.

The results show two different regimes: at low methane/toluene ratio, the bubble point difference between binary and ternary mixture increases gradually. This difference reaches a maximum at 40% ratio, up to 40 bars, and disappears at very high methane/toluene ratio.

The boundary between the two regimes coincides with the flocculation threshold of asphaltene.

This unique set combined with density measurements allow to tune the EOS parameters for methane/asphaltene interaction.


PI-50. Gas solubility in extra heavy oils by impedance analysis of quartz crystal resonators

Daridon J.L.1,2, Cassiède M.1,2, Pauly J.1,2, Paillol H.2,3

1 - Laboratoire des Fluides Complexes 2 - Université de Pau

3 - Laboratoire de Génie Electrique

[email protected]

Due to the increasing demand for oil and to face the depletion of natural resources, the petroleum industry has resorted to exploit heavy oil and extra heavy oil fields. These oil reserves are huge but their exploitation has proved to be difficult and very costly because of the high viscosity of the fluid. Efficient and economical techniques that reduce oil viscosity must be designed to enhance oil recovery and improve the production quantities. Heating by steam injection is a common way to reduce oil viscosity. However, this technique is highly energy-consuming. Another method which enables viscosity reduction consists in blending oils with lighter fractions such as kerosene distillates or even gas mixtures. In this last case, the nature of the gases and the optimal injection conditions must be chosen as a function of the phase behavior of the pseudo binary systems gas + heavy oil. Unfortunately, phase equilibrium measurements are extremely difficult to perform in such systems by conventional PVT techniques owing to the extremely long time needed to reach equilibrium during both compression and depressurization processes and due to the risk of forming stable foamy oils by stirring the mixture.

To overcome this drawback, linked to the kinetic of gas solubilisation in high viscous oils, an experimental technique was designed to shorten the time by reducing the size of the oil sample. This technique rests on the application of quartz crystal resonators as physical sensors to probe the mass and the rheological behaviour of soft matter. It consists of monitoring the conductance spectrum along a wide frequency range of a thickness-shear quartz resonator coated by a viscoelastic film and fully immersed in a pressurized gas. This measurement enables to determine the frequency shift and the half-band-half-width variation caused by coating the quartz surface. These data, recorded for several overtones, provide sufficient information for extracting at the same time the mass and shear moduli of the viscoelastic layer. Finally, comparison of the experiments performed with and without gases allows to evaluate the gas influence on the deposited material and in particular its change in mass.

The technique was used to quantify the solubility of carbon dioxide and methane in various heavy oils and extra heavy oils coming from Canada and Venezuela at pressure up to 50 MPa and in the temperature range 263.15 - 373.15 K .


PI-51. Liquid-Solid Phase Transition Determination and Characterisation of the Solid Deposit in Condensate Under

High Pressure Conditions

Pauly J.1, Daridon J.L.1, Valbuena V.2

1 - LFC - University of PAU 2 - Central University of Venezuela

[email protected]

Crude oils and condensate gases contain long-chain n-alkanes which can precipitate as waxes during production or transportation when the temperature decreases below the wax appearance temperature which can be higher than 50°C in some particular oils. Deposition of these waxes on the pipe walls of production equipments as well as along the flow lines reduces the diameter of the lines and may obstruct them completely if the phenomenon is not stopped. To prevent this problem it is essential to predict the wax appearance conditions as well as the behavior of the solid deposit in function of the pressure. As the precipitation of waxes is mainly induced by a cooling of the fluid, most of the works conducted on the formation of waxes in crude oils has been restricted to the wax appearance temperature measurement at atmospheric pressure. However, the pressure influence on the wax appearance temperature cannot be negligible. Thus a high pressure apparatus which rests on a polarizing microscope has been designed to determine visually the liquid-solid phase transitions in complex waxy systems under high pressure. The experimental apparatus is primarily composed of a high pressure cell made up of a stainless steel autoclave block in which two transparent windows are positioned face to face. These transparent windows are made up of a sapphire cylinder and in order to avoid birefringence phenomena in sapphire. The high pressure cell is incorporated in a polarizing microscope made up of a halogen light source, a polarizer, a moving stage, an infinity corrected objective, an analyzer, an ocular and a video camera. Due to the high thickness of the transparent windows (Sapphire + plug), the objective used is an infinity corrected objective with a long working distance. A filtering device under high pressure has been inserted before the optical cell. This filtering system, which consists of a variable porosity filter (from 0.5 µm to 60 µm) fixed in a filter holder that can stand up to 100 MPa, is connected to high pressure cell whereas the outlet part is connected to a manual high pressure pump. The temperature of the filtration device is perfectly controlled by an external regulation. Therefore, isobaric filtrations can be considered. The WDT (Wax disappearance temperature) of the filtrate is then directly measured in the optical cell and then recuperate for analysis. These apparatus were used to assess the wax appearance temperature of the condensate of a gas condensate as well as the WDT of the filtrate and composition of deposits formed as a function of pressure.


PI-52. Quartz crystal resonators for the detection of asphaltene flocculation

Daridon J.L.1, Cassiède M.1, Carrier H.1, Pauly J.1, Paillol J.H.2

1 - Université de Pau - Laboratoire des fluides complexes 2 - Université de Pau - Laboratoire de Génie Electrique

[email protected]

Since 1837 and its first definition, asphaltenes are defined according to their tendency to flocculate and precipitate in aliphatic solvents such as heptane or pentane and to dissolve in aromatic solvents such as toluene, xylene. Despite that rough definition, oil fields management cannot be done without a careful analysis of asphaltenes related risks especially for offshore concerns. Their presence is taken into account at all the stages of field’s development and exploitation. Indeed during production, transportation and treatment, asphaltenic crude oils may be responsible for partial or complete blocking of reservoir’s rocks, pipelines or valves, due to changes in pressure, temperature or oil composition. Asphaltenes are also known to be surface active compounds that promote emulsions stability with the formation of rigid skin, but also deactivating catalysts due to their high metals content.

The complexity of crude oils, mixtures containing thousands of compounds and as much as chemical or physical interactions, lead to a partial understanding of the key parameters and of the rules involved and/or controlling asphaltene phase behavior. Unquestionable progress have been made in the last decade but modeling and predicting with a good accuracy asphaltene flocculation, deposition amount, or sticking properties are still big issues today.

Several techniques have been developed and then used as routine tests to monitor asphaltene stability in dead crude oils at ambient conditions as refractive index measurement, optical microscopy, light transmittance, acoustic resonator, viscosimetry or conductivity measurements, filtration to name a few of them. However, they all have their own drawbacks, among which the minimum size of the aggregates that is required to be detected.

In order to design a reliable technique to assess the onset of flocculation we have studied the electrical response of a quartz resonator in contact with various fluids containing asphaltenes. The results obtained clearly show that both dissipation and resonance frequency are very sensitive to the onset of flocculation and these properties can be used to monitor flocculation during dynamic processes.


PI-53. Dispersions of carbon nanotubes in a mixed polar solvent

Venediktova A.V.1, Obraztsova E.D.2, Vlasov A.Yu.1

1 - Department of Chemistry, St.Petersburg State University 2 - A.M. Prokhorov General Physics Institute, Russia Academy of Sciences

[email protected]

A pre-requisite for the use of carbon nanotubes, and inter alia single-wall carbon nanotubes (SWCNT), in a number of applications is exfoliation and solubilization of their feed material (which is apt for jostling in bundles), and preparation of stable dispersions in media germane to a specific purpose. A plethora of possible applications poses a question of getting dispersions which are stable over a broad interval of temperatures and meet certain requirements regarding a set of their physical properties. We tackled preparing time-stable SWCNT dispersions with fluidity spanning room and sub-zero temperatures (down to –50 oC) and provide the density, viscosity and vaporization heat optimal for manifesting non-linear optical effects. To this end we processed suspensions in a binary solvent, viz., water-glycerol, with sodium dodecyl benzene sulfonate (SDBS) as a surfactant for stabilizing dispersions. SWCNT for this study were produced by arc discharge in A.M.Prokhorov General Physics Institute, RAS. Dispersions of SWCNT were ultra-sonicated (400 W, Up200h Hilschler) during 1-1.5 hours and centrifuged at 180000 g during 1 hour (Ultracentrifuge Optima Max-E, Beckman-Coulter). Optical absorption spectra of dispersions were registered with a spectrophotometer Lambda-950 (Perkin-Elmer). We prepared dispersions in a water-glycerol eutectic solution (67% wt glycerol) with the freezing temperature – 46 oC. Solubilization of SWCNT was implemented by a standard succession of ultrasonication in the presence of SDBS at concentration equal to ca 4-7 times its critical micellar concentration (CMC) in aqueous solutions and centrifugation. Absorption spectra of the dispersion show peaks at wavelengths ca 690 and 1011 nm corresponding to metallic E11 and semiconductor E22 transitions in nanotubes. Transmission of the dispersion equals 52% at wavelength of 532 nm. The prepared samples sustain their spectra for ca 2 months. Macroscopic properties of the dispersing medium in the vicinity of the eutectic point are analyzed alongside with the phase behavior of SDBS in a binary solvent (CMCs and Krafft temperatures). The data on the dispersion stability with respect to the temperature drop is provided. The information about SWCNT suspensions in the mixed solvent water-glycerol indicate that the time stability of dispersions relevant for a number of applications can be attained. The time stability is complemented by a broad temperature interval of the system fluidity. AVV and AYV acknowledge St.-Petersburg State University for a research grant (#12.37.127.2011) and RFBR (grants #09-03-00746-a and #11-03-01106-a).


PI-54. Sorption and anomalous diffusion of pentane in polystyrene

Smolná K., Hájová H., Nistor A., Chmelař J., Gregor T., Kosek J.

Institute of Chemical Technology Prague

[email protected]

Polymeric foams represent the broadly used material in today’s technology. Numerous reasons for their wide application are primarily light weight, thermal and electrical insulation, energy absorbing performance (shock, vibration, sound, etc.) and impact strength. Solubility and diffusion of solvent in the polymer affects the efficiency of the foam production. Type and concentration of dissolved blowing agent influence the final properties of the foam such as density, strength and insulating properties.

The evolution of concentration profile of solvent in the spherical polymer particle or in the planar film is known in the case of simple Fick’s diffusion very well. However, the diffusion front can proceed through the polymer particles in the case of diffusion in the glassy polymers. This diffusion front causes the glass-plastic transition which is the phase transition of second kind. The anomalous diffusion with the diffusion front is called Case II diffusion. The combination of both diffusion types can also occur. The goal of this contribution is to estimate which kind of diffusion mechanism take place during the sorption of pentane into polystyrene (PS).

Experimental measurements were conducted in gravimetric and video-microscopy apparatuses. Results of gravimetric experiments give us sorption and diffusion data which allow us to estimate parameters of polystyrene-pentane equilibrium model and of several models of penetrant diffusion in PS. The obtained solubilities were compared to the results obtained from the perturbed-chain statistical associating fluid theory (PC-SAFT). Video-microscopy observation of diffusion front during impregnation of PS particle by pentane pointed to the diffusion mechanism in the polymer particle to be the Case II diffusion. Foaming experiments were intentionally provided under conditions of incomplete impregnation so that the resulting particles contain unfoamed compact core in the middle of the PS particles. Morphology of foamed particles was studied by several methods including AFM and X-Ray tomography techniques.


Figure 1: a) Foamed particle taken by X-Ray tomography with compact core;

b) Concentration profile of Case II diffusion.

Diffusion of pentane in polystyrene is very important also in industrial applications because pentane is used as the foaming agent for polystyrene foam production. Diffusion of pentane in polystyrene influences not only homogeneity of PS particles impregnation but also the morphology of resulting foam. On the other hand, the diffusion of pentane from impregnated PS particles occurs in the down-stream processing. Thus the thin desorbed layer on particle surface strongly influences the quality of manufactured foam.

Figure 2: Comparison of experimental data and PC-SAFT predictions for the cosorption of

iso-pentane and n-pentane in PS.


PI-55. Modelling of high-impact polystyrene evolution using the Cahn-Hilliard approach

Vonka M.1, Šeda L.2, Kosek J.1

1 - Institute of Chemical Technology Prague, Technicka 5, Prague 6 Dejvice 166 28, Czech Republic 2 - BASF

[email protected]

The high-impact polystyrene (HIPS) is produced by the free radical polymerization of styrene in the presence of polybutadiene (PB). The formed PS is highly incompatible with the PB. At low conversion of styrene a phase separation takes place by mechanisms of nucleation or spinodal decomposition. The emerging phases are in thermodynamic equlibrium but increasing amount of PS in the system, grafting of the styrene onto the PB backbone, stirring of the mixture and interfacial forces lead to further morphology evolution. The morphology of HIPS can be desribed on two levels, (i) the micron sized PB domains distributed through the continuous PS phase, (ii) submicron PS occlusions inside the PB domains. This morphology is also known as the “salami” morphology. The model is based upon the modified Cahn-Hilliard equations and attempts to qualitatively describe the morphology evolution of the “salami” morphology of HIPS.

Our model takes into account the reaction of styrene, polymer grafting, shear effects in viscous fluids, change in molecular weight of polymers etc., and is capable of describing the nucleation, spinodal decomposition, phase inversion, Ostwald ripening, coagulation and enhancement of the surface during grafting effects. Modelled 2D profile of the “salami” morphology is shown in Fig. 1. The thermodynamics of the model is based on diffusion driven by gradients of chemical potentials which are expressed by the Flory-Huggins equation for the Gibbs free energy of mixing. The Landau-Ginsburg functional approximates the surface tension between emerging phases by introducing an energy paremeter term into the Gibbs free energy of mixing. Suitable thermodynamic parameters for the dynamic simulations are investigated in a triangle phase diagram shown in Fig. 2. Understanding of the morphology evolution with all important phenomena by means of computer simulation will open possibilities for improving the properties of heterophase materials, namely the impact resistance and gloss.


Figure 1. Modelled “salami” morphology. PS phase is red, PB phase is blue.

Figure 2. Ternary phase diagram.

References [1] Alfarraj A., Nauman E. B.: Spiniodal decomposition in Ternary systems with

significantly Different Component Diffusivities, Macromolecular Theory and Simulations 16, 627-631 (2007).

[2] Estenoz D., Vega J., Oliva H., Meira G.: Grafting efficiency in high-impact polystyrene by SEC combined with theoretical prediction-sec model, Journal of Liquid Chromatography & related technologies volume 25 issue 18, 2781-2793 (2002) .

[3] Leal P. G., Asua J. M.: Evolution of the morphology of HIPS particles, Polymer 50, 68-76 (2009).

[4] Nauman E. B., He D. Q.: Nonlinear diffusion and phase separation, Chemical Engineering Science 56, 1999-2018 (2001).


PI-56. Influence of polyolefin particles morphology on their transport properties

Zubov A., Šeda L., Bobák M., Kosek J.

Department of Chemical Engineering, Institute of Chemical Technology Prague

[email protected]

Transport of monomers and diluents in porous polyolefin particles growing in gas- and liquid-dispersion reactors affects not the only the rate of polymerization and the rate of particle growth, but also several important properties of the produced particle, such as copolymer composition distribution within the particle and the particle morphology. Moreover, transport characteristics of polyolefin particles have a strong impact on the degassing of polymer powder in the down-stream processing. This contribution can be divided into three parts. First, the methodology of digital reconstruction of spatially three-dimensional polyolefin particle morphology using X-ray tomography images is presented. Advantages as well as problems and limits associated with the X-ray micro-tomography imaging of polymer samples are critically examined. The second part describes the mathematical model of transport and reaction in porous polyolefin particles with real structure. The developed software allows dynamic simulations of penetrant transport in spatially three-dimensional domain of polymer particle, where the penetrant diffusion coefficient in pores is up to four orders higher than in polymer. We also present combined reaction-diffusion model of polymerization in digitally reconstructed polyolefin particles. Last part of the contribution deals with experimental validation of presented methodology. Because of complex morphology of polyolefin particles, their degassing characteristics cannot be approximated by simple Fick’s law. Developed software for simulation of dynamic degassing allows good prediction of the course of degassing and

the simulated data were validated by experiments carried out using gravimetrical apparatus. Moreover, simulations of copolymerization of ethylene and 1-hexene indicate that the ethylene mass transport limitations occurring in large compact blocks of polymer present in fully grown polyolefin particles significantly contribute to the nonuniform distribution of comonomer in the copolymer.

Figure. Left: Cross-section cut through digitally reconstructed polyethylene particle. Right: Calculated concentration profile of ethylene resulting from polymerization reaction inside the PE particle.


PI-57. Combination of COSMO-RS and MD for Prediction of Phase Equilibria in Systems Containing Large Molecules

Sponsel E., Mokrushina L., Arlt W.

Chair of Separation Science and Technology, Friedrich-Alexander-University of Erlangen-Nuremberg

[email protected]

In the field of chemical engineering and life sciences, the modelling of thermodynamic properties is of growing interest. Among the quantum mechanics based models applied in this field, COSMO-RS (Conductor-like Screening Model for Real Solvents) has become the most popular and effective to predict phase equilibria in complex multicomponent systems based only on the chemical structure. As shown by our group, the results of the prediction strongly depend on the choice of conformations (the minimum-energy conformer does not necessarily give the best prediction). For small molecules with few conformations, adequate results can be obtained based on the Boltzmann-weighted mixture of conformations obtained from the common conformational analysis. On the contrary, large molecules such as surfactants, drugs etc., can have a huge number of conformations. So to reasonably reduce the computational time, only limited sets of conformations should be used. In this case, however, the prediction results for the activity coefficients vary significantly for the different macromolecule conformation sets. Moreover, the molecule conformations differ in hydrophobic and hydrophilic surrounding which necessitates the adaption of the conformations. Hence, the global objective of our research is a consistent method for the selection of conformation sets for large molecules in different surroundings. The conformation sets obtained by this method should allow for the adequate and, what is more essential, reproducible (set-independent) results for phase equilibria using COSMO-RS.

In the present study, we combine the COSMO-RS model with condensed phase molecular dynamics (MD) simulations to model the partition equilibria in surfactant-containing systems. The partition coefficients of homologous series of small solutes (alkanes, alkanols, ketones, aromatics etc) between micellar and water phases in aqueous mixtures of nonionic (Triton X-100) and ionic (SDS, DTAB) surfactants are predicted by COSMO-RS and compared with experimental values to control the quality of prediction. For this, the large amphiphilic molecule (present in both the micellar and water phase) is first simulated with MD explicitly in hydrophilic surrounding (water) for the water phase and in hydrophobic (octanol) for the micellar phase. Using the conformations obtained from MD in the appropriate medium, an adequate description of the large amphiphiles in the system is given. Then, the whole conformational space is sampled, the conformation sets are extracted from the trajectory file based on different criteria and supplied to the COSMO-RS model to calculate the activity and thus partition coefficients of a series of solutes in the micellar systems. The obtained


partition coefficients are compared to one another to study the reproducibility (set-dependency) of predictions. A commonly used random selection of conformations from the whole conformational space gives scattered, set-dependent results; the sets with larger number of conformations hereby do not give the best predictions. Therefore, different physical parameters are analyzed in order to define an additional criterion for the determination of the region from which the conformations should be taken. Though many conformations are proven possible for a molecule as simulated by MD, obviously not all of them correspond to a good description of the molecule. This is due to the fact that even if those conformations exist, they more or less play the role of a “transition” between favoured conformations. A favoured conformation is the one existing for a longer time, i.e. clusters with higher number of members correspond to favoured conformations, i.e. maxima would occur in distribution functions of the criterion property. The radius of gyration as a measure of size and shape of conformations has been found to be a reasonable characteristic.

The developed method is expected to give consistent and set-independent predictions of phase equilibria not only in surfactant-containing systems but in other complex fluid systems containing large molecules. Additionally, the combination of COSMO-RS and MD can give us an opportunity to foresee the quality of the predictions without any comparison to experimental data. We thank DFG (MO 2199/1-1) for the financial support.


PI-58. Phase Equilibria and Interfacial Properties of the System Carbon dioxide + Water

Niño-Amézquita G., Enders S.

TU Berlin, Germany

[email protected]

The interfacial tension of mixtures plays an important role in industrial processes when various fluid phases are involved, like in distillation columns and enhanced oil and gas recovery. Knowledge on the interfacial tension is needed for process design especially regarding transport properties. Systematic experimental work covering the commonly required large range of conditions is quite costly. For this reason a theoretical method in order to predict the interfacial tension using only bulk properties of the mixture and the surface tensions of pure components is very helpful. One possibility for a theoretical approach is the density gradient theory [1,2,3] or density functional theory in combination with a suitable equation of state. Caused by the important role of the system water + CO2 it is the subject of several experimental and theoretical investigations. The used theories differ by the involved equation of state (SAFT-VR [4], SAFT-MIE [5], PC-SAFT [6], PCP-SAFT [7]). All used theories take the self-association of water into account, however different numbers of association sites were assumed, namely two [6,7] or four [4,5] association sites. Only in the work of Tang and Gross [7] the quadrupole moment of CO2 was considerated in the theoretical framework by the Polar Perturbed Chain - Statistical Associated Fluid Theory (PCP-SAFT) [8], allowing the incorporation of the quadrupole forces without additional adjustable parameter. The experimental data related to phase equilibria over a large temperature and pressure range could be calculated using a polynomial of the second order for the temperature dependency of the binary interaction parameter, kij [7]. The phase equilibria form the essential basis for the calculation of the interfacial properties. This contribution focus on the calculation of the phase equilibria over a wide temperature and pressure range and the calculation of the interfacial properties, like interfacial tension and interfacial profiles, with the help of the PCP-SAFT. In contrast to the model used by Tang and Gross [7] in our theoretical framework we assume four association sites of water, namely the model 4C, instead of two. The pure-component parameters for CO2 were taken from the literature [8], whereas the pure-component parameters for water were readjusted. The estimated parameters are able to describe the pure-component properties (like vapor pressure, density) of both substances close the experimental data. In order to calculate the surface tension of the pure substances the influence parameters κi must be estimated using the surface tension at one temperature. The temperature dependency of the surface tension can be quantitatively predicted in comparison to experimental data. The phase equilibrium calculation of the binary system requires the fitting of the binary interaction parameter kij. The studied system exhibits a vapour-liquid equilibrium (VLE) at low pressures and additionally liquid-liquid equilibrium (LLE) at high pressures. This


situation caused a temperature dependent binary interaction parameter. The temperature dependency was found to be linear in the temperature range between 313K until 343K. A further extrapolation of this dependency to lower temperatures leads to the calculated phase diagram depicted in Figure 1, where the VLE together with the LLE is shown.

0.00 0.01 0.02 0.98 0.99 1.000.0

3.8

7.6

11.4

15.2

19.0

PCP-SAFT kij=-0.1995 Coan and King(1971) King et al.(1992)

CO2 + water298K

P [M

Pa]

XCO2

Figure 1. Experimental [9,10] and calculated phase diagram for the system CO2 + water.

The equation of state is further used to calculate the interfacial properties. The obtained interfacial tensions related to the VLE and to the LLE were compared with experimental data taken from the literature [11,12].

Acknowledgements The authors thank the German Science Foundation DFG (En 291/6-1) for financial support.

References [1] J.W. Cahn, J.E. Hilliard, J. Chem. Phys. 28 (1958) 258. [2] C.I. Poser, I.C. Sanchez, Macromolecules 14 (1981) 361. [3] S. Enders, K. Quitzsch, Langmuir 14 (1998) 4606. [4] A. Georgiadis, F. Llovell, A. Bismarck, F.J. Blas, A. Galindo, G.C. Maitland, J.P.M. Trusler, G. Jackson, J. Supercrit. Fluids 55 (2010) 743. [5] T. Lafitte, B. Mendiboure, M.M. Piñeiro, D. Bessières, C. Miqueu, J. Phys. Chem. B, 114 (2010) 11110. [6] X.S. Li, J.M. Liu, D. Fu, Ind. Eng. Chem. Res. 47 (2008) 8911. [7] X. Tang, J. Gross, Fluid Phase Equilib. 293 (2010) 11. [8] J. Gross, AIChE Journal 51 (2005) 2556. [9] M.B. King, A. Mubarak, J.D. Kim, T.R. Bott, J. of Supercrit. Fluids 5 (1992) 296. [10] C.R. Coan, A.D. King, J. Am. Chem. Soc. 93 (1971) 1857. [11] A. Georgiadis, G. Maitland, J.P.M. Trusler, A. Bismarck, J. Chem. Eng. Data 55 (2010) 4168. [12] A. Hebach, A. Oberhof, N. Dahmen, A. Kogel, H. Ederer, E. Dinjus, J. Chem. Eng. Data 47 (2002) 1540.


PI-59. Aggregation Behavior of Pluronic Surfactants

Dorn U., Enders S.

TU Berlin, Germany

[email protected]

Pluronics are nonionic triblock copolymers composed of a central hydrophobic chain of polyoxypropylene (PPO) flanked by two hydrophilic chains of polyoxyethylene (PEO). Because the lengths of the polymer blocks can be customized, many different Pluronics exist that have slightly different properties. Because of their amphiphilic structure, the polymers have surfactant properties that make them useful in industrial applications. Among other things, they can be used to increase the water solubility of hydrophobic, oily substances or otherwise increase the miscibility of two substances with different hydrophobicities. For this reason, these polymers are commonly used in industrial applications, cosmetics, and pharmaceuticals. They have also been evaluated for various drug delivery applications, for instance in chemotherapy.

One of the essential prerequisite for these interesting applications is the knowledge of the intake capacity of the formed aggregates for hydrophobic or hydrophilic guest molecules. If Pluronics are applied for drug delivery purposes, the intake capacity of hydrophobic molecules is the most important criteria, because drugs are usually hydrophobic (i.e. ibuprofen). The drug intake capacity depends from the properties of the formed aggregates. A detailed molecular based thermodynamic model, for instance the model suggested by Nagarajan and Ruckenstein [1,2,3], can be used to predict the aggregation behavior of a surfactant in pure water. The model includes the following effects:

a) dilution of both polymer blocks in water using a Flory – Huggins lattice;

b) deformation of the polymer chains;

c) localization;

d) formation of micellar core-solvent interface;

e) backfolding or looping in triblock copolymers;

The deformation of the polymer chain results from the following situation: In the single dispersed state of the copolymer, both blocks are swollen in water. Both polymer blocks are extended in the micelles and hence the packing parameter will be changed. The localization term arises by the entropy reduction related to the joint linking between both blocks. The most of the discussed effects are influenced by the presence of hydrophobic guest molecules. The guest molecules, which are present in the micellar core, enter the theoretical framework via their interaction energy between guest molecules and PPO and the interfacial tension of water and guest molecules.


This contribution aims to the theoretical prediction of the solubilization capacity of Pluronic P103 having a chemical composition of PEO17PPO60PEO17 for hydrophobic small molecules, namely toluene, cyclohexane and n-hexane using the Nagarajan – Ruckenstein model.

The parameters of the model in order to describe the surfactant are the length of the hydrophobic tail, the lenght of the hydrophilic head and the interaction energy between the PPO unit and water as well as the PEO unit and water. The interaction energies can be obtained with help of Flory – Huggins theory or any other thermodynamic model.

One of the basic ideas in this contribution consists in the estimation of these parameters using the liquid-liquid equilibrium of water and PEO and water and PPO. These parameters can be applied to predict the solubilzation of hydrophobic molecules in aggregates formed by P103 surfactant. One typical result is depicted in Figure 1, where the volume fraction of guest molecules is plotted against the temperature for different hydrophobic chemicals in the micellar core. All the different guest molecules have similar polarity, but different geometrical shapes. The predicted data in Figure 1 show clearly, that the polarity and the shape of the guest molecules have a large impact on the solubilization properties of the formed aggregates.

25 30 35 40 45

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0.35

toluene cyclohexane n-hexane

φ i

T [°C] Figure 1. Predicted solubilisation of P103 surfactant for hydrocarbons.

References [1] R. Nagarajan, E. Ruckenstein, Langmuir 7 (1991) 2934. [2] R. Nagarajan, Structure - performance relationships in surfactants, in K. Esumi (Ed.), New York, Marcel Dekker 1997, pp. 1-81. [3] R. Nagarajan, Coll. Surf. Sci. B: Biointerfaces 16 (1999) 55. [4] S. Enders, D. Häntzschel, Fluid Phase Equilibria 153 (1998) 1-21.


PI-60. Dependence of the micelle DEL on the ion kind and salt addition. Computer simulations with explicit solvent

Brodskaya E.N., Semashko O.V.

Saint-Petersburg State University, Department of Chemistry

[email protected]

The structure of the double electric layer (DEL) is defined by the distribution of the charged components at the interface between phases. As a rule, the polar solvent in the theories of DEL is considered as a continuous medium with the given value of the dielectric permittivity. However, it is obvious that the polar solvent should contribute to the local electric potential. It follows from the existence of the surface potential of pure water. This problem can be directly solved by the computer simulation methods. The main objective of this work is the study of DEL of micelles by MD method in order to elucidate both the role of solvent and counterion nature in the properties to DEL.

The spherical direct micelles of a model anion SAS in water was considered. The direct micelle was modeled as a charged macroion with the solid hydrocarbon core of radius 1.5 nm and with the single point charges uniformly distributed on its surface. The total charge of the micelle is equal to 60e. The macroion charge was neutralized by single charged spherical ions such as Na+, K+, Cs+ and Rb+. The head groups could oscillate relative to equally distributed points of the micelle core. In the systems with salt added (NaCl or KCl) its concentration was about 0.065M. The single micelle was placed into a spherical cell with enough large radius in order to ensure the presence of the bulk solution at some distance from the micelle. No limitations on the range of the interactions were put. The time of calculations was no less than several nanoseconds. The temperature of the systems was about 300 K. The local partial distributions of components, bulk charge distribution ρq(r), and local electric potential ϕ(r) were calculated.

Figure 1. Local charge distribution in DEL of DSS micelle.


In Fig.1, the contributions to the local charge from all the components around the SDS micelle are shown together with the resulting charge distribution. It is seen that the contributions from water and counterions compensate practically each other outside the dense part of DEL. The salt addition to the solvent does not change this conclusion. The only noticeable effect from salt addition is compressing of the DEL. There is no substantial difference between NaCl or KCl.

Nevertheless the influence of the ion nature could be essential for structure of DEL micelle. The change of Na+ subsequently by K+, Cs+ or Rb+ results in compressing of the DEL and micelle itself. The largest effect was observed in the case of Cs+. Water molecules are squeezed out of the inside shell of micelle and micelle ions are shifted closer to the hydrogen core compared to the case of DSS micelle. The radius of the anion shell is decreased on about 0.15nm compared to SDS micelle.

Figure 2. Local electric potential in DEL of DSS micelle with salt addition.

As mentioned above, the total local charge is concentrated in the closest surroundings of the micelle without a noticeable diffusive layer. The consequence of that is quick diminishing of the electric potential outside of the micelle vicinity as it is seen in Fig.2. This fact is inherent for all micelle systems regardless of the counterion nature and salt addition. In the end we can state that the counterion kind and salt addition could only change the structure of micelle itself especially of such as its size and ion shell. The contribution from the polar molecules could result in the complicated behaviour of the local electric potential, which depends on the internal charge structure of the solvent molecules. The main conclusion of the simulations is that the remote part of the micelle DEL is practically defined by polar solvents. That means that the correct theoretical description of DEL requires the accurate taking into account contribution from the solvent structure.

The work was supported by the grant “НШ-6291.2010.3”.


PI-61. Molecular dynamic simulation of AOT aggregation in nonpolar solvent

Mudzhikova G.V., Brodskaya E.N.

Saint-Petersburg State University

[email protected]

Surfactant substances (SAS) are widely employed in modern industry. They are often used as containers for nanosynthesis and storage and transportation of nanoparticles as well. The prevalent containers are reverse micelles and microemulsions water-in-oil. Surfactant solutions in nonpolar medium are less studied than those in water. In order to put some additional component like a nanoparticle, protein, polyelectrolyte or something else inside the container, we should investigate the reverse micelles before. We have to study the micelles structure, behavior and mechanism of micelle formation in nonpolar solvent. The behavior of SAS molecules in oil medium is not the same as their behavior in water.

Reverse micelles of aerosol OT (AOT) because of its wide use as a surfactant substance has been investigated by molecular dynamic simulation. A coarse-grained approach to the AOT- anion modeling is chosen to minimize computational burden. The counterions Na+ are described as separate moving force centers. The SPC/E model is used to simulate the water molecules. All molecules of oil medium are regarded as single Lennard-Jones sites. The simulation has been carried out for the canonical NVT ensemble within a spherical cell at the temperature range of 300 to 250 K.

The aggregates structure is considered by eccentricity, radial distribution functions and pair distribution functions of components. The micelles shape is estimated on the base of eccentricity values.

In the beginning all particles were randomly distributed over the cell. For a nanosecond the ions of AOT have been generating a branched chain-like structure that is in equilibrium with some oligomers and water molecules. Then it is broken into separate spherical micelles. The cores of micelles contain water and counterions. As a result of the present work the hypothesis of the different to that in polar solvents development of micelles formation is confirmed. The early stage of the chain-like structure has not been observed before. The presence of water promotes formation of the spherical reverse micelles.

The work was supported by the Leader Scientific Schools Grant of the President of the Russian Federation (no. NSh-6291.2010.3).


PI-62. Speciation and thermodynamics in solutions of multiply associating ions described using the Binding Mean

Spherical Approximation (BiMSA)

Simonin J.P.1, Bernard O.1, Torres-Arenas J.2

1 - Université P.M. Curie - Paris 2 - Universidad Leon, México

[email protected]

A theoretical description of speciation and of the thermodynamic properties in solutions of multiply associating ions is proposed in the framework of the binding mean spherical approximation (BiMSA) [1-3]. In the MSA the ions are generally regarded as charged hard spheres immersed in a dielectric continuum representing the solvent (water). An interesting feature of this theory is that it yields analytic expressions [1,2]. To account for complex formation, the cation is assumed to possess a finite number of sites on its surface, on which anions can bind [3-5]. Binding is described within the Wertheim formalism.

Figure 1. Sketch of cation with binding sites and of anion (with one site). This property leads to the formation of 1:1, 1:2, 1:3,... complexes according to a stepwise complexation-equilibrium process. Explicit formulas are obtained for the speciation and for the thermodynamic properties (osmotic and activity coefficients). The model accounts for the effect of complexation and electrostatic interactions in a consistent way. The treatment is applied to the case of aqueous solutions containing divalent ions, such as zinc chloride, and of trivalent and tetravalent lanthanides and actinides.

References [1] J.P. Simonin, L. Blum and P. Turq, J. Phys. Chem., (1996), 100, 7704-7709. [2] J.P. Simonin, J. Phys. Chem. B, (1997), 101, 4313-4320. [3] J.P. Simonin, O. Bernard and L. Blum, J. Phys. Chem. B, (1998), 102, 4411-4417. [4] O. Bernard and L. Blum, J. Chem. Phys., (1996), 104, 4746-4754. [5] A. Ruas, O. Bernard, B. Caniffi, J.P. Simonin, P. Turq, L. Blum and P. Moisy, J. Phys. Chem. B, (2006), 110, 3435-3443.

-+


PI-63. Hydrogels from a Polymer Containing Pendant Fragments of Amino Acid Crosslinked by End-Functionalized PEG and Molecular Thermodynamic Modeling of Clustering

in Solution of Associating Chains

Tsyrulnikov S.A., Girbasova N.V., Victorov A.I.

Department of Chemistry, Saint Petersburg State University

[email protected]

Polymer gels play an important role in targeted drug delivery and as scaffolds in tissue engineering. Polyethyleneglycol (PEG) is one of the polymers most widely used for biomedical applications. In this work we modify PEG 2000 by introducing residues of amide of L-aspartic acid, carrying positively charged amino groups, Fig.1a. In aqueous solution formation of polyionic complex with poly (N – acryloyl disodium aspartate), Fig.1b, is expected. Because the products of hydrolysis of these polymers are non toxic the hydrogel formed by self-assembly of these two polymers has good potential for the design of biocompatible and biodegradable materials.

(a) end-functionalized PEG

(b) Poly [N-acryloyl disodium aspartate]

Figure 1. Polymers used to obtain physical hydrogels

The polymers have been synthesized as explained below. PEG 2000 was converted to PEG – bis – amine through PEG ditosylate. The residue of aspartic acid was introduced in PEG – bis – amine by reaction with dimethyl ester of N-acryloyl aspartic acid. Amidation by ethylenediamine and treatment of the product with HCl in dioxane yielded end-functionalized PEG, Fig.1a. Poly [N–acryloyl disodium aspartate] was synthesized by radical polymerization of dimethyl ester of N-acryloyl aspartic acid followed by hydrolysis of ester groups. Structure of synthesized products was proved with H1 – NMR.


Turbidimetric titration of solution of one of the polymers shown in Fig.1 with the solution of the other leads to an increase of the optical density owing to formation of clusters. Evolution from solution of free chains to the gel through clustering is supported by measurements of the viscosity. The size of equilibrium clusters is measured by dynamic light scattering. Polymers of varying chain length have been studied.

For solution of polymer chains with cross-associating sites (e.g., cations and anions in Fig.1), we derive a molecular thermodynamic model that extends the previously known theory of self-association [1]. To take into account formation of cyclic clusters of polymer chains and aggregates with multiply connected chains (ladder-like structures) we introduce heuristic corrections to the classical mean field theory that neglects the presence of such structures.

Our model is applied to study phase behavior, clustering and gelation in polymer solutions. The model describes evolution of the system from free chains to gel and suggests mechanism of cluster formation. Two different types of clusters (a network and a star like branched cluster) are predicted, depending on the relative content of polymers in the aqueous mixture. Our results show substantial effect of multiple bonding on clustering. With increasing molecular weight of the linear polyelectrolyte the model predicts broadening of compositional intervals where gelation is possible. Our theoretical predictions are helpful for the interpretation of experimental data.

For financial support the authors are grateful to St.Petersburg State University, research grant #12.37.127.2011, and to the Russian Foundation for Basic Research, projects #09-03-00746-a and #09-03-00968-a.

References [1] A.Semenov, M.Rubinstein. Macromolecules, 31 (1998) 1373-1385.


PI-64. Prediction of mixed gas solubility and solubility-selectivity in glassy polymers

Minelli M., Campagnoli S., De Angelis M.G., Doghieri F., Sarti G.C.

Università di Bologna

[email protected]

The evaluation of the mixed gas solubility in glassy polymers is of fundamental importance for the development gas separation membranes. For rubbery polymers the usual equation of state (EoS) models, in their multicomponent version, can be conveniently applied to calculate multiple gas solubility in the equilibrium phases; for the case of glassy polymers, on the contrary, the same thermodynamic tool cannot be used. The general approach called Non Equilibrium Thermodynamics of Glassy Polymers (NET-GP) [1], coupled to the Lattice Fluid (LF) model for the representation of substances [2,3], was showed to be able to predict the solubility of gases and vapors in glassy polymers at various pressures based on pure component parameters.

The above approach is here applied to the modeling of multicomponent gas solubility in a pure glassy polymeric matrix, to predict the solubility of binary gas mixtures in pure glassy polymers as CH4/CO2 in Poly(2,6-dimethylphenyleneoxide) (PPO), C2H4/CO2 and N2O/CO2 in poly(methylmetacrylate) (PMMA), at room temperature and at various pressures, for which experimental data are available [4-5]. The presence of polar and swelling penetrants gives rise to significant interactions, which make the solubility of mixed gases differ significantly from the corresponding pure component values. In the above calculations, the gas-polymer binary energetic parameters kij are adjusted on the solubility data of the single gas in the polymer, and the gas-gas binary interaction parameter is considered zero in view of the generally high dilution of gaseous components in the polymer.

In the sorption of pure swelling penetrants, one can assume reasonably that the polymer density decreases linearly with the penetrant pressure, according to a swelling coefficient, ksw, that can be measured directly or evaluated by fitting the pure gas solubility data on the NELF model predictions. The swelling induced by the gaseous mixture in the polymer is then assumed to follow a simple additive rule based on the penetrant partial pressure in the external gaseous phase.

Experimentally it is seen that the N2O content in the PMMA, at given partial pressure of N2O, is lowered by the increase of CO2 partial pressure; the same effect is observed for the CO2/CH4 pair in PPO. The NELF model is able to predict the experimental behavior observed for mixed gases solubility in both systems; the agreement is indeed remarkable in both cases in the whole pressure range investigated. The parameters used for this case are: kCO2/PMMA = -0.015, kN2O/PMMA = 0.007; ksw,CO2 = 15.4 x10-4 bar-1; k

sw,N2O = 18.6 x10-4 bar-1. The present approach allows also to estimate predictively the mixed gas solubility-selectivity of N2/CO2, CO2/CH4 and H2/CO2 mixtures in several


glassy polymers including polyimides such as Matrimid in a wide range of pressures, allowing to detect significant deviations from the ideal selectivity behavior and estimate the separation performance of membrane materials.

References [1] R.H. Lacombe, I.C. Sanchez. J. Phys. Chem. 80 (1976) 2568. [2] F. Doghieri, M. Quinzi, D.G. Rethwisch, G.C. Sarti, in: Materials Science of Membranes for Gas and Vapor Separation, ed. Y. Yampolskii, I. Pinnau, B.D. Freeman, 1:137–58. New York: Wiley, 2006. [3] F. Doghieri, G. C. Sarti, Macromolecules 29 (1996) 7885. [4] E.S. Sanders, W.J. Koros, J. Polym. Sci.: Polym. Phys. Ed. 24 (1986) 175. [5] B.J. Story, W.J. Koros, J. Membr. Sci. 67 (1992) 191.


PI-65. Calculation of the solubility of liquid solutes in glassy polymers

Sarti G.C., De Angelis M.G.

University of Bologna

[email protected]

The interaction between glassy polymers and the external environment is of great importance for the direct application they are used for, e.g. in the packaging of food and pharmaceuticals, protective barriers, membrane separation processes, as well as for the characterization of the environmental stress cracking. The solubility of different penetrants is one of the relevant properties used for several applications as membrane separation processes.

The solubility of liquid molecules in glassy polymers has been considered in this work by using the general results of the Non-Equilibrium Thermodynamics of Glassy Polymers, which proved successful to calculate solubility isotherms of gases in glassy polymers for rather different situations, including polymer blends, mixed gases and mixed matrices. It is shown that the existing nonequilibrium model is suitable also for liquid penetrants in a glassy phase: water and ethanol sorption in polycarbonate (PC) and water sorption in polysulfone (PSf) have been examined as examples. The ability of the model to predict the solubility from both liquid and vapor phases was tested successfully, using the same values of the parameters for both phases. In the case of polycarbonate, the model was also applied to calculate successfully the solubility of liquid water at different temperatures from 25 to 130°C, with a single value of the energetic binary parameter associated to the binary mixture. The results are shown in Figure 1.

The analysis discusses also how the model parameters can be obtained from independent information, the importance to determine the glass transition temperature of the glassy mixture as well as the volume dilation induced by the liquid solutes.


Figure 1. Solubility of liquid water in polycarbonate in the temperature range from 25 to 130 °C: comparison between model predictions and experimental data from ref. [4].

References [1] R.H. Lacombe, I.C. Sanchez. J. Phys. Chem. 80 (1976) 2568. [2] F. Doghieri, M. Quinzi, D.G. Rethwisch, G.C. Sarti, in Materials Science of Membranes for Gas and Vapor Separation, ed. Y Yampolskii, I Pinnau, BD Freeman, 1:137–58. New York: Wiley. [3] F. Doghieri,G. C. Sarti, Macromolecules 29 (1996) 7885. [4] H.E. Bair, G.E. Johnson, R. Merriweather. J. Appl. Phys. 49 (1978) 4976.


PI-66. EoS Modeling of the Phase Behavior of the Ternary System Polylactic Acid (PLA) – Water - 1,4-Dioxane for the

Production of Biodegradable Scaffolds via Thermally Induced Phase Separation (TIPS)

Cocchi G., Doghieri F., De Angelis M.G.

Università di Bologna

[email protected]

Introduction and Background The thermally-induced demixing of polymeric solutions TIPS (Thermally Induced Phase Separation) has become an important technique for the production of microporous polymeric membranes, especially in the biomedical and tissue engineering fields, due to its versatility, simplicity and to the possibility of controlling the final structure of the membrane by acting on the process variables. The TIPS technique has found a preferential application in the production of scaffolds for tissue engineering: such membranes are characterized by an open porous structure, formed by a biocompatible and biodegradable polymer, designed to guarantee the maximum diffusion and penetration of fluids and biomolecules, in order to allow the vascular growth in the implant and to be resorbable in the rigenerated tissue. The TIPS process is characterized by 4 stages: 1) Formation of a homogenous liquid solution of polymer and solvent/s; 2) Pouring of the solution in the desired form; 3) Cooling of the solution to induce demixing; 4) Removal of the solvent-rich phase. In contrast with traditional techniques where the phase separation (stage 3) is induced by the exchange of solvent with an antisolvent, in TIPS the demixing is obtained by simple cooling. Liquid-liquid demixing takes place by nucleation and growth of droplets of a polymer poor phase when the original composition of the solution is rich in the polymer (higher than the critical point concentration). The solution demixes by nucleation and growth of a polymer rich phase when the polymer concentration is low (lower than the critical point concentration). The phase separation can also involve crystallization of the polymer. The structures will grow and coarsen in time. The TIPS has many advantages with respect to other protocols: - It can be applied to a wide number of polymer, even to those with poor solubility and to semycristalline ones. - It allows to obtain a variety of structures, including microporous isotropic matrices suitable for controlled release of drugs. - A lower number of variables has to be controlled in the process (basically the cooling rate). The conditions and mechanism of the phase transition affect markedly the type of structure obtainable via TIPS: it is thus important to develop models able to describe the thermodynamic interactions between polymer and solvents, and to represent the phase diagrams for the systems of interest. In the literature, many works can be found that


investigate the influence of different parameters on the membrane structure, both in the solid-liquid and liquid-liquid demixing: the most interesting systems are those formed poly(lactic acid) (PLA) and copolymers with glycolic acid (PLGA) in solution with dioxane and water.[1] Most of the studies carried on so far on these systems involved the Flory-Huggins model in its multicomponent version and obtained a qualitative agreement.[2] The objective of the present work is to test the applicability of more recent EoS models to the ternary equilibria of the system amorphous PLA-Water-1,4-Dioxane in the polymer-poor region. Results and discussion In this first stage of the study, the chemical potentials, that are required for the equilibria calculations, are computed from the multicomponent formulation of the Lattice Fluid (LF) Equation of State by Sanchez and Lacombe,[3] that has been early recognized to be able to predict phase splitting behavior in polymer-solvent systems. In order to perform the phase equilibria calculations a Matlab® code have been developed and the system of nonlinear equations arising from equating the chemical potentials is solved by means of the non linear least square method built-in function of Matlab®. For the sake of generality and to take into account the possibility to use more complex thermodynamic models such as those based on the SAFT [4] approach, the chemical potential is obtained by numerical differentiation of the expression of the Helmholtz Free Energy for unit of mixture volume, with respect to the density of the chemical species in the mixture. As long as the present approach is based on an EoS model, the density of the mixture is evaluated searching for the roots of the EoS itself. The SL-EOS parameters of water and 1,4-dioxane have been found in the literature, while the polymer ones have been obtained fitting a set of experimental PVT data of the same amorphous PLA used for cloud point measurements. Binary water-PLA and water-dioxane interaction parameters have been estimated by using solubility data of water in PLA at room temperature, and heats of mixing data for the water-dioxane system. Comparison with cloud point experimental data and a sensitivity analysis with respect to the values of interaction parameters have been performed. References [1] Y. S. Nam, T. G. Park, Porous biodegradable polymeric scaffolds prepared by thermally induced phase separation, Journal of Biomedical Materials Research 47, 8–17, 1999. [2] P. Van De Witte, P. J. Dijkstra, J. W. A. Van Den Berg, And J. Feijen, Phase Behavior of Polylactides in Solvent-Nonsolvent Mixtures, Journal of Polymer Science: Part B: Polymer Physics, 34, 2553-2568 (1996). [3] Sanchez I.C., Lacombe R.H. 1978. Statistical thermodynamics of polymer solutions. Macromolecules 11, 1145-56. [4] Huang S.H., Radosz M. 1990. Equation of state for small, large, polydisperse, and associating molecules. Ind. Eng. Chem. Res. 29:2284-94.


PI-67. Sorption and transport of hydrocarbons and alcohols in addition-type poly(trimethyl silyl norbornene):

experimental data and comparison with NELF model predictions

Galizia M.1, De Angelis M.G.1, Sarti G.C.1, Finkelshtein E.2, Yampolskii Y.P.2

1 - University of Bologna 2 - Topchiev Institute of Petrochemical Synthesis, Moscow

[email protected]

The sorption and transport properties of n-alkanes and alkyl-alcohol vapors in addition-type poly(trimethyl silyl norbornene) (PTMSN) were studied at 35°C and at various activity values. PTMSN is a high free volume polymer that shows very high solubility and selectivity to condensable vapors and can be considered a promising material for several applications, such as gas/vapor membrane separations.

Sorption and diffusion experiments with n-alkanes (n-C4, n-C5, n-C6) and alkyl alcohols (CH3OH, C2H5OH, n-C3H7OH) were performed as well as dilation measurements with n-C5 and n-C6, at 35°C. The behavior of the alcohol vapors differs from that of alkanes, mainly for the shape of the solubility, diffusivity and mobility isotherms: this phenomenon, as well as the diffusion trend of the different vapors, was explained by the different interactions between the penetrants and the hydrocarbon-based polymer.

The permeability isotherms were also obtained from solubility and diffusivity data, showing that the permeability of PTMSN lies in between those of other high free volume glassy polymers as AF2400 and PTMSP. Finally, the dependence of the transport parameters of n-alkanes in PTMSN on penetrant pressure and molecular weight was analyzed, discussed and compared to that observed in other high free volume glassy polymers. The activity-based solubility coefficients of alkanes in PTMSN show a weak dependence on the molecular weight, while in PTMSP they increase and in AF2400 they decrease with as molecular weight of penetrant increases.

The sorption and swelling of alkane and alcohol vapors in PTMSN were analyzed and compared to the predictions of the Non Equilibrium Lattice Fluid (NELF) Model. The characteristic parameters for the Lattice Fluid (LF) equation of state required by the model were determined for PTMSN by fitting the infinite dilution solubility of a wide series of penetrants. The solubility isotherms of alkanes and alcohols were then compared with the NELF Model calculations: for the case of alcohols, which exhibit a peculiar sorption behavior, a good agreement is observed between experimental and calculated data, as it can be seen in Figure 1. For n-alkanes an even more accurate representation of the solubility is given by the model (Figure 2), which also provides an estimate of the average swelling induced by vapor sorption, that is consistent with the swelling experimentally measured.


The model is also able to represent the dependence between the observed solubility and the penetrant molecular weight, in PTMSN as well as in other high free volume glassy polymers. In particular it was noticed that the model can predict the different trends of the solubility encountered in PTMSP (activity-based solubility increasing with alkane molecular weight), Amorphous Teflon 2400, (activity-based solubility decreasing with alkane molecular weight) and PTMSN (activity-based solubility constant with alkane molecular weight). The reason for this different behavior is due to the balance between the energetic and entropic contributions to solubility in the various polymers: the energetic term increases with MW, due to higher interactions with the polymers, while the entropic term decreases with MW, due to the fact that larger penetrants have lower configurations available in the polymer matrix. Therefore, the total solubility might increase or decrease with MW depending on the balance between the two factors. Such indications may be very useful in determining the selectivity behavior of glassy polymers used as selective layers in membrane devices for gas and vapor separation.

Therefore, use of the NELF model not only enables us to predict the solubility isotherm but also to better understand what are the physical mechanisms which affect the observed behaviour.

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Figure 1. Experimental and theoretical solubility isotherms of alcohols in PTMSN at 35°C and comparison with NELF model.


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/gpo

l)exp. dataNELF model with kij=0.0, ksw=0.0NELF model with kij=-0.05, ksw=0.38

Figure 2. Experimental and theoretical solubility isotherms of n-butane in PTMSN at 35°C and comparison with NELF model.


PI-68. Molecular dynamics study of solubilization in ionic micelles

Drach M., Narkiewicz-Michałek J., Niedziółka K., Sienkiewicz A., Szymula M.

Maria Curie-Skłodowska University, Faculty of Chemistry, Maria Curie-Sklodowska Sq. 3, 20-031 Lublin, Poland

[email protected]

Solubilization phenomenon has attracted attention and interest of many researchers over decades. This attention is due to a broad range of solubilization applications in biological, pharmaceutical and industrial processes.

Despite the experimental and theoretical work, some aspects of the phenomenon remain poorly understood. One of the theoretical approaches to study surfactant micelles is using a realistic model of water and surfactant molecules (all atom simulations). The AA simulations provide detailed information on micelle structure i.e. radius of gyration, area per headgroup, etc. and are a promising way of micelle structure with solubilizate studies.

In this work, the all atom molecular dynamic simulations of hexadecyltrimethylammonium bromide (HTAB) in the presence of phenol and butanol molecule are presented. The simulations were performed for the systems with different solubilizate:surfactant and phenol:butanol:surfactant ratios. All simulations were carried out using GROMACS 4.07 package [1,2]. Simulations were performed in the NPT ensemble. The temperature was kept at 300.15 K by applying the Nose-Hoover thermostat whereas the pressure was held constant at 1 bar using the Parinello-Rahman barostat. The all atom (AA) model was used to describe surfactant molecules. The parameters for this model were taken from OPLS-AA potential [3]. Parameterization details can be found in paper [4]. The water molecules were represented by the SPC/E potential. The starting configurations for investigated systems were prepared using PACKMOL package [5].

Fig. 1. RDF for butanol molecule, BR- ion and head group of surfactant molecule with respect to the micelle (center of the mass).

Fig. 2. Time evolution of solubilized butanol molecules number.


Fig. 3. Radial distribution function for oxygen atom in butanol and phenol molecule, bromide ion, head group of surfactant molecule and the 4th carbon in the surfactant alkyl chain.

Fig. 4. Time evolution of solubilized butanol and phenol molecules number.

The results can be summarized as follows:

- The estimated HTA+ micelle radius is equal to 2.17 nm, i.e. the area per head group is about 0.85 nm2. - About 45 bromide ions are placed at the distance less then 3 nm from HTA+ micelle center of mass, i.e. 65% of micelle charge is screened by Br- ions. - The -OH groups of solubilized butanol and phenol molecules are placed at the distance of about 1.85 nm from the center of mass of the HTAB micelle. - The solubilized butanol and phenol molecules penetrate HTAB micelle to the forth carbon in the alkyl chain of surfactant molecule. - In the investigated systems the competition between solubilized molecules was not observed. References

[1] H. J. C. Berendsen, D. van der Spoel and R. van Drunen, Computer Physics Communications 91 (1995) 43-56.

[2] B. Hess, C. Kutzner, D. van der Spoel, and E. Lindahl, Journal of Chemical Theory and Computation 4 (2008) 435-447.

[3] W.L. Jorgensen and J. Tirado-Rives, J. Journal of the American Chemical Society 110 (1988) 1657-1666.

[4] M. Jorge, Langmuir 24 (2008), 5714-5725. [5] L. Martínez, R. Andrade, E.G. Birgin and J. M. Martínez, J. Comput. Chem. 30

(2009) 2157-2164.


PI-69. Antioxidants Activity in Emulsions Stabilized by Ionic Surfactants

Szymula M., Sienkiewicz A., Narkiewicz-Michałek J., Niedziółka K., Drach M.


[email protected]

Various methods are used to assess quantitatively the electron-donating capability of antioxidants in microemulsions [1,2]. One of the most popular and most effective is cyclic voltammetry which gives electrochemical characteristics that allow us to better understand the antioxidant’s action in the systems of practical use.

In this communication the cyclic voltammetry with the glassy carbon electrode has been used to investigate the behaviour of two antioxidants: ascorbic acid (AA) and α-tocopherol (α-T) in microemulsions stabilized by anionic (SDS/pentanol/water) and cationic (CTAB/octane/butanol/water) surfactants. These antioxidants have completely different hydrophilic/hydrophobic character. From the obtained results it follows that in the microemulsions the oxidation process of AA is more difficult than in water solutions. In both microemulsions the oxidation potential is much higher and the peak current much lower than in the buffer solution. For water insoluble α-T the peak potential increases gradually when the microemulsion changes from the oil-in-water (o/w) to water-in-oil (w/o) whereas the peak current first increases (o/w) and then decreases (w/o) with the increasing butanol content. Our results confirm the view that the redox parameters of antioxidants depend on which part of the microemulsion phase the antioxidant molecules are located in. The influence of the microemulsion properties (charge and size) on the apparent diffusion coefficient of antioxidants and thus their transport to the electrode surface is discussed.

References [1] M. Drach, J. Narkiewicz-Michalek, A. Sienkiewicz, M. Szymula and C. Bravo-Diaz, Colloids Surfaces A, DOI: 10.1016/j.colsurfa.2010.11.073. [2] M. Szymula, J. Narkiewicz-Michałek, J. Applied Electrochem., (2009), 31, 681-687.


PI-70. Vitamin C Antioxidative Activity in Microemulsions

Narkiewicz-Michałek J., Szymula M., Sienkiewicz A., Drach M., Niedziółka K.


[email protected]

It is well known that the activity of antioxidants depends not only on their molecular structure but also on the character of the medium in which the oxidation process occurs. Several studies have shown that vitamin C (ascorbic acid, AA) is less stable in surfactant solutions and microemulsions than in pure aqueous solution and that the rate of its decomposition increases with decreasing polarity of the system. The aim of this presentation is to compare the results of atmospheric oxidation of vitamin C in microemulsions stabilized by nonionic (TX-100), anionic (SDS) and cationic (CTAB) surfactants. The investigated microemulsion regions contained an inverse micellar solution, the basis for W/O microemulsions, a bicontinuous part (BC), and the aqueous micellar solution that forms the basis for O/W microemulsions. It was found that the rate of vitamin C oxidation strongly depends on the character of surfactant polar head. In the microemulsions stabilized by cationic surfactant the rate of vitamin C decomposition was smaller than in the aqueous solution whereas in microemulsions stabilized by anionic and nonionic surfactants the opposite trend was observed.

Figure 1. Values of AA oxidation initiation rate vs. alcohol content in the microemulsion (BC – bicontinuous system).

Another conclusion that follows from our investigations is that the rate of ascorbic acid atmospheric oxidation depends on the type of microemulsion. It is higher in the water-in-oil (W/O) than in the oil-in-water (O/W) microemulsion and increases with the increasing oil content.


PI-71. Thermodynamic properties for the heterogeneously catalyzed selective oxidation of cyclohexane in carbon dioxide

expanded media by experiment and molecular simulation

Merker T.1, Vrabec J.2, Hasse H.1

1 - Laboratory of Engineering Thermodynamics, University of Kaiserslautern, Erwin-Schrödinger-Straße 44, 67663 Kaiserslautern, Germany

2 - Thermodynamics and Energy Technology, University of Paderborn, Warburger Str. 100, 33098 Paderborn, Germany

[email protected]

The development of novel octahedral molecular sieves is of particular interest for the catalytic oxidation of cyclohexane in carbon dioxide expanded media. In this project, the thermodynamic properties of the relevant mixtures are investigated. Therefore, the mixtures of interest are studied with respect to the gas solubility both by experiment and molecular simulation.

A literature survey shows a lack of gas solubility data for carbon dioxide and especially oxygen. In a first step, the Henry’s law constant of carbon dioxide in pure cyclohexane and in pure cyclohexanone as well as in mixtures of these components is measured between 298 and 393 K. Secondly, the gas solubility of oxygen in pure cyclohexanol is measured. A synthetic method is used for the experiments.

Molecular simulations are performed with multi-center Lennard-Jones models with superimposed electrostatic sites. For some of the components of interest, molecular models are available in the literature [1]. For cyclohexane, cyclohexanol [2] and cyclohexanone new molecular models are developed in this work. Furthermore, a new, improved carbon dioxide model is developed [3]. Unlike interactions are modeled with the modified Lorentz-Berthelot combination rule. The predictions from simulation are compared to the present experimental Henry’s law constant data, which are in a good agreement. Additionally, high pressure vapor-liquid equilibria of the mixtures are predicted. Finally, predictive results for transport properties are presented. References [1] Vrabec, J.; Stoll, J.; Hasse, H. J. Phys. Chem. B (2001) 105: 12126-12133. [2] Merker, T.; Vrabec, J.; Hasse, H. Soft Materials (2010) in press. [3] Merker, T.; Engin, C.; Vrabec, J.; Hasse, H. J. Chem. Phys. (2010) 132: 234512.


Nitrogen adsorption on SBA-15 silica

0

2

4

6

8

10

12

14

0 0.2 0.4 0.6 0.8 1Relative pressure

Solv

atio

n pr

essu

re (M

Pa)

QSDFTDBdB

PI-72. Adsorption-Induced Deformation of Mesoporous Solids

Gor G.Yu.

Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, USA

[email protected]

In the course of gas adsorption-desorption cycles the volume of porous adsorbents non-monotonically changes. This phenomenon, called adsorption-induced deformation, has been known for decades [1], however, the theory is still lacking. The theory of adsorption-induced deformation was presented recently for different microporous materials: zeolites [2] and carbons [3]. Experiments show [1,4] that adsorption-induced deformation of mesoporous materials is qualitatively different from the microporous ones.

We exploit thermodynamic approach (suggested in [2,3] for micropores) to couple adsorption stress with the grand potential of the pore with adsorbed fluid. We use two different methods to obtain the grand potential as a function of adsorbate pressure. The first one is Derjaguin – Broekhoff - de Boer (DBdB) macroscopic theory [5,6], which describes the interactions of the adsorbed phase with the substrate in terms of disjoining pressure [7]. This method allows us to derive analytical expressions for the dependence of the adsorption stress on the adsorbate pressure, and demonstrates semi-quantitative agreement with experimental data [1,4]. However, because of its macroscopic nature, DBdB theory works worse for mesopores smaller 8 nm.

We also use quenched solid density functional theory (QSDFT) [8] to calculate the grand potential and describe adsorption deformation. Since QSDFT does not exploit macroscopic values (surface tensions, disjoining pressure, etc.), its predictions have no lower limit on the pore size. We also show on example of nitrogen and argon adsorption on porous silica, that for pore size ~8 nm and larger the predictions of QSDFT and DBdB theories fairly coincide. It should be noticed that comparison of our results with experimental strain isotherms can serve as an indirect method for measuring the solid-liquid surface tension, which is not readily available. This comparison also provides an estimate of the bulk modulus of saturated and partially saturated porous bodies.


References [1] Amberg, C. H.; McIntosh, R., Can J Chem, 1952, 30, 1012-32. [2] Ravikovitch, P. I.; Neimark, A.V., Langmuir, 2006, 22, 10864-8. [3] Kowalczyk, P; Ciach, A.; Neimark, A.V., Langmuir, 2008, 24, 6603-8. [4] Prass, J.; Muter, D.; Fratzl, P.; Paris, O., Appl Phys Lett 2009, 95, (8) 083121. [5] Derjaguin, B. V., Acta Physicochimica URSS 1940, 12, 181. [6] Broekhoff, J. C. P.; de Boer, J. H., Journal of Catalysis 1967, 9, (1), 8-14; 15-27. [7] Gor, G. Yu.; Neimark, A. V., Langmuir, 2010, 26, 13021-7. [8] Ravikovitch, P.I.; Neimark, A.V., Langmuir, 2006, 22, 11171-9.


PI-73. Phase behavior of systems containing biofuel components and 1,3-dioxolane derivatives as additives:

experimental study and modeling

Yakovleva M.A.1, Vorobyov E.N.1, Prikhodko I.V.1, Pukinsky I.B.1, Smirnova N.A.1, Bölts R.2, Constantinescu D.G.2, Gmehling J.2

1 - Department of Chemistry, Saint Petersburg State University, 198504 Universitetsky pr., 26, St.Petersburg, RUSSIA

2 - Department of Industrial Chemistry, Institute for Pure and Applied Chemistry, Carl von Ossietzky University of Oldenburg, D-26111 Oldenburg, GERMANY

[email protected]

During recent years there is a growing interest to cyclic ketals (polyol derivatives), and this is due to a great extent to perspectives of application of these compounds as additives to biofuels improving their characteristics, such as the octane number and phase stability.

In this paper thermodynamic properties of several systems containing cyclic ketals (ethers) are considered, with special attention to the phase behavior of mixtures of 1,3-dioxolane derivatives with hydrocarbons (n-heptane, toluene), ethanol and water. The studies were performed using a variety of experimental methods (polythermal and isothermal LLE measurements, refractometry, static method for VLE study, flow and titration calorimetry, gas-liquid chromatography).

New experimental VLE and LLE data for binary, ternary and quaternary systems containing 2,2-dimethyl-1,3-dioxolane-4-methanol (later Dioxolane) are presented. This 1,3-dioxolane derivative is a product of the chemical reaction between glycerol and acetone.

Static VLE measurements were performed for binary mixtures of Dioxolane with water (40˚C), ethanol (80˚C) and heptane (50˚C). For all three binaries small positive deviations from the ideal behavior were observed. Using the flow calorimeter, the concentration dependence of the excess enthalpy was determined for the binaries at 25 and 50˚C. LLE studies were performed for binary and ternary mixtures of Dioxolane with water, ethanol and heptane. The Dioxolane - heptane mixtures exhibit the miscibility gap with the upper critical solution temperature 33,5˚C. Two other liquid binaries show complete miscibility at temperatures under study (above - 30 ºC). LLE data (binodal curves and tie lines) at 20 ºC were obtained for ternary systems Dioxolane + heptane + water, Dioxolane + heptane + ethanol and Dioxolane + toluene + water, some sections of the quaternary system with a fixed Dioxolane content were also tried. To estimate the influence of the hydrocarbon nature on the phase behavior we performed LLE studies for mixtures where toluene is used instead of heptane.


The group contribution models UNIFAC and Modified UNIFAC (Dortmund) were applied to calculate VLE and LLE in the systems formed by Dioxolane, water, ethanol and heptane. The interaction parameters for the main group cyclic ether “cy-CH2O” were revised using the experimental data obtained in our study. The results of correlation and prediction for the investigated systems are presented. In the model LLE calculations not only 2,2-dimethyl-1,3-dioxolane-4-methanol but several other 1,3-dioxolane derivatives were tried as additives to heptane + ethanol + water and toluene + ethanol + water.

The experimental data obtained and model predictions of the effect of cyclic ketals on the phase behavior of hydrocarbon + alcohol + water mixtures can be helpful in the search of additives improving the phase stability of biofuels.

Authors are thankful to RFBR (grant #10-03-00419) and DAAD (grant #A/10/01071) for the financial support.


PI-74. Line Tension of Crystal with Dispersion Forces

Rusanov A.I.

St. Petersburg State University

[email protected]

The thermodynamic line tension κ of a crystal edge is defined as an excess quantity with respect to cleavage work σ for the crystal faces meeting at a given edge:

0

[ ( ) ]x dx∞

∞κ ≡ σ − σ∑∫ . (1)

Here ( )xσ is the local cleavage work at a crystal face, ∞σ is its constant value far from a given edge and x is the distance from the edge. The local cleavage work itself can be directly calculated from the local cohesive force ( , )f h x as

2 ( ) ( , )x f h x dh∞

δ

σ = ∫ , (2)

where δ is the crystal spacing and h is the separation value in the course of cleavage. The local cohesive force was calculated earlier for a cubic crystal with dispersion forces (without retardation) as [1]

[ ]4

15( , ) ( , ) ( , )32 h

dzf h x A x z x z hz

∞π= ϕ + ϕ −∫ , (3)

where , ij i ji j

A A≡ ρ ρ∑ ( ijA is the pair potential constant, iρ is the molecular number

density of component i) and 3 5

2 2 1/ 2 2 2 3/2 2 2 5/2

2( , )( ) 3( ) 5( )

x x xx zz x z x z x

ϕ ≡ − ++ + +

. The

final result is [2]

[ ]40 1

45 ( / , ) ( / , ) 18 H

dzdh x z x z h dxz

∞ ∞ ∞ κ = ϕ δ + ϕ δ − − σδ ∫ ∫ ∫ (4)

or, after numerical calculation, / 0.676∞κ σ δ ≈ − , which makes a simple relation between line tension, cleavage work, and crystal spacing. References [1] A.I. Rusanov and F.M. Kuni, J. Chem. Phys., (2009), 131, 106101-106102. [2] A.I. Rusanov, J. Chem. Phys., (2009), 131, 244713-244714.


PI-75. Thermodynamic modeling of alternative refrigerants

Vilaseca O.1,2, Llovell F.1,2, Marcos R.M.3, Vega L.F.1,2

1 - Institut de Ciencia de Materials de Barcelona. Consejo Superior de Investigaciones Cientificas. ICMAB-CSIC. Campus UAB. 08193 Bellaterra. Barcelona. Spain

2 - MATGAS Research Center (Carburos Metálicos/Air Products Group, CSIC, UAB). Campus UAB. 08193 Bellaterra. Barcelona. Spain

3 - Department of Mechanical Engineering. ETSE. Universitat Rovira i Virgili. 43007 Tarragona. Spain

[email protected]

Hydrofluorocarbons (HFCs) have been used in the last years as common refrigerants, substituting the classical chlorinated compounds (CFCs and HCFCs), once it was shown that the latter ones are a major source of inorganic chlorine in the stratosphere and destroyers of the ozone layer [1].

The characterization and optimization of the thermodynamic properties of refrigerants, such as density, vapor pressure, solubility of components, interfacial properties, etc., represent a key part of both theoretical and experimental work before they are put into their final use.

In this contribution, we present a thermodynamic characterization of selected HFCs using the extended soft-SAFT equation of state (EoS) [2–4], including phase equilibria and interfacial tensions. An appropriate molecular model is proposed for the different refrigerants, looking for the transferability of the molecular parameters. Several correlations with the molecular weight and the number of carbons are proposed, in order to be able to predict the properties of other HFCs. The interfacial tension of these compounds is obtained using the soft-SAFT EoS with the Density Gradient Theory approach (DGT) [5, 6]. Prediction of derivative properties is also included, with good agreement with experimental data.

Once the pure compounds have been well characterized, the vapor-liquid equilibrium of several mixtures of refrigerants between them and with carbon dioxide and alkanes are revised [7]. In most of the cases, a fully predictive approach without any binary parameter is enough for a good representation of the thermodynamic diagrams in the range of conditions of industrial application.


Figure 1. Vapor–liquid equilibria for the systems a) R125 + butane at 278K (triangles) and

298K (circles) b) R134a + butane obtained by soft-SAFT (lines), compared to exp. data [8] at 313K (triangles), 323K (circles) and 333K (squares).

F. Llovell acknowledges a JAE-Doctor fellowship from the Spanish Government. This work has been partially financed by the Spanish government, Ministerio de Ciencia e Innovación, under projects CTQ2008-05370/PPQ and NANOSELECT and CENIT SOST-CO2 CEN2008-01027 (a Consolider project and CENIT project, respectively, both belonging to the Ingenio 2010 program). Additional support from Carburos Metálicos, Air Products Group, and the Catalan government, under project 2009SGR-666, is also acknowledged.

References [1] World Meteorological Organization. Scientific Assessment of Ozone Depletion:

2006, Global Ozone Research and Monitoring Project-Report No. 50; Geneva, Switzerland, 2007.

[2] F.J. Blas, L.F. Vega, Molecular Physics 92 (1997) 135-150 [3] F. Llovell, J.C. Pàmies, L.F. Vega, J. Chem. Phys., 121 (21) (2004) 10715-10724 [4] F. Llovell, L.F. Vega, J. Phys. Chem. B 110 (2006) 1350-1362 [5] J. D. van der Waals, Z. Phys. Chem. Leipzig 13 (1894) 657-725 [6] J. D. van der Waals, Translated by J.S. Rowlinson. J. Stat. Phys. 20 (1976) 197-244 [7] O. Vilaseca, F. Llovell, J. Yustos, R.M. Marcos, L.F. Vega, J. Sup. Fluids, 55 (2010) 755-768. [8] J. Im, M. Kim, B.G. Lee, H. Kim, J. of Chem. & Eng. Data 50 (2005) 359–363.


PI-76. Self-assembly of Small Organic Molecules in Aqueous Solutions

Subramanian D.1, Anisimov M.A.1,2

1 - Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742, USA

2 - Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA

[email protected]

Motivated by controversies in the literature regarding the microscopic and mesoscopic inhomogeneities in some aqueous solutions, we have performed static and dynamic light-scattering experiments in aqueous solutions of tertiary butyl alcohol. In addition to the molecular scale concentration fluctuations, we have found the presence of reproducible mesoscopic inhomogeneities, which become especially pronounced below room temperature. We find that the observed inhomogeneities are self-assembled near-spherical Brownian aggregates of a size from a hundred to a few hundred nm. We have shown that these aggregates are long-lived clathrate-like precursors triggered by minute traces of specific impurities (in particular, propylene oxide) present in these solutions.


PI-77. Surface Tension: a new equation based on the corresponding state principle

Di Nicola G., Moglie M.

Università Politecnica delle Marche

[email protected]

This work presents a new formula for the surface tension prediction of refrigerants.

Experimental surface tension data were collected after a careful literature survey for the following pure fluids: R11, R12, R13, R13B1, R14, R21, R22, R23, R32, R113, R114, R115, R123, R124, R125, R134, R134a, R141b, R143a, R152a, R218, R227ea, R236ea, R236fa, R245ca, R245fa, R365mfc and R1234yf.

Experimental data were correlated with the most important semi-empirical correlating methods based on the corresponding state theory existing in the literature: the Miqueu et al. equation [1], the Pitzer equation [2], the Brock et al. equation [3-4], the Sastri and Rao equation [5], and the Schmidt et al. [6] equation.

To minimize the deviation between the predicted data and the experimental data and to find the optimal equation for experimental data regression, a (µ+λ)-Evolution Strategy was adopted. After a careful statistical analysis of the results, a new formula based on the corresponding state principle and on the Golden Ratio with improved representation of the experimental results was found and proposed. The new formula was named Aurum equation.

References [1] Miqueu, C.; Broseta, D.; Satherley, J.; Mendiboure, B.; Lachaise, J.; Garciaa, A. Fluid Phase Equilib. 172, 169 (2000). [2] Pitzer, K.S. Thermodynamics, McGraw – Hill, (1995) New York. [3] Brock, J.R.; Bird, R.B. AIChE J., 1, 174 (1955). [4] Miller, D.G. Ind. Eng. Chem. Fundam. 2, 78 (1963). [5] Sastri, S.R.S.; Rao, K.K. Chem. Eng. J., 59, 181 (1995). [6] Schmidt, J.W; Carrillo-Nava, E.; Moldover, M.R. Fluid Phase Equilib. 122, 187 (1996).


PI-78. Thermodynamical Basis of Electromagnetic Field Impact on Multicomponent Petroleum Fluids

Kovaleva L., Kamaltdinov I., Idrisova S.

Department of Applied Physics, Bashkir State University, 32, Validy str., 450074 Ufa, Russia

[email protected]

The effect of strong radio-frequency (RF) electromagnetic fields on the multicomponent systems can considerably intensify heat and mass transfer processes, that enables to use these fields in various technological processes, in particular, with heavy oils production increase. In this connection the necessity in theoretical and experimental researches of interaction of RF EM fields with materials of petroleum technology has increased. The materials of petroleum technology are nonmagnetic dielectric substances with weak conductivity, and the dispersion of dielectric permeability of these materials is caused by orientation polarization of their polar molecules.

A peculiarity of interaction of RF EM fields with dispersed systems is the delay of polarizing processes in comparison with change of parameters of the fields. As a result, the process of polarization becomes non-equilibrium and is accompanied by an intensive dissipation of energy of the field. Other peculiarity of RF EM fields is that their period is relatively small for electrodynamics values essential variations. That is why it is necessary to average these values over the period of RF EM field.

The thermodynamics of multicomponent systems with cross transfer effects based on ideas and methods of thermodynamics irreversible processes has been formulated. The numerical evaluation of the thermodiffusion coefficients by comparing experiments and mathematics modeling of a filtration process in multicomponent petroleum fluids under the radio-frequency electromagnetic field influence have been obtained.

Equation of sorption kinetics on the basis of Henry’s law using the thermodynamics study was derived. It shows that RF EM radiation in a working environment, along with disturbed heat sources, is a significant factor affecting the process of formation and destruction of polar oil components' structures.

It has been proved, that in case of interaction of a RF EM field with multicomponent systems with different dielectric permeability of components the not described earlier cross effect - electrothermodiffusion - takes place.

This work was supported by Ministry of Education and Science of the Russian Federation.


PI-79. Solidification of a Binary Mixture: Application to Desalination

Jaouahdou A.1, Safi M.J.1, Muhr H.2

1 - ENIT, Tunisia 2 - LRGP INPL, Nancy, France

[email protected]

Solidification of a binary mixture allows the separation of its various components. The yield of separation is a function of different parameters. In this paper we study the crystallization of the mixture H2O-NaCl which makes it possible to obtain a liquid phase (brine) charged in salt and a solid phase (ice) theoretically made up of pure water and can be fresh water after melting.

A series of experiments of sea water freezing (salt 35 g/l) on a cold wall is carried out at the laboratory under different operating conditions

During these experiments, we focus on the role of each parameter (temperature of crystallization, duration of crystallization, insulation...) being able to impact the final composition of the solution.

After our last studies of freezing from below and from above, we improve with the vertical configuration the yield trying to reach rates of salt making it possible to regard the water produced as drinkable according to the standards of WHO*.


PI-80. CO2 capture and storage: the recent developments

Pires J.C.M., Alvim-Ferraz M.C.M., Martins F.G., Simões M.

LEPAE, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal

[email protected]

The Intergovernmental Panel on Climate Change considers undeniable the warming of the climate system and associates the increase of global average temperature to the observed increase of the anthropogenic greenhouse gas concentrations in the atmosphere. Carbon dioxide (CO2) is one of the most important contributors for the increase of the greenhouse effect. CO2 concentrations are increasing in the last decades mainly due to the increase of anthropogenic emissions. To reduce the effects caused by this environmental problem, several chemical and physical processes were studied to capture CO2 from large emission source points (post-combustion): (i) absorption with amines; (ii) adsorption processes; (iii) polymeric membranes; and (iv) cryogenic separation. Besides post-combustion technology concept, CO2 can also be captured by pre-combustion capture systems or oxy-fuel capture systems [1]. The transportation of resulting streams with high CO2 concentrations is performed by pipelines or ship to places where CO2 is stored. The options for CO2 storage are: geological storage, ocean storage or mineralization. However, these methodologies, known as carbon capture and storage (CCS) technologies, are considered as short-term solutions, as there are still high process costs and also concerns about the environmental sustainability of CO2 storage. This study presents the most recent research directions for CO2 capture and storage processes.

References [1] J. Gibbins and H. Chalmers, Energy Policy, (2008), 36, 4317-4322.


PI-81. CO2 capture by microalgae: environment, energy and resources

Pires J.C.M., Alvim-Ferraz M.C.M., Martins F.G., Simões M.


[email protected]

The use of microalgae is an emerging technology for CO2 capture. These microorganisms can fix CO2 using solar energy with efficiency 10 times greater than terrestrial plants [1]. The photosynthesis that naturally occurs in the ocean is responsible for approximately 40% of the overall amount of carbon annually fixed on the planet [2]. As a biological process, the CO2 capture using microalgae is considered an environmental sustainable method to reduce the CO2 concentrations in atmosphere. These microorganisms use directly the solar energy to convert the CO2 into biomass. This biological process was tested for CO2 capture from flue gas [3]. The major concerns were the increase of temperature and the reduction of pH of the culture medium. However, some microalgae species were able to capture CO2 and also NOx and SO2. An important requirement of microalgae growth is the access to important elements (C, N, P and S). These elements can be found in wastewaters and the cultivation of microalgae in these mediums could have two environmental benefits: CO2 capture and wastewater treatment [4, 5]. Additionally, an important advantage of this mitigation process is the extraction from the resultant biomass of: high-value biomolecules, human food source, aquaculture/animal feed, cosmetics, medical drugs, fertilizer and biodiesel [1].

The microalgal CO2 capture is still not economically competitive with carbon capture and storage technologies. An extensive research based on the design of the bioreactors should be performed. Besides not being the first choice for microalgae culture at large scale, the closed bioreactors have several advantages in comparison with open pounds: (i) better control of the cultivation conditions; (ii) less space requirement; (iii) reduced water loss by evaporation; and (iv) reduced loss of CO2 to atmosphere. However, the investment and operational costs are very high. Another relevant area of study is the influence of photoperiod and the distribution of light inside the bioreactor. This is one of the key issues that limit the industrial application of this method. Additionally, the biorefinery concept should be applied to microalgal CO2 mitigation to improve the economical potential of this process. This study presents the most relevant research directions for CO2 capture by microalgae.


References [1] K. Skjanes, P. Lindblad and J. Muller, Biomolecular Engineering, (2007), 24, 405-413. [2] E. Jacob-Lopes, C.H.G. Scoparo and T.T. Franco, Chemical Engineering and Processing: Process Intensification, (2008), 47, 1371-1379. [3] K. Maeda, M. Owada, N. Kimura, K. Omata and I. Karube, Energy Conversion and Management, (1995), 36, 717-720. [4] Y.S. Yun, S.B. Lee, J.M. Park, C.I. Lee and J.W. Yang, Journal of Chemical Technology & Biotechnology, (1997), 69, 451-455. [5] E. Jacob-Lopes, C.H.G. Scoparo, M.I. Queiroz, and T.T. Franco, Energy Conversion and Management, (2010), 51, 894-900.


PI-82. Genetic programming based method to estimate binary gas diffusivity

Pires J.C.M., Martins F.G.


[email protected]

This study aims to estimate the binary gas diffusivity using genetic programming (GP). Due to the complexity of this problem, GP is an adequate methodology as it can optimize, simultaneously, the structure of the model and its parameters. It is an artificial intelligence methodology that uses the same principles of the Darwinian Theory of Evolution. GP enables the automatic generation of mathematical expressions that are modified following an iterative process applying genetic operations [1].

The inputs of the models were the temperature, critical temperature, critical volume and molecular weight of each component of the binary mixture. The model performance was evaluated using a test set that was not used in the model development. Moreover, the achieved model overperformed other correlations found in literature.

References [1] J.C.M. Pires, M.C.M. Alvim-Ferraz, M.C. Pereira, F.G. Martins, Expert Systems with Applications, (2011), 38, 1903-1908.


PI-83. Thermodynamic properties of aqueous-alcohol solutions of sodium chloride

Konstantinova N.M., Mamontov M.N., Uspenskaya I.A.

Moscow State University, Chemistry Department, Laboratory of Chemical Thermodynamics

[email protected]

Aqueous solutions containing salts are of increasing importance and influence on separation processes in chemical engineering (recrystallization and extraction). The solutions of sodium chloride in water-organic solvents, which consist of normal and isomer alcohols CnH2n+1OH (n = 2-5), were chosen as the investigation’s objects in the present work. The one of the purposes of the investigation was to reveal a correlation between thermodynamic properties of solutions and structural characteristics of alcohols to predict behavior of uninvestigated mixtures.

The mean activity coefficients of NaCl in mixed water-alcohol solvents in ternary solutions were determined by electromotive force method (EMF) at 288-323 K in the following ion-selective electrodes (ISE) cells without transference:

Na- ISE | NaCl (m) + H2O(100-wAlc) + Alc (wAlc) | Cl-ISE.

The obtained results produced good internal consistency for all the studied temperatures. Integral solution’s properties were calculated with various types of solution’s description like the Pitzer’s, the Pitzer-Simonson, eNRTL models and the Darken method. The influence of model’s choosing on the calculations results was analyzed. As an example of the results, the mean ionic activity coefficients for sodium chloride in NaCl–H2O-1-C3H7OH and Gibbs energy of mixing in NaCl-H2O-C2H5OH system at 298.15 K calculated by the mentioned model approximations are shown in Figure 1.

The standard Gibbs energies (∆trG) and enthalpy of sodium chloride transfer from water to mixed solvents were calculated from cell potentials. The obtained results are in satisfactory agreement with literature data [1,2]. Figure 2 a shows ∆trG vs. n (number of carbon atoms in iso-alcohol) for ternary solutions with wAlc = 5 % at 298 K. An estimation of the primary hydration number (Nhyd) of sodium chloride was made with the Feakins and French equation [3]. This value varies from 8 for methanol to 0.5 for butanol and coincides for different homologs of alcohols within error.


(a) (b) Figure 1. Thermodynamic properties of ternary solution at 298.15 K: (a) mean ionic coefficient of NaCl in NaCl-H2O-1-C3H7OH system and (b) lines on isothermal section of the surface of Gibbs energy for NaCl-H2O-C2H5OH system

(a) (b)

Figure 2. Plot of (a) ∆trG vs. n (in CnH2n+1OH) and (b) Nhyd vs. n.; filled symbols – the present work, transparent symbols – [1-2]. T = 298.15 K

The research work was financially supported by RFBR ( 09-03-01066-а).

References [1] J. Mazzarese, O. Popovych, J. Electrochem. Soc. (1983), 130, 2032-2036. [2] D.Y.Chu, J. Chem. Soc. (1987), 83, 635-644. [3] D.Feakins, C.M.French. J.Chem.Soc. (1957), 2581-2589


PI-84. Thermodynamics Modeling of Dissociation Conditions of Clathrate Hydrate Refrigerants R-134a, R-141b and R-

152a using the CPA equation of state

Nikbakht F.1, Izadpanah A.A.1, Varaminian F.2

1 - Persian Gulf University 2 - Semnan University

[email protected]

Using the cubic plus association equation of state (CPA) and van der Waals –Platteeuw model, hydrate Dissociation Conditions of Clathrate Hydrate Refrigerant R-134a, R-141b and R-152a is modeled. Based on the reference parameters for sI and sII reported by Sloan (1998), Kihara potential parameters for these materials are obtained by minimizing the pressure difference between the calculated and experimental data using the DE (Differential Evaluation) algorithm. A comparison is finally made between the presented model and the thermodynamic models based on the SRK and PR Eos.


Sunday, 26.06.2011

POSTER SESSION 2


PII-1. Thermodynamic properties, vaporization processes and modeling of ternary borosilicate melts

Stolyarova V.L.

Saint Petersburg State University

[email protected]

Study of high temperature behaviour of ternary borosilicate melts has the great importance for the development of the modern material science as well as for various technologies such as for the incorporation of nuclear wastes, for obtaining metals from slags in metallurgy, for preparation the special glasses:

- with low melting point; - with high refractive index; - with high dispersion coefficient; - with high radiotransparency; - with the effective absorbtion of the slow neutrons.

Information on the vaporization processes and thermodynamic properties of ternary borosilicate systems containing Na2O, Cs2O, Rb2O, MgO, CaO, SrO, BaO, PbO, ZnO and GeO2, obtained by high temperature mass spectrometric method in the temperature range 1100-2000 K was discussed. Various types of vapour species were found over ternary borosilicate melts studied such as the associated, dissociated and polymerized products of vaporization. It was shown that the content of vapour over these systems was in agreement with the composition of the gaseous phase over the corresponding binary systems. The regularities of the vaporization of corresponding binary and ternary systems according to the position of oxide modifier in the Periodic table of atoms were also illustrated and discussed from the point of view of the acid-base concept.

Results on determination of thermodynamic functions in ternary borosilicate systems mentioned were considered taking into account the main requirements for the confirmation of their reliability. Thermodynamic functions of these systems such as activities and chemical potentials of components as well as the Gibbs energies showed various signs of the deviations from the ideal behaviour.

For modeling of these thermodynamic properties of ternary borosilicate melts studied the general lattice theory of associated solutions was used. Based on this theory the correlation between thermodynamic functions obtained in the ternary borosilicate systems mentioned and the number of various types of bonds formed in these melts was illustrated. Using this approach the different levels of deviation from the ideality in the ternary borosilicate melts studied were clarified. The present study was done according to the financial support of the Russian Foundation for Basic Research according to Project N 10-03-705.


PII-2. Thermodynamic properties of melts in the PbO-B2O3-SiO2 and ZnO-B2O3-SiO2 systems: experimental study and

modeling

Stolyarova V.L., Lopatin S.I., Shilov A.L., Shugurov S.M.

Saint Petersburg State University

[email protected]

Processing of glass may be possible only in the cases when during vitrification the hazardous evaporation of its components at high temperatures may be prevented. For this purpose information on the vaporization processes and thermodynamic properties of melts as a function of temperature is required. First these data were obtained in the glass-forming melts in the PbO-B2O3-SiO2 and ZnO-B2O3-SiO2 systems containing heavy metals by the Knudsen effusion mass spectrometric method in the temperature range 900-1100 K. This study was carried out on the MS 1301 mass spectrometer developed for the investigation of the vaporization processes and thermodynamic properties of the low volatile substances. The installation was calibrated using cadmium as the standard. Vaporization was done from the double silica effusion cells. The PbO and ZnO activities in the melts studied were obtained by the ion current comparison method in the wide concentration ranges. Based on these data the B2O3, SiO2 activities and the Gibbs energies of formation were calculated. The significant negative deviations from the ideality were observed in the melts of the both systems studied.

The general lattice theory of the associated solutions was used for modeling of thermodynamic properties such as component activities, chemical potentials of components and Gibbs energies of borosilicate glass-forming melts containing PbO and ZnO. The agreement between calculated and experimental values of thermodynamic properties in the frame of the 15 % of the middle relative accuracy was illustrated. Based on this approach the relative numbers of bonds of various types when the second coordination sphere was taken into consideration were calculated. The correlation between the level of deviations from the ideality of thermodynamic functions in the ternary and corresponding binary melts studied and the changes of the relative numbers of these bonds as the function of concentration were shown. The present study was done according to the financial support of the Russian Foundation for Basic Research according to Project N 10-03-705.


PII-3. A Density Functional Approach to Adsorption of Oligomers on Chemically Bonded Phases

Borówko M., Staszewski T., Sokołowski S.

Maria Curie-Sklodowska University, Department for the Modelling of Physico-Chemical Processes

[email protected]

A density functional theory of adsorption of oligomers on surfaces modified with grafted chains (chemically bonded phases) is developed. The bonded phase is treated as a quasi-brush built of polymers anchored on the surface. The chain molecules are modeled as freely jointed spheres. Segments of all components interact with the solid surface via the hard-wall potential whereas interactions between all segments are described by Lennard-Jones (12-6) potential. The excess free energy due to hard-sphere interactions is calculated according to the fundamental measure theory of Rosenfeld [1]. The chain connectivity is described using the first-order theory of Wertheim [2]. The free energy resulting from attractive interactions is obtained within the mean field approximation. The approach is based on the theory developed by Yu and Wu [3]. The application of the density functional theory to grafted polymers was also discussed in our previous papers [5-4].

The structure of the brush and the behavior of adsorbed fluid are investigated. An influence of such parameters as the grafting density, the strengths of molecular interactions, the length of grafted chains and the sizes of adsorbed molecules on the structural and thermodynamical properties of the adsorbed fluid is analyzed. The primary, secondary and ternary adsorption of various molecules is discussed.

References [1] Y. Rosenfeld, Phys. Rev. Lett., 63 (1980) 980. [2] M.S. Wertheim, J. Chem. Phys., 87 (1987) 7372. [3] Y.X. Yu, J.J. Wu, J. Chem. Phys., 117 (2002) 2368. [4] M. Borówko, W. Rżysko, S. Sokołowski, T. Staszewski, J. Chem. Phys., 126 (2007) art. no. 214703. [5] M. Borówko, W. Rżysko, S. Sokołowski, T. Staszewski, J. Phys Chem. B 2009, 113, 4763.


PII-4. Adsorption from Binary Solutions on Chemically Bonded Phases - A Density Functional Study

Staszewski T., Borówko M., Sokołowski S.

Maria Curie-Sklodowska University, Department for the Modelling of Physico-Chemical Processes

[email protected]

A density functional theory is applied to study adsorption from binary solutions on chemically bonded phases. The liquid mixture consists of spherical molecules of different sizes. The bonded phase is built of polymers with end segments linked to the surface. The chain molecules are modeled as freely jointed spheres. Segments of the grafted polymers interact with the solid surface via the hard-wall potential. However, the free molecules are attracted by the wall (Lennard-Jones (9-3) potential). The Lennard-Jones (12-6) potential is used for modeling interactions between all spherical species. The approach is based on the theory developed by Yu and Wu [1] and our previous papers [2-3].

We discuss the role of grafting density, strengths of molecular interactions, the length of grafted chains and competitive adsorption from the solutions. The theoretical results are qualitatively compared with experimental data.

References [1] Y.X. Yu, J.J. Wu, J. Chem. Phys., 117 (2002) 2368. [2] M. Borówko, W. Rżysko, S. Sokołowski, T. Staszewski, J. Chem. Phys., 126 (2007) art. no. 214703. [3] M. Borówko, W. Rżysko, S. Sokołowski, T. Staszewski, J. Phys Chem. B 2009, 113, 4763.


PII-5. Nematic and Demixing Behaviour in Ternary Athermal Mixtures Formed by Uniaxial and Biaxial Hard Particles

Sokolova E.P., Marinichev A.N.

Department of Chemistry, St. Petersburg State University, Universitetskiy pr.,26, 198504, St. Petersburg, RUSSIA

[email protected]

Binary athermal fluid mixtures of hard prolate and platelike particles can exhibit the uniaxial rod-rich (N+) and plate-rich (N–) phases and the biaxial nematic (Nb) phase, characterized by the two mutually orthogonal direction of alignment of each component (compared to only one in uniaxial nematics) [1–4]. Most studies of the phase behaviour in systems of this kind have been carried out for two-component mixtures. Ternary fluids containing hard particles lacking an axis of rotational symmetry have not been addressed so far. Knowledge of properties of such systems may give an insight into the problems of stabilization of biaxial phases, and in understanding stability of colloidal suspensions due to doping with particles of the appropriate shape and form.

The present work is aimed at the study of the effect of changes in molecular shape and size of the adding component on the N+–N– demixing and on the formation of the Nb phase in a mixture of uniaxial rods and plates. Numerical calculations are performed using the off-lattice restricted orientation model of the nematic multi-component mixture of rectangular parallelepipeds with the D2h symmetry [5]. As shown in this study, the equation of state coincides with that obtained by other model approaches, such as the third-level y-expansion and a fundamental-measure theory for homogeneous phases [6].

The systems under consideration are modelled as mixtures composed of uniaxial rods (R) and plates (P) of size Li×Di×Di and biaxial particles (B) with dimensions L×B×W. Figure 1 shows the coexistence of the N+ and N– phases typical for R–P mixtures of particles with small aspect ratios. One also can see that the metastable B phase and the heterogeneous N+ –N– region are separated with a very small difference in the Gibbs free energy.

To locate the coexistence of the isotropic (I)–uniaxial (Nu) transition in ternary systems, the approach called the equal Gibbs energy analysis has been applied under the assumption that the corresponding two-phase regions are narrow. The representative lines of the I–Nu regions are obtained by setting equal the Gibbs potentials of the isotropic and the orientationally equilibrium Nu phases. Calculations have been carried out along the secants with the constant mole fraction ratios (yP / yR) of the platelets and rods. Results for yP / yR = 1 are shown in Figure 2; solid and dash lines divide N– (N+) and I regions in the cases of the biaxial particles with oblate (prolate) form. This result provides evidence that the R–P mixture under consideration may be stable to spinodal


decomposition into coexisting N+ and N– phases. The model under consideration can be identified as an idealized representation of the behaviour of the real ternary mixture of thermotropic mesogens [7] composed from prolate and oblate molecules which can be mixed using the so-called shape amphiphile formed from both rod-like and disk-like mesogenic units.

Figure 1. Phase diagram of the R–P mixture in the reduced temperature (t*) – composition frame.

Figure 2. Phase diagram between the component B and a 1:1 mixture of P (L/D=1/4) and R (L/D=5) in the t*–yB frame

Some numerical results are also presented which show the effect of introducing the third component with uniaxial molecules on enhancement of biaxial ordering against N+-N– demixing in the binary R–P system under study.

References [1] H.H. Wensink, G.J. Vroege, H.N.W. Lekkerkerker, Phys. Rev. E, (2002), 66, 041704-

(13). [2] Y. Martinéz-Ratón, J. A. Cuesta, J. Chem. Phys., (2003), 118, 10164-(10). [3] A. Galindo, A. J. Haslam, S. Varga, G. Jackson, A. G. Vanakaros, D. J. Photinos. D.

A. Dunmur, J. Chem. Phys., (2003), 119, 5216-(10). [4] R. Berardi, L. Muccioli, S. Orlandi, M. Ricci, C. Zannoni, J. Phys.: Condens. Matter,

(2008), 20, 463101-(16). [5] E. P. Sokolova, N. P. Tumanyan, A. Yu. Vlasov, A. J. Masters, Mol. Phys., (2006),

104, 2901-2917. [6] L. Harnau, D. Rowan, J.-P. Hansen, J. Chem. Phys., (2002), 117, 11359-(7). [7] R. W. Date, D. W. Bruce, J. Am. Chem. Soc., (2003), 125, 9012-9013.


PII-6. Vapor–Liquid Equilibrium in Diluted Polymer + Solvent Systems

Bogdanić G., Wichterle I.

Institute of Chemical Process Fundamentals of the ASCR, v. v. i., E. Hála Laboratory of Thermodynamics, Rozvojová 135, 165 02 Praha 6, Czech Republic

[email protected]

Vapor–liquid equilibrium data were determined for five polymer + toluene systems at isothermal conditions between 333.15 and 373.15 K. Polymers comprise copolymers and terpolymers of octadecyl acrylate (ODA), acrylic acid (AA), styrene (St), and 1-vinyl-2-pyrrolidone (VP) because of their practical importance as flow improvers for crude oil and/or derivatives. The need to measure these systems has emerged because relevant phase equilibrium data are not available in literature. All-glass micro-ebulliometer with circulation of liquid phase was used for measurement of total pressure over polymer + toluene mixtures, as described in our earlier study.1

To analyze the obtained data, we opted for the prediction of phase behavior, as the data of two experimental points, including concentration end points, could not be reduced with use of the UNIQUAC equation, as is e.g. in the Polymer Solution Data Collection by Hao et al.2 We used two predictive models, the Entropic-FV activity coefficient model3 and the GC-Flory EOS model,4 to estimate the activity of toluene in a mixture with a polymer. Both models are based on the group contribution method.

Two terpolymers, namely poly(ODA0.79–AA0.11–VP0.10) and poly(ODA0.82–St0.05–AA0.13) in mixtures with toluene were chosen as examples of solvent activity predictions, because values of all necessary group parameters for both models were at hand. Figures 1 and 2 show the prediction of toluene activities in both the terpolymer solutions, respectively. It is obvious that the models are mutually comparable and in a good agreement. Moreover, the dependence of solvent activity on concentration provides a qualitative description of particular system behavior over the whole concentration range including activity trends, since the prediction is based on group contributions, which comprises the structure of components involved. It is necessary to point out, that prediction procedures were not used for validation of experimental data, but to give an idea about the trend in activity vs. concentration dependence. As it can be seen, good agreement with experimental data was achieved.


Figure 1. Activity of toluene in Figure 2. Activity of toluene in poly(ODA0.82–St0.05–AA0.13) at 363.15 K. poly(ODA0.79–AA0.11–VP0.10) at 353.15 K.

experimental data; (····) predicted by the Entropic-FV model; (– – –) predicted by the GCFlory Model

References [1] J. Pavlíček, G. Bogdanić and I. Wichterle, Fluid Phase Equilib., 2010, 297 (1), 142–148. [2] W. Hao, H. S. Elbro and P. Alessi, Polymer Solution Data Collection. 1: Vapor–liquid Equilibrium, Chemistry Data Series XVI, Part 1, DECHEMA: Frankfurt/M., 1992. [3] G. M. Kontogeorgis, Aa. Fredenslund and D. P. Tassios, Ind. Eng. Chem. Res., 1993, 32 (2), 362–372. [4] G. Bogdanić and Aa. Fredenslund, Ind. Eng. Chem. Res. 1994, 33 (5), 1331–1340.


PII-7. Vapour–Liquid Equilibria in Alcohol + Hydrocarbon + Ketone Systems

Bernatová S., Pavlíček J., Wichterle I.

Institute of Chemical Process Fundamentals of the ASCR, v. v. i., E. Hála Laboratory of Thermodynamics, Rozvojová 135, 165 02 Praha 6, Czech Republic

[email protected]

New results of a continuing project dealing with phase equilibria in mixtures belonging to distinct families of organic compounds are reported in this presentation. Vapour–liquid equilibria were determined for binary subsystems and ternary systems containing alcohol, hydrocarbon and ketone, namely in the isobutanol (I) + 2,2,4-trimethylpentane (II) + 4-methyl-2-pentanone (III), and in the isopropylalcohol (IV) + 2,2,4-trimethylpentane + 2,4-dimethyl-3-pentanone (V) systems. All components involved have a common alkyl group [isopropyl (CH3)2CH– or tert-butyl (CH3)3C–], hydroxyl group OH–, and carbonyl group O=C=. The complete thermodynamic data (x–y–P–T) were determined at isothermal conditions. Azeotropic behaviour was found in the binary systems I+II, I+III, II+III, II+IV and in the I+II+III ternary system. The data reduction has been carried by the programme based on the maximum likelihood procedure1 which was modified by Pavlíček2. This new robust algorithm makes it possible to correlate vapour–liquid equilibrium isotherms or isobars together resulting in one set of universal parameters valid in the experimental pressure and temperature range. It can be applied to any correlation equation with temperature independent parameters such as e. g. the Wilson or NRTL equation. The consistency test by Van Ness3 proved a very good quality of data. Averaged standard deviations for all systems are 0.010, 0.006, 0.03 kPA, and 0.04 K for liquid phase composition (mole fraction), vapour phase composition (mole fraction), pressure and temperature, respectively. The experimental ternary data were compared with the data predicted using binary parameters. The absolute average deviations indicate that the Wilson equation predicts ternary data better than the NRTL one; generally, the results are very good. It should be pointed out that predictions need not necessarily reflect the quality of data. The experimental data are most likely better, because the imperfections of models also contribute to a certain “worsening” of calculated values. This is particularly applicable to the NRTL correlation. References [1] E. Hála, K. Aim, T. Boublík, J. Linek and I. Wichterle, Vapor–Liquid Equilibrium at Normal and Reduced Pressures (in Czech). Academia, Prague, 1982. [2] J. Pavlíček and I. Wichterle, Fluid Phase Equilib. 2007, 260, 70–73. [3] H. C. Van Ness, Pure Appl. Chem. 1995, 67, 859–872.


PII-8. Estimation of the porous structure parameters of the crosslinked macroporous poly(GMA-co-EGDMA).

1. Estimation of the specific pore volume

Bogdanić G.1, Jovanović S.M.2

1 - Institute of Chemical Process Fundamentals of the ASCR, v. v. i., E. Hála Laboratory of Thermodynamics, Rozvojová 135, 165 02 Praha 6, Czech Republic

2 - Faculty of Technology and Metallurgy, Karnegieva 4/IV, 11000 Belgrade, Serbia

[email protected]

New results of a project dealing with crosslinked macroporous poly(GMA-co-EGDMA) are reported in this presentation. Several macroporous crosslinked poly(GMA-co-EGDMA) have been synthesised earlier by the suspension copolymerization of glycidyl methacrylate (GMA) with ethylene glycol dimethacrylate (EGDMA) in presence of the inert component which contained 90 mass % of cyclohexanol [cy(CH2)5CHOH] and 10 mass % of six different aliphatic alcohols, such as butanol, octanol, decanol, dodecanol, tetradecanol and hexadecanol. Azobisisobutyronitrile was used as the initiator. Syntheses and copolymers characterisation was thoroughly described in references 1–3. The porosity parameters obtained from experiments [the specific surface area (Ss

exp), the specific pore volume (Vs

exp), the total open porosity (Pexp) and the pore diameter (dpexp)]

are summarized in Table 1. An interest in poly(GMA-co-EGDMA) copolymers has been raised since their properties can be adjusted to various application. Among other factors, the applicability is strongly dependent on their porosity. Due to that we tried to find out a way to predict the porous structure parameters. The attempt of this presentation is to illustrate the ability how to estimate the specific pore volume (Vs) based on van der Waals volumes by Bondi4,5 which may be considered as the best expression for different chemical groups occupancy. Estimated values of the specific pore volume (Vs

cal) and absolute deviations are shown in Table 1. It can be seen that in the so-called “first approximation” the specific pore volume of poly(GMA-co-EGDMA) copolymers may be predicted within an average mean deviation of 8.2 % only.


Table 1. Porous structure parameters of the investigated poly(GMA-co-EGDMA)

Copolymer Inert component in the feed

Ssexp

(m2/g) Vs

exp

(cm3/g) Pexp

(%) dp

exp

(nm) Vs

cal

(cm3/g) ∆Vs (%)

1 cy(CH2)5CHOH

+ CH3(CH2)3OH

70 0.58 41 44 0.57 1.7

2 cy(CH2)5CHOH

+ CH3(CH2)7OH

56 0.55 40 47 0.61 10.2

3 cy(CH2)5CHOH

+ CH3(CH2)9OH

53 0.56 40 48 0.62 11.4

4 cy(CH2)5CHOH

+ CH3(CH2)11OH

50 0.61 42 53 0.64 5.3

5 cy(CH2)5CHOH

+ CH3(CH2)13OH

47 0.74 47 68 0.66 10.8

6 cy(CH2)5CHOH

+ CH3(CH2)15OH

43 0.76 47 87 0.68 9.6

∆Vsaver (%) 8.2

References [1] S. M. Jovanović et al., Angew. Makrom. Chem., 1994, 219, 161–169. [2] S. M. Jovanović et al., Mater. Sci. Forum, 1996, 214, 155–162. [3] S. M. Jovanović et al., Hem. Ind., 2000, 54, 471–479. (in Engl.) [4] A. Bondi, J. Phys. Chem., 1964, 68, 441–451. [5] A. Bondi, Physical Properties of Molecular Crystals, Liquids and Glasses, Wiley, New York, 1968.


PII-9. Phase equilibria in binary mixtures of propane and phenanthrene: experimental data and modeling with the GC-

EoS

Breure B., Economou I.G., Vargas F.M., Peters C.J.

Chemical Engineering Department,The Petroleum Institute,P.O. Box 2533, Abu Dhabi, United Arab Emirates


Supercritical fluid extraction has proven to be a very useful and reliable separation technology. Besides the widely used extractants carbon dioxide and ethylene, also propane can be a suitable candidate as solvent for supercritical fluid applications.

In order to develop processes for the extraction of poly-aromatic compounds, such as naphthalene, acenaphthene and phenanthrene, with propane reliable phase equilibrium data are required to determine optimal regions for operation. If, in addition, the phase behavior of these aliphatic-poly-aromatic systems can be described accurately by an equation of state, design of the extraction process and its optimization can be greatly simplified.

Temperature

Pres

sure

Figure 1. Type III of fluid phase behavior in the classification of Scott and Van Konynenburg in the presence of a solid solute phase (B). Systems consisting of small volatile molecules, such as propane, and low volatile, complex molecules, such as poly-aromatic compounds, are known to show complex phase behavior. Multiphase fluid behavior can occur and also a solid phase may be present, which further increases the complexity of the phase diagrams. The present work focuses on binary mixtures consisting of propane + phenanthrene. This system shows type III phase behavior in the classification of Scott and Van Konynenburg1 (see Figure 1). Various two-phase and three-phase equilibria were measured experimentally, including equilbria in the presence of solid phenanthrene. Based on the course of the


different three-phase equilibria an estimation could be made for the location of the quadruple point solid phenanthrene-liquid-liquid-vapor.

The Group Contribution Equation of State (GC-EoS) developed by Skjold-Jørgensen2,3 was applied to reproduce the experimental data points. Phenanthrene was considered as a single group for which pure group parameters had to be determined by fitting phenanthrene vapor pressure data. Interaction parameters between phenanthrene and the CH3 and CH2 groups in propane were fitted to propane-phenanthrene bubble point data. The GC-EoS was applied to calculate vapor and liquid phase fugacities which were required in the phase equilibria calculations. The fugacity of pure solid phenanthrene was related to the fugacity of the pure subcooled liquid using changes in Gibbs free energy and a thermodynamic cycle which proceeds from the subcooled liquid to the solid state and passes through the triple point. Good agreement between experimental and calculated phase equilibrium data was obtained with the GC-EoS as is illustrated by Figure 2.

330 340 350 360 370 3800

1

2

3

4

5

6

7

SL2G

SL1L2

L1L2G

SL1Gp/

MPa

T/K Figure 2. p,T-diagram for the binary system propane-phenanthrene showing loci where three phases are in equilibrium. Comparison between predictions with the GC-EoS (lines) and experimental data (symbols). References [1] P.N. Van Konynenburg, R.L. Scott, Philosophical Transactions of the Royal Society, (1980), 298, 495-540. [2] S. Skjold-Jørgensen, Fluid Phase Equilibria, (1984), 16, 317-351. [3] S. Skjold-Jørgensen, Industrial and Engineering Chemistry Research, (1988), 27, 110-118.


PII-10. Experimental determination of diethyl methylphosphonate + CO2 and diethyl methylphosphonate +

CH4 phase equilibrium data

Mattea F.1, Peters C.J.2, Kroon M.C.3

1 - Laboratory for Process Equipment, Department of Process and Energy Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology,

Leeghwaterstraat 44, 2628 CA Delft, The Netherlands 2 - Petroleum Institute, Chemical Engineering Department Bu Hasa Building, Room 2203, Abu

Dhabi, United Arab Emirates 3 - Separation Technology Group, Department of Chemical Engineering and Chemistry,

Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands

[email protected]

Equations of state (EoS) that can be used as predictive tools are of great interest for many industrial applications. Group contribution equations of state, such as the GC-EoS developed by Skjold-Jørgensen [1], are useful to extend available experimental information of known systems to similar existing molecules or new molecules where no experimental information is available, but where the molecules share same functional groups. Many authors [2-4] have used the GC-EoS as a modeling tool and several functional groups have been added to the group database. However, new groups are necessary in the pursuit of new solvents. For example, the amine group was recently added to the GC-EoS [5], which required a modification of the GC-EoS by adding an associative term to account for the self-association of amines [6].

In this work, measurements of phosphonate based solvents are presented with the aim of providing the necessary phase equilibria data for a later inclusion of the phosphonate group into the GC-EoS database. For that purpose the solubility of carbon dioxide (CO2) and methane (CH4) in diethyl methylphosphonate (DEMP) was determined at different temperatures.

Very scarce information of phosphonate based solvents is available. As far as the authors know only the vapor pressure of several small alkyl phosphonates was measured by Butrow et al. [7] and the solubility of DEMP in CO2 was determined by Garach-Domech et al.[8]. In order to obtain the GC-EoS parameters for interactions with the phosphonate group, more experimental data of different solvents together with phosphonate-based molecules is necessary. In this work the phase behavior of the DEMP + CO2 system was measured and compared with the already published data. The phase behavior of the DEMP + CH4 system was also measured.

The synthetic method was employed in a Cailletet apparatus, a detailed description of the apparatus and the methodology can be found elsewhere [9]. Different concentrations of CO2 and CH4 in DEMP were assayed from temperatures ranging from 283.15 K to


363.15K, the results at a temperature of313.15 K are presented in Figure 1, also the pure vapor pressure of DEMP was included from [7] in this figure.

Figure 1. P-x diagram for (♦) CH4 – DEMP and () CO2 – DEMP Acknowledgements The authors thank the Institute for Sustainable Process Technology for the financial support and the Delft University of Technology for the laboratory facilities to perform the experiments.

References [1] S. Skjold-Jørgensen, Fluid Phase Eq., (1984), 16, 317-351. [2] T. Fornari, Fluid Phase Eq., (2007), 262, 187-209. [3] S. Espinosa, G.M. Foco, A. Bermudez, T. Fornari, (2000), 172, 129-143. [4] E. Kühne, A. Martin, G-J, Witkamp, C.J. Peters , Aiche J., (2009), 55, 1265-1273. [5] F.A. Sanchez, A.H. Mohammadi, A. Andreatta, S. Pereda, E. Brignole, D. Richon. Ind. Eng. Chem. Res., (2009), 48, 7705-7712. [6] H.P. Gross, S. Bottini, E. Brignole, Fluid Phase Eq.., (1996), 116, 537-544. [7] A.B. Butrow, J.H. Buchanan, D.E. Tevault, J. Chem. Eng. Data, (2009), 54, 1876-1883. [8] A. Garach-Domech, D. Rock, G. Sandhu, J. Russel, M.A. McHugh, B.K.. MacIver, J. Chem Eng. Data, (2002), 47, 984-986. [9] C.J. Peters, J.L. de Roo, J. de Swaan Arons, Fluid Phase Eq.., (1993), 85, 301-312.


PII-11. Prediction of Alcohol + Hydrocarbons Phase Equilibria by Monte Carlo Simulation. Application to an

Ethanoled Gasoline

Ferrando M.1,2, Lachet V.2, Boutin A.3

1 - Laboratoire de Chimie-Physique, UMR 8000 CNRS, Univ. Paris-Sud, 91405 Orsay, France 2 - IFP Energies nouvelles, 1-4 Avenue de Bois Preau, 92852 Rueil-Malmaison, France

3 - ENS, Chemistry Department, UPMC-CNRS, 75005 Paris, France

[email protected]

Due to recent regulations in the automobile industry related to the reduction of pollutants and greenhouses gases emissions, the use of oxygenated gasoline blends such as E10 to E85 (that is, containing 10 to 85% of ethanol) follows an exponential increase. The optimization of new flexi-fuel engines requires a good knowledge of physico-chemical properties of ethanol + gasoline mixtures. Therefore, accurate models are needed to predict the thermodynamic behaviour of such mixtures. Molecular simulation is becoming an efficient method that accurately describes thermodynamic properties of a wide variety of pure components and mixtures. In the present work, we propose to use such simulation techniques in order to determine bubble pressures and phase compositions of ethanol + gasoline blends, as a function of the ethanol content. Monte Carlo simulations are performed in a specific pseudo-ensemble which allows a direct calculation of the bubble pressure and phase properties of mixtures1,2. The AUA4 force field is used to model ethanol3 and hydrocarbon molecules4. The simulation of various binary mixtures (ethanol + n-hexane, ethanol + propene, ethanol + isooctane, ethanol + toluene) shows a good agreement between calculated and experimental vapour pressures and phase compositions, and the azeotrope of such binary mixtures is accurately predicted. Moreover, no empirical binary interaction coefficients are required, which shows the transferability of the force field and the predictive feature of the method. Then, we have predicted bubble pressures, coexistence densities and compositions of a typical gasoline modelled with 9 representative hydrocarbon molecules, at which various proportions of ethanol has been added (from 5 to 85% vol.). Simulations are found in good agreement with experiments. As expected, it is found that the bubble pressure is maximal for a specific ethanol content, as a consequence of the azeotropic behaviour of ethanol with hydrocarbons. This specific ethanol content increases with temperature.

References 1 Ungerer, P.; Boutin, A.; Fuchs, A. H. Mol. Phys., 1999, 97, 523-539 2 Ungerer, P.; Boutin, A.; Fuchs, A. H. Mol. Phys., 2001, 99, 1423-1434


3 Ferrando, N.; Lachet, V.; Teuler, J.M.; Boutin, A. J. Phys. Chem. B, 2009, 113, 5985-5995 4 Ungerer, P.; Tavitian, B.; Boutin, A. Applications of Molecular Simulation in the Oil and Gas Industry – Monte Carlo Methods, Ed. Technip, Paris, 2005


PII-12. Experimental and modeling investigations of some thermophysical properties of CO2 rich mixtures

Lachet V.1, Creton B.1, Le Roux D.1, Mougin P.1, Hy-Billiot J.2, Duchet-Suchaux P.2

1 - IFP Energies nouvelles 2 - TOTAL

[email protected]

In CCS (Carbon dioxide Capture and Storage) operations, the captured CO2 stream from industrial installations using the oxycombustion process is not a pure CO2: it contains some associated compounds, such as N2, O2, Ar, SO2, H2O... This mixture of gases may have significantly different thermo-physical properties as compared to a pure carbon dioxide. This may have impacts on the different stages of the CCS chain: capture, transportation, compression, injection and storage. For a global account of this impact and for a precise specification of maximal amounts of associated compounds that can be tolerated in CO2 flues, further investigations are strongly required. Obtaining accurate knowledge of the thermodynamic behaviour of CO2-associated gases mixtures is part of the studies that are necessary in order to develop optimized carbon dioxide capture and storage processes. In the present study, the thermodynamic behaviour and transport properties of some CO2 rich mixtures have been investigated using different complementary approaches: experimental measurements, molecular simulation and equation of state modeling.

First, vapour-liquid phase diagrams of several binary systems containing CO2 and/or associated compounds have been determined using the Gibbs Ensemble Monte Carlo method, that allows to compute phase equilibrium from an atomistic description of the system. The principle of this method is to generate successive configurations of the simulated system. On the basis of these simulations, appropriate statistical averages are performed to derive fluid properties that can be compared with experimental measurements. No calibration on experimental binary data have been performed for such calculations. Binary interaction parameters required by most classical cubic equations of state (Soave-Redlich-Kwong and Peng-Robinson) were then fitted to the obtained vapour-liquid equilibrium data.

Then, the densities and the viscosities of some CO2 rich mixtures were investigated using molecular dynamics simulations for temperatures ranging from 273.15 K to 333.15 K and pressures up to 20 MPa. Results were compared to measurements obtained with a vibrating tube densimeter and to pure carbon dioxide properties. Regarding these mixtures properties, a good agreement is obtained between simulated and experimental data. Comparisons with pure CO2 properties show that the presence of 8 mol. % of associated gases can lead to a decrease of the density and the viscosity of 15 % and 25 %, respectively. Then, the accuracy of standard correlative models, that are commonly used to estimate these different properties, have been studied.


In addition, hydrate dissociation temperatures of some CO2 rich mixtures containing small amounts of water have been studied. The precise knowledge of the conditions at which hydrates, in the absence of an aqueous phase, will be formed is required in order to optimise the CO2 stream dehydration process. In this study, hydrate dissociation temperatures were calculated using the classical van der Waals and Platteeuw hydrate model associated with the Cubic Plus Association equation of state to calculate the water fugacity in the CO2 rich phase.

Different water contents and different gas compositions have been investigated.


PII-13. Thermodynamic Parameters for the MIDA Interaction with Tungsten (VI) at Different Ionic Strengths

Majlesi K., Hajali N.

Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran, IRAN

[email protected]

Significant attention has been paid in our group to the study of the dioxovanadium (V), molybdenum(VI) and tungsten (VI) complexes at different ionic strengths including different solvents and comparisons of different models were also reported [1-6]. Interactions between the different components in a given system are a direct function of their activity coefficients and these depend on the ionic medium and ionic strength. Most experimental studies of chemical equilibria are performed according to the constant ionic medium method which means in the presence of an excess of an inert electrolyte (in this research it is sodium perchlorate). In this way, the activity coefficients of all the species are constant over a broad concentration range. Therefore results of an investigation on methyliminodiacetic acid (MIDA) interaction with WoO4

2- anion in NaClO4 aqueous solutions at different ionic strengths (0.1 to 1.0 mol.dm-3) at 25 ˚C are reported. Stability constants of only one species were determined on the basis of the Job method, UV spectrophotometric measurements and the corresponding dissociation constants by direct potentiometric titrations. The applicability of the Job method of continuous variations is discussed and justified for use in these studies. Data obtained were used to provide an ionic strength scheme.

Recently, owing to the large use of the Specific Ion Interaction Theory (SIT), this approach has been adopted as a standard procedure for the extrapolation and correction of equilibrium constants to infinite dilution in the OECD-NEA thermochemical databases and IUPAC project. Therefore in this research the difference in SIT parameters have been calculated. A modified SIT approach has also been proposed, where the specific interaction parameters are dependent on ionic strength. This is due to the fact that we need adding a term which takes into account the formation of weak (or even very weak) ion pairs. It was proposed that when the SIT approach is used for electrolyte concentrations less than 1 mol.dm -3, triple interactions or same charge ion interactions are generally negligible and apparently this is true for our research. Deviations from the Debye-Hückel equation could be due to a term linear in ionic strength, ion association or both phenomena taken together but it was found that in this work we have non-ideality in the absence of association. The parabolic model has also been applied to the dependence of metal complex formation and dissociation constants on ionic strength in this research. The parabolic model with two coefficients because of its advantages in mathematical simplicity and its less- parameterized nature is comparable to the Pitzer model in many cases. Finally the data fit with the Debye-Hückel ( on the basis of the errors for C and D ) and errors for the SIT and parabolic


models shows that parabolic model is the best one and SIT and Debye-Hückel models are in the second and third places respectively. References [1] K. Majlesi, S. Rezaienejad, J. Chem. Eng. Data, (2010), 55, 4491-4498. [2] K. Majlesi, S. Rezaienejad, J. Chem. Eng. Data, (2010), 55, 882-888. [3] K. Majlesi, M. Gholamhosseinzadeh, S. Rezaienejad, J. Solution. Chem, (2010), 39, 665-679. [4] K. Majlesi, S. Rezaienejad, J. Chem. Eng. Data, (2009), 54, 1483-1492. [5] K. Majlesi, N. Momeni, J. Chem. Eng. Data, (2009), 54, 2479-2482. [6] K. Majlesi, K. Zare, S. Rezaienejad, J. Chem. Eng. Data, (2008), 53, 2333-2340.


PII-14. Analogous Thermodynamic Prediction of Adsorption Excesses and Surface Tensions by Excess Quantities

Kalies G.1, Reichenbach C.1, Braeuer P.1, Enke D.2

1 - University of Leipzig, Institute of Experimental Physics I, Leipzig, Germany 2 - University of Leipzig, Institute of Chemical Technology, Leipzig, Germany

[email protected]

A new method based on measurable binary excess quantities was suggested for predicting ternary or higher-order adsorption excess data in [1]. Later, the prediction of adsorption equilibria could be improved by combining the Gibbs excess formalism with geometrical models [2]. This concerns both adsorption excesses at the liquid/solid interface as well as surface tensions at the liquid/air interface.

In this work, we present an extensive theoretical study concerning the analogous thermodynamic treatment of adsorption excess quantities at the liquid/solid and liquid/air interfaces. It is less the purpose to present new thermodynamic surface tension models than to show that the Gibbs excess formalism combined with geometrical models is universally applicable.

Figure 1. Adsorption excess of cyclohexane from the ternary liquid mixture on activated carbon at 303 K. Left: experimental, right: predicted [2].

References [1] G. Kalies, P. Bräuer, U. Messow, J. Colloid Interface Sci., (2004), 275, 410-418. [2] G. Kalies, C. Reichenbach, R. Rockmann, D. Enke, P. Bräuer, M. Jaroniec, J. Colloid Interface Sci. (2010), 352, 504-511.

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0cyclohexane ethyl acetate

benzene benzene

cyclohexane0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

ethyl acetate

-1.3-1.2-1.0-0.8-0.6-0.4-0.2-0.10.00.1


PII-15. Analytical Integration of the Gibbs Free Wetting Enthalpy for the Adsorption of Binary Liquid Mixtures on

Solids

Braeuer P., Kalies G.

University of Leipzig, Institute of Experimental Physics I, Leipzig, Germany

[email protected]

For the thermodynamic prediction of ternary or higher-order adsorption excess data from binary ones, the Gibbs free wetting enthalpies ij∆Φ of all three constituent binary liquid mixtures have to be calculated.

ij∆Φ [1, 2] can be obtained from the measured binary ,( )ij njΓ adsorption excess isotherm

and the bulk phase properties of a given binary liquid mixture (presented e.g. by the activity coefficients ln ij

jf of component j in the mixture) as follows:

( ) ( )( )( )

0 ,

ln1 d ;

1

, .; 1, 2; 2,3; .

ijjij ij x ij n ijij

j i j j

T P

x fRT RT

p T const i j i j

ξ

ξ

ξ ∂ξ ξ

ξ ξ ∂ ξ

=∗

=

Φ − Φ Γ∆Φ = = − + − = = = ≠

∫ (1)

Up to now, ij∆Φ has been calculated by numerical integration of Eq. (1), after describing ( )ij n

jΓ by analytical functions [1, 2] such as the Bi-Langmuir (BL) function,

the Kind (KI) function or the Redlich-Kister (RK) polynomial and ln ijjf by RK. For

predicting ternary data, however, the numerical expressions of Eq. (1) have to be described once more analytically. In this way, two different mathematical procedures (analytical and numerical) are used, which can lead to additional errors and therefore to more erroneous predictions of ternary data.

In order to overcome this insufficiency, we chose in this work the direct analytical integration of Eq. (1) with ( )ij n

jΓ isotherms being again described by BL, KI or RK and

ln ijjf by RK. This is not only the more elegant way, but provides better results of

prediction. We illustrate this by comparison of experiments and predictions of four different binary liquid mixture/solid adsorption systems.

References [1] G. Kalies, P. Bräuer and U. Messow, J. Coll. & Interf. Sci., (1999), 214, 344-352. [2] G. Kalies, P. Bräuer and F. Rouquérol, J. Coll. & Interf. Sci., (2000), 229, 407-417.


PII-16. Present Status of the Group Contribution Methods UNIFAC and Modified UNIFAC (Dortmund). Revision and

Extension

Constantinescu D.G., Gmehling J.

Department of Industrial Chemistry, Institute for Pure and Applied Chemistry, Carl von Ossietzky University of Oldenburg D-26111 Oldenburg, GERMANY

[email protected]

The synthesis, design and optimization of separation processes require a reliable knowledge of the phase equilibrium behavior of the system to be separated.

In the case of missing experimental data, group contribution methods such as ASOG, UNIFAC, modified UNIFAC, PSRK, etc. can be successfully applied. Although the UNIFAC method is used world-wide, the method still shows some weaknesses leading to poor results for activity coefficients at infinite dilution, excess enthalpies and asymmetric systems.

To overcome the above mentioned weaknesses, the group contribution method modified UNIFAC (Dortmund) has been developed, which has become very popular in the past few decades and consequently has been integrated into most commercial process simulators. Due to an ongoing research work, supported by the members of UNIFAC consortium, the large range of applicability of this approach is being continuously extended and at the same time the reliability of modified UNIFAC (Dortmund) is steadily improved by the revision of the group interaction parameters using an enlarged data base.

All required data for fitting the model parameters are taken from the Dortmund Data Bank (DDB), where sophisticated software packages for fitting reliable model parameters are integrated.

One of the further development of Modified UNIFAC (Dortmund) was the introduction of several new main groups (e.g. mono- and dialkylated amides, furane, oxime, silane, anhydrides, aromatic groups, carbonates, epoxides, sulfones, acroleine, ionic liquids, ....). The introduction of the major part of the new groups was decided in cooperation with our consortium members. However, because of the lack of the data for new compounds, a large number of additional measurements of VLE, γ∞, hE, SLE and azeotropic data must be performed before in our laboratory.

In this paper the most recent status of the research work within the UNIFAC consortium is presented together with some typical results.


PII-17. Dortmund Data Bank (DDB) and the Integrated Program Package (DDBSP)

Gmehling J., Rarey J.

DDBST GmbH, Marie-Curie-Str. 10, 26129 Oldenburg, Germany

[email protected]

The work on the Dortmund Data Bank (DDB) was started in 1973. The main goal was the development of thermodynamic models for the prediction of the real mixture behavior (phase equilibria, excess properties). Since 1989 DDB and the Integrated Software Package are continuously updated and extended by DDBST GmbH in Oldenburg, Germany. DDB today comprises more than 4.6 Mio. data tupels for more than 35 000 compounds from more than 60 000 references. DDB contains a great part of data not available via the open literature (systematic measurements for the development of predictive models, private communications, confidential data from industry, BSc, MSc, diploma and PhD theses, … from all over the world). DDB grows by nearly 8 % per year. The data input is mainly done at DDBST GmbH with support from colleagues from China, Japan, Korea, Estonia, Russia, ..

The data quality is ensured by a number of different approaches (e.g. various graphical representations). Especially the development of estimation methods for pure component and mixture data leads to the identification of low quality or questionable data.

Predictive models developed using the DDB include:

- UNIFAC and mod. UNIFAC for sub-critical non-electrolyte mixtures - PSRK and VTPR equations of state for sub- and supercritical pure components and mixtures. Both models have been extended to cover also electrolyte solutions. - LIFAC for sub-critical electrolyte solutions. - COSMO-RS (Ol) - Pure component property estimation methods for normal boiling point, vapor pres-sure, critical data, … . - …

where the further development of the predictive thermodynamic models UNIFAC, modified UNIFAC and PSRK is supported by a consortium of more than 45 companies from all over the world.

The integrated DDB software package (DDBSP) contains highly developed process synthesis tools for fitting recommended model parameters simultaneously to a comprehensive data base, evaluation of existing model parameters prior to process simulation, the selection of suitable solvents for azeotropic or extractive distillation, extraction, absorption, ... , etc.


DDB and DDBSP are available on thousands of computers in chemical, petrochemical, pharmaceutical, ... industry, engineering companies and are intensively used for research and education by many universities worldwide.

In this contribution the present status of the Dortmund Data Bank and important applications of the integrated software package for process development should be shown. Extensive additional information can be found at www.ddbst.com.


PII-18. NIST ThermoData Engine: Expanding Implementation of the Dynamic Data Evaluation Concept to

Ternary Mixtures

Diky V., Chirico R.D., Muzny C.D., Kazakov A., Magee J.W., Kroenlein K., Abdulagatov I., Frenkel M.

Thermodynamics Research Center, National Institute of Standards and Technology, Boulder, USA

[email protected]

ThermoData Engine (TDE) is the principal component of the Global Information System in Thermodynamics (ThermoGlobe) developed by the Thermodynamics Research Center (TRC) at the U. S. National Institute of Standards and Technology (USA). TDE was designed as the first software implementation of the dynamic data evaluation concept: automated analysis of thermophysical and thermochemical data and generation of critically evaluated property values on demand. TDE is also used for validation of new experimental data on the basis of consistency or inconsistency with other thermodynamically related data and molecular structure. Other functionalities that involve automated data evaluation include experiment planning and product design. A new recently developed version of TDE expands implementation of the dynamic data evaluation concept to ternary mixtures.

TDE is data expert software that works on the premise of the analysis of the entire body of knowledge available to date and provides users with instant access to the experimental data on ternary mixtures, thereby eliminating labor-intensive literature searches. The variety of ways to represent ternary data in TDE has been reduced to a limited number that are the most convenient, facilitate visual representation, and allow efficient comparison of the data by the user. TDE also generates parameters of binary models that are used for calculation of the properties of ternary mixtures. The models supported at this time are single-property models and activity coefficient models covering VLE, LLE, SLE, activity coefficients, and excess enthalpy data. Single-property models are generated for density, viscosity, surface tension, and thermal conductivity. Comparison of models to experimental data provides a foundation for their mutual validation and reveals potential data errors or the need for a more advanced analysis. Major functional features of the TDE in application to ternary mixtures will be demonstrated by showing examples.


PII-19. A New Viscosity Data Correlation for Hydrogen Derived from Symbolic Regression

Muzny C.D., Huber M.L., Kazakov A., Frenkel M.

Thermophysical Properties Division, National Institute of Standards and Technology

[email protected]

Viscosity data for hydrogen are available over a wide range of both temperature and pressure covering the liquid, gas and super-critical fluid phases. Several attempts have been made to develop a correlation for these data. It was found to be challenging to reproduce the variation in viscosity over the entire data range. Except for very limited regions of phase space where the kinetic theory of gases is applicable, these correlations are generally created empirically and are quite complex. We will present a new approach based on symbolic regression for discovering a simpler empirical functional form that has comparable performance to the more complicated current correlations. The technique of symbolic regression allows for the exploration of functional forms for data fitting as a function of complexity and fitting accuracy and thus, by making trade-offs between simplicity and accuracy of fit, permits one to find relatively simple forms that fit the vast majority of data. This technique will be described and its application to the correlation of hydrogen viscosity data will be detailed. The final form chosen from symbolic regression is subsequently optimized using traditional non-linear optimization techniques. This optimized form will be presented and its performance relative to other correlations will be discussed. As part of this development, data quality analysis has been necessary to properly weight the historical data that were first taken in the early 1900s and continue to be reported today. A review of the various data sources and an estimate of each sources approximate overall uncertainty will be given. All data correlation performance analysis will be given relative to these weights. Future plans for further expansion of the use of symbolic regression for thermophysical property data fitting will be outlined.


PII-20. Modeling of the sage – supercritical CO2 extraction system at different temperatures

Mićić V.1, Macura R.2, Pejović B.1

1 - Faculty of Technology Zvornik University of East Sarajevo, Republic of Srpska, Bosnia and Herzegovina

2 - Faculty of Science University of Banja Luka, Republic of Srpska, Bosnia and Herzegovina

[email protected]

The classical procedures for separating active substances from plant material, such as steam distillation and extraction with organic solvents have serious drawbacks. The distillation procedure allows only the separation of volatile compounds (essential oils), which to a greater or lesser extent are transformed under the influence of the elevated temperature [1]. Organic solvents are insufficiently selective, so they dissolve some concomitant compounds along with the active substances [2]. For these reason supercritical fluid extraction (SFE) with supercritical carbon dioxide (CO2) has been recently investigated as an important alternative to classical procedures [3]. CO2 is the most widely used in SFE because it is simple to use, inexpensive, nonflammable, nontoxic, chemically stable, shows great affinity to volatile (lipophilic) compounds, and can be easily and completely removed from any extract [4]. The influence of temperature on SFE of sage was investigation in this paper.

Sage was grown in the region of municipality Berkovići, Eastern Herzegovina, Republic of Srpska, Bosnia and Herzegovina in 2009. SFE – CO2 was carried out with a laboratory – scale high pressure extraction plant (HPEP, Nova Swiss, Effretikon, Switzerland). The main parts and characteristics (manufacturer specification) of the plant were as follows: the diaphragm – type compressor (up to 1000 bar), extractor with an internal volume of 200 ml (pmax = 700bar), separator with internal volume of 200 ml (pmax = 250 bar), and maximum CO2 mass flow rate of approximately 5.7 kg/h. Sample of sage after mill and sieving using sieve has mean particle radius d = 0.22 mm. The mass of sage in the extractor was 60 g, pressure was 100 bar and CO2 flow rate was 3.23·10-3 kg/min. The temperature of extraction was the investigated value (313, 323 and 333K), and the total extraction time was 10 hours. Separator conditions were 15 bar and 25°C.

To avoid the evaluation of an internal diffusion time we used the modified Reverchon - Sesti - Osseo equation (it is modified by professor Tolić) [5]:

Y = 100·[ ]1 exp( )at b− +

where t is the extraction time (s), Y is the normalized extraction yield (%); a is a constant, b is the correction term.


Y = max

100yy

⋅

where y is the extraction yield after time t (g/100 g drug), ymax is the maximum extraction yield (g/100g drug).

This equation is based on the assumption that for a certain extraction system, ti could be approximated as a constant. Modified equations for calculating normalized yield of total extract at different temperatures are shown in table 1. Table 1. Modified equation for calculating normalized yield of total extract at different extraction temperatures

T (K) Modified equation

|r|

313 Y = 100[1-exp(-0.0045t – 0.3652)] 0,987 323 Y = 100[1-exp(-0.0053t – 0.4676)] 0,984 333 Y = 100[1-exp(-0.0048t – 0.1885)] 0,993

|r| is the correlation coefficient We concluded that this model approximates the experimental results very well in all cases, with coefficient of correlation from 0.984 to 0.993.

ACKNOWLEDGMENT The authors are thankful to Ministry of Science and Technology of Republic of Srpska for financial support. References [1] H. Sovova, The Journal of Supercritical Fluids (2005), 33, 35-52. [2] E. Reverchon, Flavor and Fragrance Journal (1992), 7, 227-230. [3] Y. Chen, M. Tang, The Journal of Supercritical Fluids, (2000), 18, 87-99. [4] M. Corazza, T. Takeuchi, M. Meireles, The Journal of Supercritical Fluids, (2008), 43, 447 – 459. [5] Ž. Lepojević, S. Milošević, A. Tolić, Z. Zeković, Thyme (Thymus vulgaris L) Compounds in SFE, 6th Conference on Supercritical Fluids and Their Applications, Maiori, Italy (9 -12 September 2001), 209-214.


PII-21. Solar cooling by absorption system: Dimensioning and numerical simulation

Grosu L.1, Dobrovicescu A.2, Untea A.2, Rochelle P.1

1 - Laboratoire Energétique, Mécanique et Electromagnétisme, University of Paris Ouest Nanterre La Défense, 50, rue de Sèvres, 92410 Ville d’Avray, France

2 - University Polytechnic of Bucharest, Faculty of Mechanics, 313, Splaiul Independentei, sector 6, 060042, Bucharest, Romania

[email protected]

Many current research orientations concern reducing pollution and the environmental impact of engine or inverse cycle systems. An important component of this pollution is due to the air-conditioning systems. In this context, the introduction of technologies which use renewable energies like heat source, presents a double advantage: to limit pollution and to reduce the fuel cost.

This work consists in dimensioning a solar cooling absorption system, using a bromide of lithium and water as solution and optimizing its operation.

This installation will produce cold water (and cool air) and possibly warm water for a receiving public establishment. After having carried out a traditional calculation of thermal losses, by using commercial software (TTH) we could consider the refrigerating power of the installation (production of cold water) (Table 1).

Table 1. Heat transfer coefficients of studied establishment obtained with TTH

element external wall internal wall floor pillar terrace U/W·m-2K-1 0.4198 1.0105 2.0359 2.3492 0.3728

The results of the dimensioning and the numerical simulation of the system obtained with Thermoptim and EES will be confronted. A parametric study will allow a wise choice of the various parameters in order to optimize the system operation (fig. 1). In addition of this, an exergetic study was carried out to supplement the thermodynamic analysis of the system.


31 32 33 34 35 36

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

tAb,Cd [C]

ηex

ηexAbηexAbηexCdηexCd

ηexEvηexEv

ηexGηexG

ηexEcηexEc

Figure 1. Exergetic efficiency versus absorber temperature

References [1] J. Castaing-Lasvignottes, O. Marc, et al. (2008). "Modélisation et simulation dynamique d’une machine frigorifique à absorption H2O/LiBr : Application Solaire." COFRET. Nantes. [2] X. Garcia Casals (2006). "Solar absorption cooling in Spain: Perspectives and outcomes from the simulation of recent installations." Renewable Energy 31(9): 1371-1389. [3] S. Gibout, J. Castaing-Lasvignottes, et al. (2005). "Modélisation en régime variable d’une machine frigorifique à absorption pour une application solaire." Revue Générale du Froid 1058. [4] L. Grosu (2000). "Contribution à l’optimisation thermodynamique et économique des machines à cycle inverse à deux et trois réservoirs de chaleur", thèse de doctorat soutenue le 19 octobre 2000, Institut National Polytechnique de Lorraine, Nancy [5] M. Kilic, O. Kaynakli (2007). "Second law-based thermodynamic analysis of water-lithium bromide absorption refrigeration system." Energy 32: 1505–1512 [6] D. S. Kim, C. A. Infante Ferreira (2008). "Solar refrigeration options - a state-of-the-art review." Int. J. Refrigeration 31: 3-15. [7] M. Pons (2008a). "Bases for second law analyses of solar-powered systems, Part 1: the exergy of solar radiation." 21st Int. Conf. on Efficiency, Cost, Optimization, Simulation & Environmental Impact of Energy Systems Cracow-Gliwice, Poland 1: 139-146.


PII-22. Density, viscosity and speed of sound of binary mixtures of 1-butyl-3-methylimidazolium hexafluorophosfate

+ methanol at different temperatures and atmospheric pressure

Tôrres R.B.1, Hoga H.E.2, Volpe P.L.O.2

1 - Departamento de Engenharia Química, Centro Universitário da FEI, Av. Humberto de Alencar Castelo Branco, 3972, 09850-901, São Bernardo do Campo, São Paulo, Brazil

2 - Departamento de Físico-Química, Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz, C.P. 6145, 13083-970, Campinas, São Paulo, Brazil

[email protected]

In the present work, density, viscosity and speed of sound of the solutions of 1-butyl-3-methylimidazolium hexafluorophosfate [BMIM][PF6] + methanol have been measured over the entire composition range at (293.15, 298.15, 303.15 and 308.15) K and atmospheric pressure. Both pure liquid and mixture viscosity were measured using a Stabinger viscosimeter (Anton Paar SVM 3000M). Density and speed of sound were measured using a commercial density and speed of sound measurement apparatus (Anton Paar DSA 5000 densimeter and speed of sound analyzer). Excess molar volume, deviation in viscosity and deviation in isentropic compressibility have been calculated from the data and fitted to the Redlich-Kister polynomial. For all properties, the values are negative over the entire composition range. Excess molar volume and deviation in isentropic compressibility decrease whereas deviation in viscosity increases with increasing in temperature. The results obtained are discussed in terms of intermolecular interactions, particularly hydrogen-bonding interactions between like and unlike molecules.


PII-23. Excess molar volume of acetonitrile + amine mixtures at several temperatures

Bittencourt S.S.1, Tôrres R.B.2

1 - Departamento de Engenharia Mecânica, Centro Universitário da FEI, Av. Humberto de Alencar Castelo Branco, 3972, 09850-901, São Bernardo do Campo, SP, Brazil

2 - Departamento de Engenharia Química, Centro Universitário da FEI, Av. Humberto de Alencar Castelo Branco, 3972, 09850-901, São Bernardo do Campo, SP, Brazil

[email protected]

As a continuation of our study involving volumetric properties containing acetonitrile and amines [1-2], in the present work, densities of binary mixture of acetonitrile + propylamine (PA), or + dipropylamine (DPA), or + n-butylamine (n-BA), or + tert-butylamine (t-BA), or + trietylamine (TEA) have been used to determine the excess molar volumes, as a function of composition at different temperatures and at atmospheric pressure. The studied temperatures were 293.15, 298.15, 303.15 and 308.15 K. Density measurements of liquid pure and mixtures were performed by means of vibrating-tube densimeter (Anton Paar, DMA 4500) which was calibrated with distilled water and air. Excess molar volumes (VE) were calculated from the data and fit to the Redlich–Kister equation. VE is negative over the entire composition range for all investigated systems and the negative deviation follows the order: tert-butylamine > trietylamine > dipropylamine > propylamine > n-butylamine. For the (acetonitrile + n-butylamine), (acetonitrile + propylamine) and (acetonitrile + tert-butilamine) systems, excess molar volume decreases whereas for (acetonitrile + dipropylamine) and (acetonitrile + trietylamine) systems, excess volume increases with increasing in temperature of the mixtures. The experimental results are discussed in terms of intermolecular interactions, particularly hydrogen-bonding interactions between like and unlike molecules.

References [1] R.B. Tôrres, A.Z. Francesconi, Fluid Phase Equilibria, (2002), 200, 317-328. [2] R.B. Tôrres, A.Z. Francesconi, Journal of Molecular Liquids, (2003), 103, 99-110.


PII-24. High-pressure density of binary mixtures of methyl tert-butyl ether + alcohols

Hauk D.B.1, Tôrres R.B.2

1 - Departamento de Engenharia Mecânica, Centro Universitário da FEI, Av. Humberto de Alencar Castelo Branco, 3972, 09850-901, São Bernardo do Campo, SP, Brazil

2 - Departamento de Engenharia Química, Centro Universitário da FEI, Av. Humberto de Alencar Castelo Branco, 3972, 09850-901, São Bernardo do Campo, SP, Brazil

[email protected]

As a continuation of our study involving volumetric properties containing methyl tert-butyl ether (MTBE) and alcohol [1], in the present work, densities of binary mixture of MTBE + methanol, or + 1-propanol, or + butanol have been used to determine the excess molar volumes, as a function of composition at 298.15 K in a pressure range from (1 to 35) MPa. Both pure liquid and mixture densities were measured using a vibrating tube Anton Paar DMA 4500 densimeter, connected to an external Anton Paar HP high-pressure measuring cell, which enables density measurements up to 70 MPa. Excess molar volumes (VE) were calculated from the data and fit to the Redlich–Kister equation. VE is negative over the entire composition range for all investigated systems and the negative deviation follows the order: butanol > 1-propanol > methanol. For all studied systems, excess molar volume decreases with increasing in pressure of the mixtures. The results obtained are discussed in terms of intermolecular interactions, particularly hydrogen-bonding interactions between like and unlike molecules.

References [1] H.E. Hoga, R.B. Tôrres, J. Chem. Thermodynam., accepted for publication.


PII-25. Viscosity and Transport Properties of Ionic Liquids

Ignatiev N.V.1, Willner H.2, Bernhardt E.2, Barthen P.3

1 - Merck KGaA, PM-ABE, Darmstadt, D-64293, Germany 2 - Bergische Universität Wuppertal, Anorganische Chemie Gaußstr.20, D-47097 Wuppertal,

Germany 3 - Heinrich-Heine Universität, Institut für Anorganische Chemie und Strukturchemie II, D-

40225 Düsseldorf

[email protected]

Ionic liquids (ILs) attract considerable interest as new materials for different kind of applications, for instance: new media for chemical reactions [1,2], engineering fluids (lubricants, heat transfer materials), liquid media for separation and extraction technologies, additives, etc.. Due to their good electrical conductivity, ionic liquids can serve as electrolytes in various electrochemical devices or in electrochemical processes [3]. Ionic liquids possess advantageous properties such as: negligible vapour pressure and high thermal, chemical and electrochemical stability. They are able to dissolve many organic and inorganic substances. Ionic liquids are non-flammable and are liquid over a wide temperature range, but they are more viscous than conventional organic solvents.

The high viscosity of Ionic Liquids results in low current response in electrochemical processes and slows down the kinetic of bimolecular reactions, controlled by diffusion. To understand the influence of structural parameters on the transport (diffusion) properties of ionic liquids we have modified the classical Stokes-Einstein equation as follows [4]:

ILη ⋅=⋅ ⋅ + ⋅ ⋅ + ⋅ ⋅A A A C C C A,C A,C A,C

k Tb D r b D r b D r

k - Boltzmann constant; T – absolute temperature η - dynamic viscosity; r - radius of the anion, cation or ion-pair (cation + anion) DA – self-diffusion coefficient of anion; DC – self-diffusion coefficient of cation DA,C – self-diffusion coefficient of ion-pair bA = nA·4.5 π [5]; bB = nB·3.5 π [5]; bA,C = nA,C·6.0 π n = transference number The viscosity of ionic liquids strongly depends on the self-dissociation (ionicity [6]) rate of the ion-pairs (clusters) into free anions and cations which can move more or less independently from each other. Combination of weakly coordinating anions and organic cations with well delocalized positive charge results in the formation of room temperature ionic liquids possessing low viscosity. This phenomenon will be discussed on the examples of ionic liquids with perfluoroalkylfluorophospates and cyanofluoroborates anions (see Table). The van der Waals radius and mass of the anion


and cation are other parameters which influence the viscosity of ionic liquids. Change of the viscosities of ionic liquids by deuteration will be discussed.

Viscosity of ionic liquids strongly depends on the temperature. It seams that at high temperature (> 350 K) viscosity of ionic liquids is defined by the mobility (diffusivity) of the cations and anions only. At this critical conditions (full dissociation) the dependence of the ILs viscosity from the anion or cation size becomes insignificant by the reason that DA·rA (or DC·rC) remains practically constant at certain temperature. This phenomenon will be demonstrated and discussed on several examples.

Table

Cation Anion t, °C Density, g/cm3

Viscosity, mPa·s

[BF4]− 25 1.28 37

[BF3(CN)]−

20 40 60 80

1.19 1.17 1.16 1.14

14.7 9.2 6.3 4.6

[BF2(CN)2]−

20 40 60 80

1.12 1.10 1.09 1.08

11.1 7.1 4.9 3.7

[BF(CN)3]−

20 40 60 80

1.07 1.06 1.04 1.03

12.6 7.5 5.0 3.6

EMIM [B(CN)4]−

20 40 60 80

1.04 1.03 1.01 1.00

22.2 11.2 6.8 4.5

References 1. P. Wasserscheid, T. Welton (Eds.), Ionic Liquids in Synthesis, Second Edition, WILEY-VCH, Weinheim, 2008. 2. C. Chiappe, D. Pieraccini, J. Phys. Org. Chem. 18 (2005), 275-297. 3. H. Ohno (Ed.), Electrochemical Aspects of Ionic Liquids, WILEY-Interscience, 2005. 4. N. V. Ignatiev, A. Kucheryna, G. Bissky, H. Willner, “How to make ionic liquids more liquid”, in: J. F. Brennecke, R. D. Rodgers and K. R. Seddon (Ed.), Ionic liquids IV, ACS Symposium Series 975, Washington DC, 2007, pp. 320-334. 5. H. Tokuda, K. Hayamizu, K. Ishii, Md. A. H. Susan, M. Watanabe, J. Phys. Chem. B 108 (2004), 16593-16600. 6. K. Ueno, H. Tokuda, M. Watanabe, Phys. Chem. Chem. Phys., 12 (2010), 1649-1658.


PII-26. Phase behavior of 1-alkyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide and carbon dioxide

Park Y.K., Hwang S.Y., Park K.

Hongik University

[email protected]

Owing to their unique properties, such as negligible vapor pressure, thermal stability, and good ionic conductivity, ionic liquids have been employed in various areas. In particular, the usage of ionic liquid in the presence of carbon dioxide brought lots of attention to the scientific community. In this study, the phase behavior of the binary system of 1-alkyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide + CO2 was determined in the temperature range of 288 – 323 K with CO2 mole fraction ranging from 0.1 to 0.8. A high-pressure variable-volume view cell was used to carry out this experiment. The Peng-Robinson equation of state along with two-parameter mixing rule has been employed to correlate the experimental data. The effect of steric factor in the cation in the ionic liquid is shown to be very important on the CO2 solubility.


PII-27. Hybridizing SAFT and cubic EOS: what can be achieved?

Polishuk I.

Department of Chemical Engineering & Biotechnology, Ariel University Center of Samaria, 40700, Ariel, Israel

[email protected]

This study deals with creating a concept of the hybrid model gathering the advantages of both cubic EOS and SAFT approaches. The proposed idea is revision of the Chapman's et al. SAFT [1] by addressing the problem of the numerical pitfalls and the issue of the space available for dispersive interactions with further attaching the SAFT part by the cubic EOS's cohesive term. It is demonstrated that the resulting model on one hand preserves the characteristic for SAFT accuracy in estimating the liquid compressibility, and on the other one – the characteristic for cubic equations capability of simultaneous modeling of critical and sub-critical data. Moreover, on the basis of the comprehensive set of thermodynamic properties of 8 challenging for modeling compounds (including n-hexatriacontane, water and methanol) it has been demonstrated that the proposed EOS has an over-all superiority comparing even to one of the most successful versions of SAFT, namely the SAFT-VR-Mie. These results indicate that tracking the trends established by experimental data and using the century-long experience with developing semi-empirical engineering models might sometimes be preferred over the exclusive relying on advanced molecular theories.


W(m/s)1100 1400 1700 20000

400

800

1200

1600

P(bar)

Figure 1. Sound velocities of liquid n-hexatriacontane. Experimental data [2]: – 373.15 K, – 383.15 K, – 393.15 K, – 403.15 K. Solid lines – the proposed EOS, dashed lines – SAFT-VR-Mie [3] , dot-dashed lines – Peng-Robinson EOS. References [1] W. G. Chapman, K. E. Gubbins, G. Jackson and M. Radosz, Ind. Eng. Chem. Res., (1990), 29, 1709-1721. [2] S. Dutour, B. Lagourette and J. L. Daridon, J. Chem. Thermod. (2002), 34, 475-484. [3] T. Lafitte, D. Bessières, M. M. Piñeiro and J.-L. Daridon, J. Chem. Phys. (2006), 124, 024509-1-024509-16.


PII-28. Global Gibbs free energy minimization and phase stability analysis in multicomponent systems using harmony

search

Bonilla-Petriciolet A., Soto-Bernal J.J., Rosales-Candelas I.

Instituto Tecnológico de Aguascalientes, México

[email protected]

The modeling of phase equilibrium in multicomponent systems is essential in the design, operation, optimization and control of separation schemes. Specifically, the correct determination of phase behavior of multicomponent systems has a significant impact in several issues of process design including the determination of the equipment and energy costs of separation and purification strategies [1]. Therefore, the application of reliable method for phase equilibrium calculations is crucial for process system engineering. Phase stability and equilibrium calculations are challenging global optimization problems because the objective functions involved in these computations are non-convex, highly non-linear with several decision variables, and often have unfavorable attributes such as discontinuity and non-differentiability. Under these conditions, traditional optimization methods are not suitable for solving phase equilibrium problems. In particular, stochastic optimization methods are reliable and effective for phase equilibrium calculations in multicomponent systems. In fact, the study of stochastic optimization methods for phase equilibrium calculations has become an active research area in applied Thermodynamics and, to date, a number of stochastic methods have been studied and tested, e.g. [1-3]. These strategies usually show a robust performance in these thermodynamic calculations but, in some difficult problems, they may fail to locate the global optimal solution. Thus, alternative optimization strategies should be studied to identify a better approach for solving phase equilibrium problems.

Harmony Search (HS) is a novel stochastic optimization method, which has been conceptualized using the musical process of searching for a perfect state of harmony [4]. This optimization method is based on the analogy with music improvisation process where music players improvise the pitches of their instruments to obtain a better harmony. It is simpler both in formulation and computer implementation and may offer a better performance than other stochastic optimization methods such as genetic algorithms or particle swarm optimization. This study introduces the application of HS for phase stability and equilibrium calculations in multicomponent systems. In particular, the capabilities and limitations of the classical HS method (HSC) and two of its variants are analyzed and discussed. These variants are the Improved Harmony Search (IHS) and the Global-Best Harmony Search (GHS). In this study, several phase equilibrium problems from the literature have been used to assess the performance of these HS-based optimization methods. In summary, our results indicate that HS-based optimization methods are capable of handling the difficult characteristics of global


optimization problems for both phase stability and Gibbs free energy minimization in multicomponent systems. In particular, the Global-Best Harmony Search offers the best performance from the standpoint of algorithm reliability, whereas the classical Harmony Search method is the worst for performing the global optimization of objective functions involved in phase equilibrium calculations.

a)

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00HSCGHSIHS

*calf f− b)

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

0 250 500 750 1000 1250 1500 Number of improvisations / Harmony memory size

Figure 1. Convergence profiles for solving the (a) phase stability and (b) equilibrium problems for the ternary system toluene + water + aniline at 298 K using HSC, GHS and IHS.

References [1] W.A. Wakeham and R.P. Stateva, Reviews in Chemical Engineering, (2004), 20, 1-56. [2] Y.S. Teh and G.P. Rangaiah, Chemical Engineering Research and Design, (2002), 80, 745-759. [3] G.P. Rangaiah, Fluid Phase Equilibria, (2001), 187-188, 83-109. [4] Z.W. Geem, J.H. Kim and G.V. Loganathan, Simulation, (2001), 76, 60-68.


PII-29. Phase equilibria modeling of aromatic hydrocarbon and phenol mixtures with water and alcohols using the GCA-

EoS

Sánchez F.A., Pereda S., Brignole E.A.

PLAPIQUI, Universidad Nacional del Sur - CONICET

[email protected]

The Group Contribution (GC) with Association Equation of State (GCA-EoS) [1-2] is the first EoS of the SAFT family that uses a GC approach of the Wertheim model[3-4]. It has been recently upgraded to deal with multiple associating and solvating groups simultaneously and a re-parameterizaion is being carried out. Accounting the association by a real GC approach was possible through the simplification of the radial distribution function to a value of one. This approach is successfully applied to determine the parameters for each associating group to represent a family of organic compounds independently of their alkyl chain. It greatly simplifies the extension of the model to multicomponent mixtures. Moreover, it reduces the number of equations to be solved in order to find each component non-associated fractions, which is a time demanding procedure.

In this work, GCA-EoS extension to aromatic hydrocarbons and phenols with water and alcohols is presented. These compounds are important in different industrial fields (textile, fine chemicals, pharmaceutical, petrochemicals, materials, etc.). Aromatic compounds are important in chemical synthesis and pharmaceutical processes due to their high reactivity. However, these compounds and their derivatives are used not only as raw material for chemical synthesis but also as solvents. On the other hand, BTEX (benzene, toluene, ethyl-benzene, xylene) are main products of the petrochemical industry and are an important fraction of the naphtha. Finally, the growing interest in biofuels and biorefineries design call for the development of thermodynamic tools able to predict phase equilibria in multicomponent-associating mixtures containing not only aromatic hydrocarbons but also phenols. The second generation biofuels encourage the processing of the lingo cellulosic fraction of biomass, which is formed by an extremely stable polymer of phenols. Figure 1 and 2 shows GCA-EoS correlation and predictions for the binary systems water+phenol (VLE) and heptane+phenol (LLE), respectively. Moreover, Figure 3 depicts GCA-EoS prediction for the ternary system water+phenol+benzene.

The initial goal of this work was to develop a model able to predict phase behaviour of fuel/biofuel blends. However, this GCA-EoS review is part of a broader project that is the development of a robust thermodynamic model to be integrated in biorefineries simulators. We look for a tool able to simultaneously predict vapour-liquid and liquid-liquid equilibria (VLE and LLE) required for new process exploration.


Figure 1. Vapor-liquid equilibria of the system water (1) + phenol (2). Experimental data at ( ) 317, ( ) 333, ( ) 348 and ( ) 363 K. Dashed and solid lines: GCA-EoS correlation and prediction, respectively.

Figure 2. Vapor-liquid and liquid-liquid equilibria of the system n-heptane (1) + phenol (2) at 67 and 101 kPa. Lines: GCA-EoS predictions.

Figure 3. Liquid-liquid equilibria of the system water (1) + phenol (2) + benzene (3). Experimental data: symbols and solid tie lines. Dashed lines: GCA-EoS prediction. References

[1] M.S. Zabaloy, S.B. Bottini, E.A. Brignole, J. Chem. Eng. Data (1993), 38, 40-43. [2] H.P. Gros, S.B. Bottini, E.A. Brignole, Fluid Phase Equilibria(1996), 116, 537-544. [3] M.S. Wertheim, M.S., J.Stat. Phys. (1984), 35, 19-34. [4] M.S. Wertheim, J. Stat. Phys. (1984), 35, 35-47.


PII-30. The Critical Properties of Substances Estimated by The Artificial Neural Network Method

Bogatishcheva N.S., Nikitin E.D.

Institute of Thermal Physics, Ural Branch of the Russian Academy of Sciences, RUSSIA


Artificial neural networks have been used to determine the critical temperature and pressure of five homologous series with the common formula H(CH2)nR, where R stands for different end group: n-alkanes, 1-alkanols, 1-alkenes, alkanoic acids and n-alkylbenzenes. Experimental data are known only for the first several terms of the homologous series investigated by us. Chemical compounds with large molecular masses are thermally unstable, i.e. their thermal decomposition begins at temperatures lower than the critical temperature. This complicates the measurement of their critical properties. Interest in determination of the critical constants of thermally unstable compounds is caused by demands of practice: they are required for building up equations of state of both substances themselves and their mixtures, are used for calculating some other thermodynamic properties of chemical compounds with help of the principle of corresponding states.

A great number of different methods of calculating critical parameters of organic compounds have been suggested. The most popular ones are group-contribution methods and various means of extrapolation of experimental data obtained for the initial terms of a homologous serious to the subsequent terms. An analysis of the existing methods has shown that the most of them adequately describe experimental data for substances with small molecular masses and is doing so give bad results in the case of long-range extrapolation. Besides, the existing approximating equations are applicable for predicting critical properties of only well-investigated homologous series (for instance, n-alkanes).

In the present paper for the determination of critical parameters use is made of a two-layer feed-forward network. As is well-known, such a network can reproduce with an arbitrary accuracy any continuous function of many variables with a sufficient number of neurons of the hidden layer given.

To approximate a critical temperature, use was made of a two-layer neural network with three sigmoid neurons of the hidden layer and one linear neuron of the output layer. The training was carried out with the use of the Levenberg-Marquardt optimization algorithm with Bayesian regularization. A perceptron with hyperbolic tangent transfer functions in every layer was chosen for the approximation of a critical pressure. In this case use was made of a training function which modifies the values of weights and biases by the gradient descent method. All experimental data were divided into a


training set and a validation set in accordance with Table 1. Calculations were made with the help of the mathematical packet Matlab 7.4.

Neural networks have also been used to examine the limiting behavior of critical properties of substances consisting of chain molecules when the number of repeating units tends to infinity. As a result, it has been found that in this case the temperature has a finite value, and the critical pressure tends to zero.

The results of calculation have been compared with data obtained with the help of previously developed methods of determining the critical properties of substances consisting of chain molecules [1, 2]. The first method is based on the equation of state for a fluid of chain molecules. The second method uses hypothesis of functional self-similarity and the idea of the scaling behavior of critical constants of long chain molecules. A comparison of average percent deviations of the results of calculation from experimental data and analysis of the behavior of critical constants when the number of repeating units tends to infinity has made it possible to conclude that neural networks can be successfully used for determining critical parameters of substances that consist of chain molecules. However, the main drawback of the employment of neural networks for solving problems of extrapolation of the critical properties of substances is the lack of sufficient body of experimental data required for the training of a neural network, which makes the method unsuitable for a great number of chemical compounds.

Table 1. Homologous series studied.

number of carbons in a molecule homologous series training set Validation set n-alkanes 2-21 22-36 1-alkanols 1-15 16-22 1-alkenes 2-17 18-20

n-alkylbenzenes 6-14 16-19 alkanoic acids 2-16 17-21

The work was supported by a grant of the Ural Branch of RAS for the support of young scientists.

References [1] E.D. Nikitin, P.A. Pavlov, N.S. Bogatishcheva, Fluid Phase Equilib., (2005), 235, 1-6. [2] E.D. Nikitin, P.A. Pavlov, High Temp., (2000), 38, 690-697.


PII-31. Influence of Hydrophobic Tail Structure on Biological Activity of Soft Gemini Cationic Surfactants

Łuczyński J.1, Poźniak R.1, Bonarska-Kujawa D.2, Kleszczyńska H.2, Wilk K.1, Witek S.1

1 - Department of Chemistry, Wroclaw University of Technology, wyb. Wyspiańskiego 27, 50-370 Wroclaw, POLAND

2 - Department of Physics and Biophysics, Wroclaw University of Environmental and Life Science, Norwida 25, 50-375 Wroclaw, POLAND

[email protected]

The present work is a continuation of our previous research on synthesis and – mainly biological – properties of both monomeric and dimeric (gemini) esterquats. Such compounds as glycine or/and alanine derivatives were found as excellent inhibitors of ATPases [1] and MDR pumps [2] in yeast and interact with artificial and natural biological membranes [3].

A set of dimeric esterquats derivatives of glycine and alanine (structures of the compounds are given below) was synthesized and their biological properties were determined and presented.

A series of soft gemini bis-quaternary ammonium surfactants - derivatives of bis-glycine (bis-alanine) esters, were synthesized by quaternization of N,N,N’,N’-tetramethyl-ethylene (or propylene) diamine with n-alkyl chloroacetates or n-alkyl α-bromopropionates.

The research was carried out on pig erythrocytes and isolated membranes (ghosts), which were prepared by the Dodge method. The pig red blood membrane is known to be the closest to the human erythrocyte membrane with respect to its lipid composition.

The hemolysis were conducted on fresh blood, for washing the erythrocytes and in the experiments performed, an isotonic phosphate solution of pH 7.4 was used.

The erythrocytes were washed in a phosphate buffer and then incubated in the same solution but containing proper amounts of the compounds studied. The modification was conducted at 37oC for 1h. After modification samples were centrifuged and the supernatant


assayed for hemoglobin content using a spectrophotometer. Hemoglobin concentration in the supernatant, expressed as a percentage of hemoglobin concentration in the supernatant of totally hemolysed cells, was assumed as the measure of the extent of hemolysis.

Hemolytic studies showed that the compounds used incorporated into the erythrocytes membrane lipid phase, because of their amphiphilic character and induce hemolysis at the certain concentrations. The compound had showed high hemolytic activity depending on alkyl chains length.

The effect of studied compounds on fluidity and density of lipids in the erythrocyte membrane has been investigated using the fluorimetric method with different fluorescence probes. Fluidity of erythrocyte lipids in the hydrophobic region has been investigated with DPH probe and density of membrane lipids has been describe by general polarization (GP) of Laurdan probe.

Studied compounds used in below hemolytical concentrations determined changes in membrane fluidity and lipids arrangement in the hydrophilic part of membrane depended on structure of molecules. References [1] E. Obłąk, T.M. Lachowicz, J. Łuczyński, S. Witek, Cell. Mol. Biol. Lett., 7, (2002), 1121. [2] M. Kołaczkowski, A. Kołaczkowska, J. Łuczyński, S. Witek, A. Goffeau, Microb. Drug Resistance, 4, (1998), 143. [3] H. Kleszczyńska, J. Sarapuk, S. Przestalski, M. Kilian, Studia Biophysica, 135, (1990), 191.


PII-32. New Ionic Liquids Containing 3-Alkoxy-2-hydroxypropyl- Moiety

Poźniak R., Sokolowski A., Łuczyński J.

Department of Chemistry, Wroclaw University of Technology, wyb. Wyspiańskiego 27, 50-370 Wroclaw, POLAND

[email protected]

Introduction Ionic liquids (ILs) are defined as organic salts with melting points below 100oC, and whose melts are composed of discrete cations and anions [1]. Properties of ILs - such as density, melting point, viscosity, or solubility in water or other molecular solvents - can be fine-tuned by changing either the anion or cation [2].

In this study, we present the synthesis, antielectrostatic and surface active properties of novel ILs, derivatived from imidazole and morpholine.

N-(3-alkoxy-2-hydroxypropyl)-N’-methylimidazolium (a) and N-(3-alkoxy-2-hydroxy-propyl)-N-methylmorpholinium (b) tetrafluoroborates, hexafluorophosphates and methylsulfates:

R = n-alkyl: C4, C5, C6, C8, C10, C12; A = BF4, PF6, CH3SO4

were prepared in three-step reactions. The first step is the preparation of N-(3-alkoxy-2-hydroxypropyl)imidazolines and N-(3-alkoxy-2-hydroxypropyl)morpholines from alkylglycidyl ethers and imidazole or morpholine. The second step is the quaternization reaction of obtained tertiary ones with methyl bromide or dimethyl sulfate. The third step is the metathesis of the bromide salts with KBF4 and NaPF6. The structures of the new ILs were established on the basis of their spectral properties and elementary analysis.

Antielectrostatic agents are substances that are added to textiles or plastic materials in order to reduce their propensity to accumulate electrostatic charges. The main groups of antielectrostatic agents include ionic compounds such as quaternary ammonium salts and amines. Antielectrostatic properties of the studied compounds were measured by means of surface resistance, Rs, the charge decay half-time, τ1/2, on polyethylene film and polypropylene nonwoven fabric, by a method described earlier [3].

A systematic study of adsorption properties of N-methylmorpholinium and N-methylimidazolium derivatives has been undertaken using surface tension


measurements. On the basis of the empirical adsorption isotherms, which not only reflect the correlation between the concentration of amphiphiles, x, and the surface pressure, π, but also the effect of the structural elements of the ionic liquids molecules on the adsorption process for the whole group of studied compounds, the surface excess concentration, Γπ, surface area demand per molecule, Aπ, critical micelle concentration, cmc, and standard free energy of adsorption, ∆G0

ads, are discussed. The obtained results reflect quantitatively the effect of intramolecular environment of ionic liquid molecules on its amphiphilic character.

Conclusions This investigation has shown that novel ionic liquids in the imidazolium and morpholinium family can be successfully prepared in high yields. This work shows that ionic liquids have antielectrostatic properties. The antielectrostatic effect of N-(3-alkoxy-2-hydroxypropyl)-N’-methylimidazolium salts depends on the substituents in the imidazole ring and the kind of anion. The most favorable alkyl in the alkoxy group contains 8-12 carbon atoms. Tetrafluoroborates are more effective than hexafluorophospates. The best results (excellent antielectrostatic effect) were obtained from N-(3-alkoxy-2-hydroxypropyl)-N’-methylimidazolium methylsulfates and N-(3-alkoxy-2-hydroxypropyl)-N-methylmorpholinium methylsulfates containing 8 and 10 carbon atoms in the alkyl chain. ILs containing 12 carbon atoms in the alkyl chain show very good antielectrostatic effect.

From adsorption data it is evident that ∆G0ads values are influenced not only by the

length of the alkyl chain R, but also by the size and amphiphilic character of imidazole and morpholine rings. Morpholine ring is much more hydrophobic than imidazole one; due to this, imidazolium salts exhibit much higher surface activity.

Above results indicate that both nature of the anionic and ring type of the cation significantly affected the effectiveness adsorption at air-water interface and correlated antistatic properties.

References [1] Ionic Liquids III A/B: Fundamentals, Progress, Challenges, and Opportunities, ed. R.D. Rogers, K.R. Seddon), ACS Symp. Ser. 901/902, American Chemical Society, Washington, DC, 2005. [2] M. Deetlefs, K. R. Seddon, M. Shara, New J. Chem., (2006), 30, 317–326. [3] J. Pernak, A. Czepukowicz, R. Poźniak, Ind. Eng. Chem. Res., (2001), 40, 2379–2383.


PII-33. Polyassociative model of solution & its application to p-T-x equilibria analysis in multicomponent semiconductor

systems

Moskvin P.P.1, Olchowik J.M.2, Olchowik G.2

1 - Zhytomyr State Technological University, 103 Chernyakhovsky str., Zhytomyr, 10005, Ukraine

2 - Institute of Physics, Lublin University of Technology, 38D Nadbystrzycka, Lublin 20-618, Poland

[email protected]

Data on phase equilibria, as a first approximation, form a basis at a choice of conditions of heterostructures formation on the basis of А2В6 multicomponent semiconductors and growth of magnetic solid solution with spinel structure. Heterostructures of the this type semiconductors are a main component of devices sensitive to electromagnetic radiation from IR to X-ray radiation and soft components of radiation. Also necessary to notice, the data about phase equilibria in systems allow to develop more informative kinetic models of crystallization of solid solutions.

The model of polyassociative solutions assumes presence set of associates of various compositions in melt of systems. Change of concentration of associates with different compositions in a liquid phase with change of temperature in system allows to describe difficult enough form of liquidus of these systems [1-3]. Insignificant concentration of free, not associative atoms of components in the melt allows to explain the insignificant partial pressure of components over own melt in these semiconductors [2-3].

Results of the present work for application of polyassociative solution model of liquid phase to description of p–T–x equilibria in ternary semiconductor systems Cd–Hg–Te [1], Zn–Cd–Te [2], their initial binary materials, and also in magnetic spinel Zn–Mn–Fe–O [3] are discussed and generalized. Features of phase diagrams of these systems are discussed and is proved, what only the polyassociative solution model is capable to describe well the phase equilibria phase in them. Recommendations for choice of associates which presence in a liquid phase is the most probable are developed. Features of search of thermodynamic parameters of model for systems are discussed. The mathematical difficulties arising by search of parameters of model are marked. Recommendations for overcoming of mathematical difficulties are developed at the decision of a problem of getting of temperature dependences of dissociation constants of liquid phase complexes.

Comparisons of calculations and experimental data on p–T–x equilibria in considered systems are executed. The reached conformity between them confirms applicability of polyassociative solution model for the description phase equilibria in A2B6 semiconductor systems and oxide magnetic solid solutions.


References [1] P. Moskvin, V. Khodakovsky, L. Rashkovetskii, A. Stronski, J. Crystal Growth, (2008), 310, 2617. [2] P. Moskvin, Russian J. Physical Chemistry, (2010) 84, 2010. [3] S. Linin, P. Moskvin, E. Pshenichnov, I. Saenko, Russian J. Physical Chemistry, (1992), 66, 2310.


PII-34. Simulis® Thermodynamics: a complete thermodynamic calculation server

Baudouin O., Déchelotte S., Vacher A.

ProSim

[email protected]

Simulis® is the name of ProSim’s software suite. The component-oriented approach of its architecture is based on the Microsoft®’s COM/DCOM middleware. Simulis® Thermodynamics, one of the first components, is a thermophysical calculation server that generates highly accurate pure component and mixture properties (thermodynamic, transport, compressibility…) and fluid phase equilibria (liquid-vapor, liquid-liquid and liquid-liquid-vapor). Thermodynamic package integrates a pure component database, based on the DIPPR database and several thermodynamics models: equations of state, activity coefficient models, specific models... The thermodynamic library is enriched every year. For example, recently, the PPC-SAFT model developed by LIMHP and IFP [1-4] and NRTL-PR model developed by Pr. Neau et al. [5-7] were implemented.

The standard version of Simulis® Thermodynamics is provided as an add-in in Microsoft® Excel or as a toolbox in MATLAB® and enables the user to run complete thermodynamic calculations in these applications, but it can also be plugged in any legacy code using the SDK (Software Development Kit). One main benefit of Simulis® Thermodynamics is its CAPE-OPEN [8] compliance through its implementation of the CAPE-OPEN standardized interfaces: “thermodynamic plug” and “thermodynamic socket”. Another main benefit is the capability to embed legacy codes either as a DLL (Dynamic Link Library) following a standard syntax, either as VBScript (Visual Basic Script) directly written from the Simulis® Thermodynamics’ environment. Then, the user code inherits of all the features of Simulis® Thermodynamics: CAPE-OPEN compliance, Microsoft® Excel add-in, MATLAB® toolbox…

References [1] D. Nguyen Huynh , A. Falaix, J.P. Passarello, P. Tobaly, J.C. de Hemptinne, Fluid Phase Equilibria, 264 (1), 184-200 (2008) [2] D. Nguyen Huynh , J.P. Passarello, P. Tobaly, J.C. de Hemptinne, Fluid Phase Equilibria, 264 (1-2), 62-75 (2008) [3] D. Nguyen Huynh , J.P. Passarello, P. Tobaly, J.C. de Hemptinne, Industrial & Engineering Chemistry Research 47 (22), 8847-8858 (2008) [4] D. Nguyen Huynh , J.P. Passarello, P. Tobaly, J.C. de Hemptinne, Industrial & Engineering Chemistry Research 47 (22), 8859-8868 (2008) [5] J. Escandell, “Mise au point d’une méthode predictive pour le calcul des équilibres de phases des systèmes eau – hydrocarbures – glycols”, phD Thesis, (2008).


[6] E. Neau, J. Escandell, C. Nicolas, “Modeling of highly nonideal systems: 1. A generalized version of the NRTL equation for the description of low-pressure equilibria”, Ind. Eng. Chem. Res., 49, pp. 7580-7588 (2010) [7] E. Neau, J. Escandell, C. Nicolas, “Modeling of highly nonideal systems: 2. Prediction of high pressure phase equilibria with the groupe contribution NRTL-PR-EoS”, Ind. Eng. Chem. Res., 49, pp. 7589-7596 (2010) [8] The CAPE-OPEN Laboratories Network, http://www.co-lan.org/Dissemination.html


PII-35. Solubility of nonsteroidal anti-inflammatory drugs in supercritical carbon dioxide

Montes A., Gordillo D., Pereyra C.

University of Cadiz, Spain

[email protected]

The experimental solubility of naproxen and ibuprofen, two nonsteroidal anti-inflammatory drugs (NSAIDs), in supercritical carbon dioxide (SC-CO2) has been determined by a dynamic method in the pressure range 100-350 bar and the temperature range 313 to 353 K. The apparatus used in this work was especially designed in our laboratories in order to measure solubility and it has been used to measure the solubility of different solutes [1-3]. The flow diagram of the installation is shown in Figure 1. Naproxen and ibuprofen are two of the most widely prescribed NSAIDs.

The interest in the Supercritical Fluid Technology lies in the possibility to precipitate these drugs by rapid expansion of supercritical solutions (RESS) process. Carbon dioxide is the most commonly used supercritical fluid to its nontoxic, non-flammable, environmental friendly properties and mild supercritical conditions. The RESS process is a process for the production of small and uniform microparticles. It can lead to solvent-free, drug-loaded polymer microspheres for controlled drug release of therapeutic agents. In the RESS method, the sudden expansion of a supercritical solution (CO2-drug system) via nozzle in an atmospheric chamber and the rapid phase change at the exit of the nozzle causes a high super-saturation and pure particles in micron and submicron level can be obtained [4].

The application of the Supercritical Fluid Technology in precipitation processes takes implicit the study of the phase equilibrium formed by each one of the solutes and the supercritical solvent, that is to say, the fluid-solid phase equilibrium.

The solubility data have been correlated by cubic equations of state and empirical equations using different group contribution methods to estimate critical properties of both solutes.


Figure 1. Schematic diagram of the experimental apparatus: (1) gas tank; (2) constant temperature bath; (3) check valve; (4) pressure regulating valve; (5) liquid pump; (6) preheater; (7) rupture disc; (8) equilibrium cell; (9) pressure gauge; (10) metering valve; (11) cold traps; (12) volumetric flow meter. References [1] M.D. Gordillo, M.A. Blanco, A. Molero and E. Martinez de la Ossa, Journal of Supercritical Fluids, (1999), 15 (3), 183-190. [2] M.D. Gordillo, C. Pereyra and E.J. Martínez de la Ossa, Journal of Supercritical Fluids, (2003), 27 (1), 31-37. [3] M.D. Gordillo, M.A. Blanco, C. Pereyra and E.J. Martínez de la Ossa, Computers and Chemical Engineering, (2005), 29 (9), 1885-1890. [4] A. Zeinolabedini and F. Esmaeilzadeh, Journal of Supercritical Fluids, (2010), 52 (1), 84-98.


PII-36. Research Progresses of Ionic Liquids as Absorption Cycle Working Fluids

Zheng D., Dong L., Wu X., Li J., Sun G.

Beijing University of Chemical Technology, China

[email protected]

In recent years, some researchers proposed that ionic liquids (ILs) as alternative absorbent-species combined with refrigerants such as water, ammonia, alcohols, hydrofluorocarbons(HFCs) can be used for the absorption refrigeration cycle. Primarily on the basis of author's work, the aim of this paper is to present the selection of alternative working pairs, thermophysical property measurement and modeling of new working pairs, and the research progresses of the absorption cycle performance assessment on the basis of these working fluids.

Table 1. Assessment plan for the absorption working pairs containing ILs Traditional working pairs New working pairs Binary system Ternary systems H2O-LiBr H2O-ILs H2O-LiBr-ILs NH3-H2O NH3-ILs NH3-H2O-ILs HFC-absorbent HFC-ILs —

Table 2. Available VLE data and prediction plan for HFC-IL combinations HFCs R134a R143a R134 R152a R32 R23 R41 R161 R125 [Emim][BF4] ? ? ? ? ? ? ? ? [Bmim][BF4] ? ? ? ? ? ? ? [Hmim][BF4] ? ? ? ? ? ? ? [Emim][PF6] ? ? ? ? ? ? ? ? ? [Bmim][PF6] [Hmim][PF6] ? ? ? ? ? ? ? ? [Emim][Tf2N] ? ? ? ? ? ? [Bmim][Tf2N] ? ? ? ? ? ? ? ? [Hmim][Tf2N] ? ? ? ? ? ? ? [Emim][CF3SO3] ? [Bmim][CF3SO3] ? [Hmim][CF3SO3] ? ? ?

Some alternative working pairs were selected, through investigating the interacting regulation and the affinity between ILs and refrigerants and evaluating the absorption potential, i.e. the extremum value of the excess Gibbs function and the activity coefficient in dilute solution, which can be obtained either from solubility experimental data or by UNIFAC prediction model.


The vapor pressure, heat capacity, and density of the system were measured, and the thermodynamic models were correlated correspondingly for several H2O-IL systems. The performance characteristics of the investigated working pairs in terms of the cycle performance were calculated for a single-stage absorption cycle. The comparison with other H2O-IL systems shows that some promising systems have the potential to be developed further.

On the other hand, focusing on the drawbacks of traditional working fluids H2O-LiBr and NH3-H2O, the research results show that adding ILs to the H2O-LiBr can increase solubility and improve the crystallization characteristic, and adding ILs in NH3-H2O can facilitate separation of ammonia and reduce the renewable energy consumption.

For hydrofluorocarbon refrigerants, appropriate ILs were proposed to compose novel absorption cycle working pairs, and the cycle performance with new working pairs HFC-IL systems was assessed by means of the Aspen Plus process simulation software on the basis of the investigated thermophysical properties.

Figure 1. Solubility comparison for R32-HFCs systems

Figure 2. P-x diagram of R32-HFCs systems (298.15 K)

References [1] A.Wahlstrom and L.Vamling, International Journal of Refrigeration, (2000), 23, 597-608. [2] Z. Lei, B. Chen, C. Li and H Liu, Chemical Reviews, (2008), 108, 1419-1455. [3] L. Dong, D. Zheng, Z. Wei and X. Wu, International Journal of Thermophys, (2009), 30, 1480-1490. [4] A. Yokozeki and M. Shiflett, AIChE Journal, 2006, 52, 3952-3957 [5] J. Wang, D. Zheng, L. Fan and L. Dong, Journal of Chemical Engineerign Data 2010, 55, 2128-2132. [6] K. Kim, S. Park, S. Choi and H. J. Lee, Journal of Chemical Engineerign Data 2004, 49, 1550-1553. [7] M. Shiflett and A. Yokozeki, US20060197053A1, (2006).


PII-37. Technical Salts as Phase Change Materials

Efimova A.1, Ruck M.1, Schmidt P.2

1 - University of Technology Dresden 2 - University of Applied Sciences Lausitz

[email protected]

Many research centers all over the world are in search of new and renewable energy sources. Latent heat storage is one of the most engaging because large amounts of energy can be stored in a small volume with a small temperature change in the medium. Phase change materials (PCM) are useful for storing heat as the latent heat of fusion. Such storage has potential in heating and cooling buildings, waste heat recovery, heat pump systems, and many other applications.

Latent heat storage can be accomplished through solid-liquid and solid-solid phase transitions. The solid-liquid system is more studied and in most cases commercially available. Solid-solid systems show much promise, but are only recently being studied. For temperatures between -15 and 100 °C, storage is possible by means of using materials with a solid-liquid phase transition. It may be achieved by salts hydrate with general formula MeaXb*nH2O. These salts must be estimated along several parameters: melting and solidification temperatures, enthalpy of fusion, volume change during the melting, heat capacity of liquid and solid, thermal conductivity, corrosion, prices, etc.

The goal of the current study is to find and to develop new PCM´s, whose melting points are between 4 °C and 15 °C. The thermal characteristics of the investigated objects, such as the melting and the solidification points and the heat of fusion, were determined by differential scanning calorimetry in the temperature range from -50 °C to 50 °C. The usability of substances as storage materials is tested by measurements of the thermal hysteresis and the cycling stability.


Figure 1. DSC-measurements of thermal hysteresis and cycling stability of inorganic low-temperature PCM.


PII-38. Experimental measurements and modelling of high pressure phase equilibria of CO2+NO2 mixture

Camy S.1,2, Letourneau J.-J.3,4, Condoret J.-S.1,5

1 - CNRS ; Laboratoire de Génie Chimique ; F-31030 Toulouse, France 2 - Université de Toulouse ; INPT, UPS ; Laboratoire de Génie Chimique ; 4, Allée Emile

Monso, F-31030 Toulouse, France 3 - Université de Toulouse, Mines Albi, CNRS, F-81013 Albi, France 4 - École des Mines Albi, Centre RAPSODEE, F-81013 Albi, France

5 - Université de Toulouse ; INPT, UPS ; Laboratoire de Génie Chimique ; 4, Allée Emile Monso,F-31030 Toulouse, France

[email protected]

When partially oxidized, cellulose, a biopolymer derived from abundant renewable sources, becomes degradable in human body (a property termed “bioresorbability”) and, in addition possesses haemostatic properties (i,e., it stops the bleeding), and these properties can be advantageously used for biomedical devices, like surgical compresses for instance. The suitable oxidant for preparing such material, with both a high carboxyl content and targeted physical properties, is nitrogen dioxide (NO2). This compound ensures selective complete oxidation of the primary hydroxyl groups of cellulose, leading to partially oxidized cellulose, with the already mentioned properties. This oxidation is conventionally operated with NO2 dissolved in non-oxidable solvents, like perfluorated ones. A new process (Camy et al., 2009) using supercritical dioxide as the solvent has been recently proposed.

To develop the process, thermodynamics of the reactant-solvent system, i.e. NO2-CO2 under pressure, has to be known and modelled. This is the aim of this work, where experimental measurements of dew point pressures were done using a specific high-pressure sapphire windowed cell. A first attempt of simple modelling, using Peng-Robinson equation of state has been proposed and gave good results to predict experimental results, despite the fact that such modelling did not take into account the occurrence of the dimerization equilibrium of NO2-N2O4.

References Camy S., Montanari S., Rattaz A., Vignon M., Condoret J.-S. Oxidation of cellulose in pressurized carbon dioxide, J. Super. Fluids, 51 (2009) 188-196


PII-39. Vapour-Liquid Equilibria for Water + Ethanol and Water + Ethanol + NaCl. Experimental Measurements and

Correlations

Moreira C.M., Soares R.B., De Souza W.L.R., Mendes M.F.

Chemical Engineering Department/UFRRJ

[email protected]

The phase equilibrium knowledge is essential for the project and design of separation processes in chemical engineering. Equilibrium data at normal and high pressures are important to establish correct conditions of temperature and pressure for the separation processes and to supply the capacity of the solvent, the compositions of the phases and the selectivity of the solvent. In this work, vapor-liquid equilibrium data were measured, at normal pressure, using an ebuliometer, designed in the laboratory, based on other works and well worked for other systems studied previously. The systems investigated were ethanol-water and ethanol-water-salt because of the importance in the purity in the alcohol production nowadays. The salt chosen was the sodium chloride. The ebuliometer used, was constructed with glass and is based on the Othmer, can measure bubble and dew points. The experimental data measured in this work were compared to other data yet published in the literature and were modeled using a model that can describe the equilibrium with electrolytes. The model was proposed by Macedo et al. (1990) and based on the work of Seader et al. (1960). For the calculation adding the saline effect, the model combines the modified UNIQUAC equation with the Debye-Huckel term. Two systems were studied varying the salt composition in the mixture of 0.10 and 0.14 molar. All the experimental and calculated data, using the salt, did not have the presence of the azeotrope and the relative deviations in temperature and vapor phase did not exceed 3.5%.

Introduction The separation of mixture components is of extreme importance in the chemical industry where distillation is the mostly separation method used. Some mixtures that have near boiling points or azeotrope points, like water-ethanol, present difficulties in the components separation. The total separation of the components needs the addition of a third substance in the distillation column, capable to alter the vapor-liquid equilibrium behavior of the mixture. Normally, the added substance is a liquid solvent and this type of distillation is called extractive or azeotropic, depending on the volatility of the solvent.

Some salts can also modify the liquid-vapor equilibrium of the mixtures through the complex formation with the components to be separated. Differently from the liquid solvents, the salts are not vaporized in the distillation process and, because of that, they decrease the energy consume motivating their use substituting the liquid solvents.


The production of renewable fuels has been stimulated in Brazil due to the large area to be used for the biomass cultivation and because of the favorable weather for the sugarcane to the ethanol production. However, the distillation engineering for the ethanol production has little changed in recent decades and this situation is more pronounced using salts in a packed distillation column. As some systems like water-ethanol-salt did not have published data of vapor-liquid equilibrium, necessary for the HETP (height equivalent theoretical plate) calculation, this work had as objective the measurement of these data of water-ethanol and water-ethanol-salt systems in an ebuliometer under atmospheric pressure.

Materials and methods

Materials Distilled water and ethanol (99.9% VETEC QUIMICA, Rio de Janeiro, Brazil) were used to prepare the different solutions. The sodium chloride was also purchased from VETEC QUIMICA (Rio de Janeiro, Brazil).

Experimental procedure Figure 1 presents the ebuliometer used in the measurement of vapor-liquid equilibrium data of the systems. The analyses were done using the refractive index and a calibration curve was constructed.

Figure 1. Ebuliometer used for the measurements under atmospheric pressure


Results Figure 2 shows the two curves with the different concentrations of salt predicted by the model.

References [1] Macedo, E. A., Skovborg, P., Rasmussen, P. Calculation of phase equilibria for solutions of strong electrolytes in solvent-water mixtures, Chemical Enginnering Science, v. 45 (4), p. 875-882, 1990. [2] Seader, B., Fredenslund, A., Rasmussen, P. Calculation of vapor-liquid equilibria in mixed solvent/salt systems using an extended UNIQUAC equation, Chemical Engineering Science, v. 41 (5), p. 1171-1183, 1986.


PII-40. Thermodynamic modeling of cold properties in light crude oils

Coto B.1, Martos C.1, Espada J.J.1, Robustillo M.D.1, Peña J.L.2

1 - Department of Chemical and Energy Technology, ESCET, Universidad Rey Juan Carlos, Madrid, Spain

2 - Repsol Technology Centre, Madrid, Spain

[email protected]

Precipitation of petroleum waxes when temperature decreases is an undesirable phenomenon for petroleum industry since the presence of solid waxes increases fluid viscosity and its accumulation can block of filters, valves and pipelines. All these facts increase operational costs and are identified as “flow assurance problems”. Potential wax deposition problems can be anticipated if the main variables involved in the process, namely the wax appearance temperature (WAT) and the wax precipitation curve (WPC), are known or can be predicted. The prediction of these variables is usually carried out by using thermodynamic models that require as input experimental information on the molecular weight, the n-paraffin distribution and/or the wax content of the crude oil. Important research has been made to develop reliable thermodynamic models to describe the solid-liquid equilibrium involved in the wax precipitation process. Nevertheless, they are often in poor agreement with the few experimental data available. Some of these discrepancies are mainly due to the existing uncertainty in the determination of a reliable n-paraffin distribution to feed the model.

Usually, experimental methods based on gas chromatography (GC) have been used for that purpose. However, these methods are limited especially in the determination of heavy n-paraffins because of the low signal/noise ratio. Frequently, this determination requires including empirical extrapolation procedures. Recently, a method based on Differential Scanning Calorimetry (DSC) has been successfully applied to determine the n-paraffin distribution for crude oils [1].

In this work, the solid-liquid equilibrium of some light paraffinic gas-free crude oils has been studied in order to obtain their WAT and WPC. Experimental data [2] were used to check the predictive capabilities of a model previously reported [3]. Required n-paraffin distribution of the crude oil was obtained by high temperature gas chromatography (HTGC) and DSC and the molecular weight by gel permeation chromatography (GPC), respectively. Reasonable agreement was found between experimental and predicted results.


References [1] B. Coto, C. Martos, J.J. Espada, M.D. Robustillo, D.Merino-García, J.L. Peña. Study of New Methods To Obtain the n-Paraffin Distribution of Crude Oils and Its Application to Flow Assurance. Energy Fuels 2010. In press [2] M. D. Robustillo. Aseguramiento de Flujo en Crudos de Petróleo: Estudio de la Precipitación de Parafinas. PhD Thesis, Universidad Rey Juan Carlos, ESCET, Móstoles, Madrid, Spain, Julio 2010. [3] J. A. P. Coutinho, B. Edmonds, T. Moorwood, R. Szczepanski, X. Zhang. Reliable Wax Predictions for Flow Assurance. Energy Fuels 2006, 20, 1081–1088.


PII-41. Excess enthalpies of bio-fuel additives: binary mixtures containing dibutyl ether (DBE) or 1-butanol and 1-

hexene

Montero E.A.1, Aguilar F.1, Alaoui F.1, Segovia J.J.2, Villamañán M.A.2

1 - Universidad de Burgos (Spain) 2 - Universidad de Valladolid (Spain)

[email protected]

Alternative and renewable energy technologies are being sought throughout the world to reduce pollutant emissions and increase the efficiency of energy use. Recently n-butanol and DBE have been proposed as an alternative to conventional gasoline and diesel fuels [1-3]. Interest in butanols as a second-generation bio-fuel has increased because they have many advantages over other potential alternative fuel candidates such as ethanol. They have a higher energy content for a given volume than ethanol, and almost as much as gasoline, with a similar contribution to the antiknock effect. The DBE can be obtained as an added valued additive to second generation bio-fuels, and can be also used as cetane enhancer in bio-diesel fuel. 1-butanol is a basic component in the synthesis of the ether, and therefore is always contained as an impurity.

Ether + hydrocarbon and alcohol + hydrocarbon mixtures are of interest as model mixtures for gasoline in which the alcohol and the ether act as non-polluting, high octane number blending agents. From this point of view the study of the binary mixtures DBE + 1-hexene and 1-butanol + 1-hexene is very interesting.

Experimental excess enthalpies of the binary systems DBE + 1-hexene and 1-butanol + 1-hexene at 298.15 K and 313.15 K are reported in this work.

Excess enthalpies have been measured with a quasi-isothermal flow calorimeter. Previous measures of ether + hydrocarbon, alcohol + hydrocarbon and ether + alcohol + hydrocarbon mixtures have been reported [4-7] to study the energy effect of mixing the oxygenated additives with linear, cyclic, branched and aromatic hydrocarbons. This work studies the corresponding effect when mixing the oxygenated additives with olefins.

The experimental data have been fitted using the Redlich-Kister polynomial equation for binary and ternary systems. The values of the standard deviation indicate the agreement between the experimental results and the fitted ones. The experimental results have been fitted using the NRTL and UNIQUAC models.

We acknowledge support for this research to the Ministerio de Ciencia e Innovación, Spain, Projects ENE2009-14644-C02-01 and ENE2009-14644-C02-02.


References [1] Directive 2009/28/EC of the European Parliament ad of the Council on the promotion of the use of energy from renewable sources. [2] M. Gautam, D. Martin, Proc. Inst. Mech. Eng. A, J. Power Eng., (2000), 214, 497–511. [3] R. Kotrba, Ahead of the Curve, Ethanol Producer Magazine, 2005, November. [4] F. Aguilar, F. Alaoui, C. Alonso-Tristán, J.J. Segovia, M.A. Villamañán, E.A. Montero, J. Chem. Eng. Data, (2009), 54, 1672-1679. [5] F. Aguilar, F. E. M. Alaoui, J. J. Segovia, M. A. Villamañán, E. A. Montero, Fluid Phase Equilib., (2009), 284, 106-113. [6] F. Aguilar, F. E. M. Alaoui, J. J. Segovia, M. A. Villamañán, E. A. Montero, J. Chem. Thermodyn., (2010), 42, 28-37. [7] F. Aguilar, F. E. M. Alaoui, J. J. Segovia, M. A. Villamañán, E. A. Montero, Fluid Phase Equilib., (2010), 290, 15-20.


PII-42. Heat capacities and densities of the binary mixture 1-butanol + cyclohexane up to 50 MPa

Torine G.A., Martín M.C., Villamañán R.M., Chamorro C.R., Villamañán M.A., Segovia J.J.

University of Valladolid

[email protected]

Knowledge of the thermophysical properties of organic liquids is of great importance in various fields of science and technology. There are many interesting mixtures, from an industrial point of view, as oxygenated additives from renewable sources that may be found in next-generation biofuels. This study focuses on the thermodynamic characterization of a new blend of 1-butanol (known as a second generation biofuel) and cyclohexane using volumetric and isobaric heat capacities measurements, to continue their contribution to the international effort towards development and use of environmental sustainable fuels.

The paper presents the isobaric heat capacities of the binary mixture 1-butanol + cyclohexane at T=293.15; 313.15 K and pressures up to 20 MPa. The densities have been measured at four temperatures (273.15 K to 333.15 K) and pressures up to 50 MPa.

An automated flow calorimeter has been developed for the accurate measurement of isobaric heat capacities for pure compounds and mixtures over the range T =(250 to 400) K and p = (0 to 20) MPa. The technique has been checked for different compounds and at different conditions of temperature and pressure. The results have been compared with the literature values available. The conclusion of this comparison is that the new calorimeter can measure heat capacities with an estimated total uncertainty better than 0.5% [1].

Densities have been measured by means of an automated Anton Paar DMA HPM vibrating-tube densimeter which has been automated with an estimated uncertainty ± 7·10-4 g·cm-3 for temperatures below 373.15 K [2].

References [1] J.J. Segovia, D. Vega-Maza, C. Chamorro, M.C. Martín, J. Supercrit. Fluids, 46 (2008) 258-264. [2] J.J. Segovia, O. Fandiño, E.R. López, L. Lugo, M.C. Martín, J. Fernández, J. Chem.Thermodyn. 41 (2009) 632-638.


PII-43. Experimental (p, ρ, T) properties of binary mixtures of carbon dioxide with nitrogen

Mondéjar M.E., Chamorro C.R., Segovia J.J., Villamañán M.A., Martín M.C., Villamañán R.M.

Universidad de Valladolid

[email protected]

Thermodynamic behavior of gaseous mixtures of natural gas components can be estimated by the equation of state for natural gases. This equation of state, valid in a wide range of temperatures and pressures, is based on up to date experimental data for different pure components and mixtures. Due to the lack of accurate and reliable (p, ρ, T) data for some components, mixture parameters for some mixtures are fitted with very few data.

Accurate density measurements for three binary mixtures of carbon dioxide with nitrogen (xCO2 = 0.10, 0.20 and 0.50) were performed at temperatures between 250 K and 400 K up to pressures of 20 MPa in order to check the fitting of the mixture parameters. The measuring technique used, a single sinker densimeter with magnetic suspension coupling, is one of the state of the art methods for gas thermodynamic behavior determination.

Obtained values at low pressures for the mixtures densities fit those calculated with the equation of state within less than 0.05 percent in density. However, a big deviation is observed for 250 K and 275 K isotherms at high pressures. This deviation reaches values of 0.15 percent for xCO2=0.10, 0.25 percent for xCO2=0.20 and much higher for xCO2=0.50.

These results suggest that the mixing parameters of the equation of state at low temperatures and high pressures should be revised. Data presented here are a contribution to the mixtures properties data base for a better fitting of these parameters.


PII-44. Predictive Correlation of Phase Equilibria for CO2 + n-Alkane Binary Systems Based on Cubic Mixing Rules

Cismondi Duarte M.1,2, Rodríguez Reartes S.B.1, Milanesio J.M.1, Zabaloy M.S.1

1 - PLAPIQUI - UNS - CONICET 2 - IDTQ - UNC - CONICET

[email protected]

The qualitative and quantitative knowledge of phase equilibria and thermodynamic properties of mixtures containing CO2 and hydrocarbons are important, among other technological applications, for a better understanding of the mechanisms and consequently a better design of CO2 based enhanced oil recovery methods (CO2 -EOR).

Binary mixtures of CO2 with n-alkanes, from the lighter to the heavier ones, have been studied by an important number of authors, both experimentally and using different types of models. An important degree of inaccuracy or scatter can be realized when comparing data from different sources, especially for the more asymmetric systems (long chain alkanes). At the same time, modeling studies have generally achieved only partially accurate results in the correlation of phase equilibrium data in wide ranges of temperature and pressure.

During the last years we have dedicated some effort and a few publications to explore the possibilities that the flexible Cubic Mixing Rules (CMRs) offer for the modeling of asymmetric systems – where quadratic mixing rules fail – and to develop parameterization procedures. In this contribution, we present accurate results of predictive correlations for individual systems in wide ranges of temperature and pressure, based on a three-parameter cubic equation of state (the RK-PR EOS) coupled to CMRs.

The results achieved so far for the correlation of the complete series of CO2 + n-alkane binary systems as a whole, with carbon number-dependent parameters, are also presented, discussing strengths and limitations. Future work includes the study of prediction and correlation of ternary mixtures phase equilibria.


PII-45. Calculation Of Critical Lines Of Ternary Systems

Pisoni G.O.1,2, Rodríguez Reartes S.B.2, Cismondi Duarte M.1,2, Zabaloy M.S.2

1 - IDTQ - UNC - CONICET. Córdoba, Argentina 2 - PLAPIQUI - UNS - CONICET. Bahía Blanca, Argentina

[email protected]

The phase diagrams corresponding to the fluid phase equilibria of ternary systems may be quite complex, especially when wide ranges of conditions are considered. It is often necessary to describe such phase diagrams with the help of thermodynamic models. It is desirable to have available a calculation tool able to generate ternary phase diagrams in an automated way. Such calculation tool should be robust, it should account for all situations of practical interest and it should be applicable over wide ranges of conditions. The software to be developed should have available a number of subroutines for calculating equilibrium hyperlines which characterize the phase behavior of ternary systems, e.g., critical, three-phase and azeotropic lines at specified temperature or pressure. Similarly, once the values for the model parameters have been set, for a given ternary system, it is necessary to compute certain set of univariant lines. Such lines make possible to build a map, in the pressure/temperature plane, which characterizes the phase equilibria over a wide range of conditions. An example of a ternary univariant hyperline is a line of four-phase equilibria. Another example of a ternary univariant hyperline is the one which connects critical end points, where a ternary critical phase is at equilibrium with a ternary non-critical fluid phase. We focus in this work on the robust calculation of ternary critical hyperlines obtained after specifying a degree of freedom, such as temperature. We consider models of the equation of state (EOS) type and use them in wide ranges of conditions. We carry out the calculations using numerical continuation methods (NCMs), which make possible to minimize the user intervention during the computation of a complete hyperline. The present work builds on previous developments which were limited to binary systems. NCMs can deal with highly non-linear hyperlines. NCMs cleverly minimize the possibility of lack of convergence. However, NCMs have not been sufficiently exploited in the field of phase equilibrium thermodynamics. To the best of our knowledge, NCMs have not been previously used for computing ternary critical hyperlines. This is done in the present work. The non-linear system of equations corresponding to the critical conditions of a fluid mixture has been considered in the literature in a number of alternative ways. In this work, we discuss the relative convenience of the available approaches from the standpoint of the features of the present work, i.e., focus on ternary systems and computation through NCMs.


PII-46. Solubility prediction of 1,8-cineole in a solvent mixture at high pressure

Zacur Martínez J.L.

Facultad de Ingeniería, Universidad Nacional de Jujuy, Gorriti 237 San Salvador de Jujuy, Argentine

[email protected]

Introduction The extraction of active ingredients contained in plant matrices using high-pressure fluid is under active investigation. The solvent more used is carbon dioxide (CO2). However, solvent capacity is limited by its low polarity. The addition of co-solvents expands its potential use. Knowledge of components solubilities in high-pressure fluids is essential in the design of separation processes. The modeling of phase behavior enables the correlation and prediction of these solubilities, supplementing or replacing experimental information. The solubility of 1,8-cineole in CO2 and 1,1,1,2-tetrafluoroethane (HFC-134a) has been experimentally measured [1]. The results indicate a greater affinity relative of these terpenoid to HFC-134a respect CO2. A model is available, based on a group contribution equation of state (GCA-EoS), which includes groups that make up the molecular structure of 1,8-cineole, CO2 and HFC-134a, to estimate the behavior of the latter compound as co-solvent of 1,8-cineole in supercritical CO2. In this article, the potential use of these fluorinated hydrocarbon as co-solvent for the selective extraction of 1,8-cineole (the active ingredient of eucalyptus oil) is analyzed by the GCA-EoS. This is achieved by computing the behavior of the solubility in a solvent mixture at different pressures and temperatures, and compared with the observed behavior in pure CO2 as solvent.

Methodology The GCA-EoS model is a group contribution equation of state. A more complete description of the model can be found in [2] and [3]. A summary and review of parameter matrix have been made in [3]. The computational method is based on solving a system of non-linear equations formed by isofugacity equation and mass balance, applied to a ternary, biphasic system. Stability analysis, according to Michelsen [4], is also made. The solubility behavior of mixtures of 1,8-cineole in supercritical CO2 + 10% HFC-134a, compared with which occurs in pure supercritical CO2 are evaluated by the model. Two approaches are considered. First, the variation of the solubility with density is studied. Second, the solubilities ratio (e) with and without co-solvent is computed as a function of pressure and temperature. The temperatures and pressures are 333.2, 343.2 and 353.2 K, and 75 to 90 bar respectively.


Results and Discussion The first approach is shown in Fig. 1. There is a shift between the two lines, for a 10% molar of HFC-134a in the solvent mixture, so that the solubility of 1,8-cineole in this mixture would be higher than in pure CO2, at any mixture density.

Figure 1. Solubility behavior of 1,8-cineole vs density [Mol L-1] at 333.2 K.

Figure 2. Dependence of (e) with temperature and pressure at constant composition of the co-solvent (10% molar). Calculated with GCA-EOS

The second approach is shown in Fig. 2. It can be inferred that for this system, the solubility in the modified fluid would increase compared to pure supercritical CO2, with increasing pressure and decreasing temperature.

Conclusions The model predicts a higher solubility of 1,8-cineole in CO2 + 10%HFC-134a mixtures compared to the one presented in CO2 pure. Solubility in accordance with the model would increases with pressure and would decreases with temperature.

References [1] J. L. Zacur. PhD Dissertation. Universidad Nacional de Salta, Argentina, (2008). [2] O. Ferreira, E. Brignole, E. Macedo, J. Chem. Thermodynamics (2004), 36, 1105-1117. [3] T. Fornari. Fluid Phase Equilibria (2007), 262, 187-209. [4] M. L. Michelsen. Fluid Phase Equilibria (1982), 9, 1-19.


PII-47. Influence of the size ratio on the volumetric properties of binary mixtures

Balankina E.S.

Moscow State University for instrumental engineering and information technology

[email protected]

The approach for description of structure of liquid multi-component system has been developed by such structural characteristic as the packing coefficient, the intrinsic density, the volume of molecule. In ideal mixture two pure geometric conditions have to be fulfilled, namely, 1) the equality of molecular volumes

1 2

0 0 0w w wV V V= = and 2) the

values of packing density are the same for mixture and initial components 0

1 2per

mY y y y= = = . From these structural conditions it follows that the molar volumes of mixture and the initial components are the same:

( ) ( )0 0 0 0 01 2

per mix perm w m A w A wV V Y x N V y x N V y V= = + = ,

and the intrinsic density is 2 2 2 2

0 0 0 0

1 1 1 1i

perm i i i w i i w i i

i i i iD x M xV x M V x D

= = = =

= = =∑ ∑ ∑ ∑ .

In this case the density and the isothermal compressibility coefficient are 2 2

0 0

1 1

per per perm m m A i i A i i

i id D Y N x D y N x d

= =

= = =∑ ∑ ,

1 2

0 01 2m

perT T Tx xβ β β= + .

Therefore, the requirement of geometric identity of structures (equality of packing density, size and shape of molecules) leads to linear dependence with respect to mole fraction (xi) for these properties, rather than with respect to volume fraction, as is found in the case of thermodynamically ideal mixture.

Let us consider binary mixture in which the value of the excess enthalpy is zero but two abovementioned conditions are not fulfilled. In this case the intrinsic density is

( ) ( )2 1

2 2mod 0 0 0 0 0 0

1 2 2 11 1

im i i w w i wi i

D x D x x V V xV D D= =

= + − −

∑ ∑ .


If the size ratio (the ratio of molecular volumes 2 1

0 0w wk V V= ) lies in the range from 1 to

8, than the packing density of binary mixture is [1] 2

mod 0

1m i i

iY F y

=

=∑ ,

where 2

0 0

1i ii i w i w

iF xV xV

=

= ∑ is the volume fraction. Therefore, the molar volume of such

mixture is

( )

( ) ( ) ( )

2 0 021 2mod 0

1 2 2 21

12 1 2 0 0

1 2

ˆ 11

1 1m i i

i

y y yV xV x x

k yxk x x xk k y y

=

∆

= − − ∆ + − − − −

∑ . (1)

This expression allows to calculate the contribution of pure geometric factor (k, ∆y=y20–

y10) in the excess volume of real mixtures ( 0E

m m i ii

V V xV= −∑ ). In mutual mixtures of

nonassociated homologous such as n-alkane, n-alkene or c-alkane and aqueous mixtures of nonelectrolyte the main contribution to the E

mV values gives the geometric factor. The calculated values of molar volume of C7H16 – C6H14 and C8H18 – C6H14 according to expression (1) are in a good agreement with experimental ones.

References Balankina E.S. The structural differences of initial components and thermodynamic properties of mixtures // Materialovedenie (In Russian). – 2010. – N7. – P.14-18


PII-48. Effect of gravitational force on two-phase flow regimes during condensation inside a microfin tube

Akhavan-Behabadi M.A., Mohseni S.G.

School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran

[email protected]

One of the passive techniques to enhance heat transfer coefficient is the use of microfin tubes. Microfin tubes represent a technology that is able to beneficially enhance the heat transfer without causing a large increase in the pressure drop. It is obvious that the flow pattern in a condenser tube plays an important role on the characteristics of heat transfer. A review of the existing literature reveals that, although vast studies have been done on flow regimes in these tubes, yet the focus of almost all of the studies is on two phase refrigerant flow in horizontal tubes. However, the flow regime is influenced by interfacial shear stress, surface tension and gravitational force. Therefore, a visual study has been carried out to determine the flow patterns for condensation of R-134a inside a microfin tube with different inclinations of the tube.

Test apparatus and procedure The experimental set-up was a well instrumented vapor compression refrigeration system. It is consisted of a compressor, an evaporator, an expansion valve, a pre-condenser, a test-condenser or test-section, an after-condenser, and necessary instruments for measurements and controls. The microfin tube is a copper tube having internal microfins with triangular fin cross-section. The geometrical parameters of microfin tube are the same as that we used in our previous word [1]. A sight glass is mounted at the end of test section for flow pattern visualization. The sight glass, which is made of Pyrex glass, has a length of 100 mm and an inner diameter identical to that of the test section. A diffuse white film pigmented with evenly spaced black stripes is placed in the background (behind the glass tube) and illuminated. This method has been originally developed by Jassim et al. [2]. The microfin tube has been provided with different tube inclination angles of the direction of fluid flow from horizontal, α. The experiments were performed for seven different tube inclinations in a range of -90° to +90°.

Results

The results demonstrate that the tube inclination angle, α, affects the flow regimes in a significant manner. Annular flow was the dominant flow pattern for vertical downward flow, α = -90°. Annular flow, semi annular flow and stratified flow were observed for α = -60° and -30°. Annular flow, wavy-annular flow, and stratified-wavy flow exist in sequence for horizontal tube. Annular flow and wavy-annular flow were observed for α


= +30° and +60°. Annular flow, wavy-annular flow, churn flow and slug flow occurred for α = +90°. Fig. 1 illustrates the flow pattern maps for condensation inside the microfin tube with inclination angle of +90°. The Weber number for the liquid phase is taken along abscissa, while the Weber number for the vapor phase along the ordinate. The corresponding Weber numbers are defined respectively as:

2L L LWe = J Dρ σ; 2

V V VWe = J Dρ σ; (1)

( )L L V VWhere: J = G 1-x ρ ; J = Gx ρ

Figure 1. Flow pattern map for condensation inside the microfin tube with inclination angle of

+90˚.

References [1] M.A. Akhavan-Behabadi, Ravi Kumar, S.G. Mosheim, Condensation heat transfer of R-134a inside a microfin tube with different tube inclinations, International Journal of Heat and Mass Transfer, (2007), 50, 4864-4871. [2] E.W. Jassim, T.A. Newell, J.C. Chato, Probabilistic determination of two-phase flow regimes in horizontal tubes utilizing an automated image recognition technique, Experiments in Fluids, (2007), 42, 563-573.


PII-49. Determination of the operating parameters of an evaporator crystallizer. Liquid/solid equilibria in the NaCl-

NaOH-H2O ternary system

Dhenain A., Bougrine A.J., Frangieh M.R., Delalu H.

Université Claude Bernard Lyon 1, Laboratoire Hydrazines et Procédés, France

[email protected]

This work deals with the study of solid/liquid equilibria in the NaOH/NaCl/H2O ternary system, with the aim to optimize operating conditions of an evaporator crystallizer used at an industrial scale in the extraction process of a hydrazine prepared by the Raschig way. The Raschig process is a general method for preparing hydrazines (H), for spatial and pharmaceutical applications.

H is obtained through Raschig way in two successive stages. The first step involves the synthesis of monochloramine from sodium hypochloride and excess ammonia. The second step consists in reacting, in a basic medium, the resulting monochloramine with an excess of amine (A), to provide the corresponding hydrazine H. This process is a clean and selective method, distinguished by its non-polluting aspect (chemistry in water without use of organic solvent), its low cost (inexpensive reagents NH3 and NaOCl) and the feasibility of a continuous transposition to an industrial scale. However, this method has some disadvantages linked to the low hydrazine concentrations in the synthesis solutions (3 to 4%w, despite a 93% yield), due to the dilution of the initial reactants and the existence of a large number of secondary interactions that impose non-stoichiometric conditions at all stages of the synthesis. It is therefore necessary to multiply the preconcentration steps to isolate and purify the final product. Raschig synthesis medium generally contains hydrazine, amine in excess, ammonia, sodium chloride and sodium hydroxide.

The extraction process involves several steps. The first one is generally the evaporation of the excess of ammonia and amine by stripping. The synthesis medium is then composed of hydrazine (2.6%w), water, sodium hydroxide and sodium chloride. The use of a Kestner type elutriator is then usually required. This latter is a crystallizer evaporator, which allows, first, to isolate hydrazine (4.6%w) and water by evaporation, and second to separate the two salts: sodium hydroxide, recovered as an aqueous solution, and sodium chloride which crystallizes. The evaporated aqueous solution of water and hydrazine successively undergoes azeotropic distillation, then demixing by adding sodium hydroxide, leading to the azeotrope breaking, and finally a final rectification, to collect the hydrazine with purity higher than 99.5%.

This work deals with the optimization of the evaporation-crystallization step (Kestner). Indeed, problems of NaCl-NaOH coprecipitation may be encountered in industry,


leading to the blockage of the facilities. Now, we must ensure that we do crystallize only NaCl, while maintaining NaOH at the liquid state. The knowledge of the equilibria of the NaCl-NaOH-H2O ternary system is thus required, particularly the liquid / solid equilibria.

These equilibria were determined by ITA (Isoplethic Thermal Analysis), an original method developed in our laboratory. The operating temperature of the Kestner device being generally in the temperature range 40-80°C, the 40 ° C and 70 ° C isotherms were determined experimentally. The isotherm at 80 °C, which is difficult to implement by ITA, was determined by extrapolation. Finally, the NaCl crystallization domain was entirely determined and the operating parameters (temperature/composition) of the Kestner device were precisely defined in order to precipitate pure NaCl, while keeping NaOH as an aqueous solution.


PII-50. LLE in the Pyrrolidine/Water/NaOH Ternary System – Experimental Study and Critical Point

Determination

Frangieh M.R.1,2, Bougrine A.J.1,2, Tenu R.2,3, Dhenain A.1,2, Counioux J.J.2,3, Goutaudier C.2,3

1 - Laboratoire Hydrazines et Procédés - UMR CNRS 5179 2 - Université de Lyon

3 - Laboratoire Multimatériaux et Interfaces - UMR CNRS 5615

[email protected]

Our work focuses on the synthesis, extraction and purification of a new exocyclic hydrazine with fine chemistry applications, the N-aminopyrrolidine (NAPY). The synthesis reactions of hydrazines are carried out by the Raschig way, which rests on the reaction of a large excess of amine with monochloramine in aqueous alkaline medium and without any use of organic solvent. The definition and optimization of the extraction parameters require then the knowledge of the Water/Pyrrolidine/N-aminopyrrolidine ternary system involved in these operations, especially the liquid/liquid equilibria under atmospheric pressure.

Firstly, it is useful to add, to the reaction medium, Sodium Hydroxide that permits, by salting-out, to remove a large quantity of Water, which is known as the biggest consumer of energy during the distillation process. The demixing of the crude solutions of synthesis is controlled by the quantities of the excess reactant (Pyrrolidine), the Sodium Hydroxide and the solvent (Water). The optimization of the operating conditions of this pre-concentration step by demixing (temperature, composition, pressure and quantity of Sodium Hydroxide added) requires then the knowledge of the Pyrrolidine/Water/Sodium Hydroxide ternary system under atmospheric pressure.

With this aim, three isothermal sections were investigated at 283 K, 293 K and 323 K, by combination of ITA (Isoplethic Thermal Analysis) and chemical analysis. When a miscibility gap appears in a ternary system, one critical point at least, stable or metastable, can be observed. The experimental determination of this invariant point is difficult and we propose a computing method in order to calculate the composition of the invariant solution. The calculation is based on the barycentric properties of the bimodal points and an extension of the diameter method. The results are presented and validated by means of consistency test (Othmer-Tobbias and Hand).

The knowledge of the solid-liquid and liquid-liquid equilibria of these isotherms will thus give us the relevant quantities of Sodium Hydroxide to be added according to the demixing temperature, and the compositions of the organic and aqueous phases as function of the global composition of the crude synthesis solution.


PII-51. Distillation Path in the Liquid-Vapor Equilibria Pyrrolidine/Water/N-Aminopyrrolidine Ternary System

Goutaudier C.1,2, Frangieh M.R.2,3, Tenu R.1,2, Bougrine A.J.2,3, Dhenain A.2,3

1 - Laboratoire Multimatériaux et Interfaces - UMR CNRS 5615 2 - Université de Lyon

3 - Laboratoire Hydrazines et Procédés - UMR CNRS 5179

[email protected]

The know-how of the team focuses on the development of integrated original processes, including the synthesis, extraction, purification and stability of solid or liquid hydrazines. The methods of preparation are selective and clean and permit to produce and extract, by use of the particularisms involved in the phase diagrams, a hydrazine in conformity with the particularly restricting specifications (pharmaceutical, cosmetic or spatial applications as propellants). This work covers the experimental determination of the binary limit systems and then the prediction of the distillation path in the pyrrolidine/water/N-aminopyrrolidine ternary system, in order to extract the useful pure product.

The synthesis and extraction process of the N-aminopyrrolidine (NAPY), an exocyclic hydrazine, is presently studied, due to its fine chemical applications. The synthesis reaction of this hydrazine, by the Raschig way [1], rests on the reaction of a large excess of Pyrrolidine with Monochloramine (NH2Cl), in an aqueous alkaline medium and without any use of organic solvent. This synthesis differs by its little polluting feature, its low economic cost, the speed of the rate reactions, its selectivity and its feasibility for a continuous transposition. However, it presents some disadvantages associated with the low hydrazine content of the reaction liquors and to non-stoichiometric conditions. Nevertheless, we can overcome this by a pertinent exploitation of the phase diagrams involved in the steps of isolation, extraction and treatment of the effluents.

In most of cases, the extraction and purification steps of the useful product are often linked to successive demixing and distillation operations. In the case of NAPY, the definition and optimization of these extraction parameters requires then the knowledge of the Pyrrolidine/Water/N-aminopyrrolidine ternary system involved in these operations and in a first step, the three binary limit systems. Then, the modeling of the ternary system will be considered under two hypotheses. The first takes into account the possible existence of an azeeotrope between water and hydrazine. The second considers only three binary ideal behaviors of solutions. The figure below shows the path distillation of a ternary mixture according to the two hypotheses.

At the same time, a study of the influence of the substitute on the thermodynamic properties of amines, linear or no, having the same number of carbon atoms as the pyrrolidine, was carried out, in order to deduce a law of comportment for these amines and then for the corresponding hydrazines with application to the extraction process.


Three binary systems Water/Diethylamine, Water/Butylamine and Water/Pyrrolidine were thus studied at atmospheric pressure and compared with previous works [2-4].

References [1] F. Raschig, Chem. Ztg, 40 (1907) 926 [2] V.M. Komarov, B.K. Krichevtsov, Zhurnal Prikladnoi Khimï, 39 (1966) 2834 [3] J.L. Kopp, D.H. Everett, Disc. Faraday Soc., 15 (1953) 174 [4] H.S. Wu, L.E. William, S.I. Standler, J. Chem. Eng. Data, 35 (1990) 169


PII-52. The Influence of the Seed Preparation on Granulometric Characteristics and Polymorphism at Glycine

Crystallization

Prlić Kardum J., Hrkovac M., Duvančić M., Matijašić G.

Faculty of Chemical Engineering and Technology, University of Zagreb, Croatia

[email protected]

Influence of the seeding process on the granulometric characteristics and polymorphism of crystals during batch cooling crystallization was examined.

Crystals which were used as seed in the experiments were obtained from different crystallization methods what finally caused different characteristics of obtained crystals.

The analyzed material was glycine, which is the simplest amino acid and is found in many proteins and enzymes. It is used in food, pharmaceutical and cosmetic industries. There are three known polymorphic structures of glycine: α, β and γ - glycine.

Different additives (1.8 g C2H2O4/100ml, 4.8 g C2H5OH/100ml and 7 g NaCl/100 ml of water) were used in the batch cooling crystallization.

Additives present in a growth medium lead almost always to a change in the solubility of the solute. A natural consequence of the change in the solubility of the compounds is that the concentration of ions/molecules of the solute present in the medium and the solute–fluid interfacial energy are altered. All these lead to changes in the metastable zone width and influence the nucleation process and the crystal growth. Therefore, the crystals obtained by adding different additives had different polymorphic forms. XRD analysis confirmed occurrences of γ glycine obtained by adding sodium chloride or oxalic acid, while α polymorphs were achieved by adding ethanol.

10 15 20 25 30 35 40 45 502Theta / °

I/I m

ax

4.8 g EtOH

8 g NaCl

1.8 g C2H2O4

Figure 1. Standard XRD pattern (γ glycine-black dotted line and α glycine-gray dotted line) and XRD pattern of glycine obtained by adding different additives.


Obtained crystals were grinded 8 minutes in the planetary ball mill. The seed in one experiment was original salt of glycine (α structure). Distribution of the seed size was 180 – 355 µm.

Although all experiments were carried out at the same process condition, the obtained kinetic curves and granulometric characteristics of crystals depended on the seed quality. Higher level of supersaturation and wider multimodal crystal size distribution were obtained by using seed from crystallizations with additions of oxalic acid and sodium - chlorides. The original glycine seed yields a regular and narrow crystal size distribution.

0

0.01

0.02

0.03

0.04

0.05

0.06

0 50 100 150 200 250

t ( min)

∆X

(kg g

/ kg w

)

PG

1,8g C2H2O4*2H2O

7g NaCl

4,8g EtOH

0.00

0.05

0.10

0.15

0.20

0.25

0 500 1000 1500 2000 2500

x av (mm)

q3(

xav

) (m

m-1

)PG

1,8g C2H2O4*2H2O

7g NaCl

4,8g EtOH

Figure 2. Supersaturation profile and crystal size distribution for all experiments. Crystal habit did not change much after grinding in planetary ball mill. But after seeded crystallization, the change was significant.

1.8g C2H2O4/100ml

4.8 g C2H5OH/100ml

7 g NaCl/100 ml

a) b) c) Figure 3. Comparison of crystal habit obtained after: a) crystalization with additive, b)grinding in planetari ball mill and c) seeded crystalization. DSC analysis confirmed that addition of seeds prepared in a different ways did not affect the formation of different polymorphs.


PII-53. Choline Based Ionic Liquid Properties

Makowska A., Szydłowski J.

University of Warsaw, Faculty of Chemistry, Żwirki I Wigury 101, 02-089 Warsaw, Poland

[email protected]

Knowledge of ionic liquid properties will provide a fundamental insight into the particular behavior of these solvents what can play an important role in process design.

Quaternary ammonium ionic liquid (2-hydroxyethyl)trimethylammonium bis(trifluoromethylsulfonyl)imide (short name -choline bistriflimide) is the subject of our presentation.

A variety of physicochemical properties of this compound; density, viscosity, specific conductivity, compressibility, refractive index and the liquid-liquid miscibility with water, heavy water and alcohols will be presented. All these mentioned properties were investigated in a wide temperature range.

Choline bistriflimide is an ionic liquid with quite high density 1.518 g/cm3, conductivity of 2.25 mS/cm, and moderate viscosity - 67 cP (all properties at 308.15 K). It is not miscible with water at room temperature (the UCST for that system is 346.3 K). We have also found the limited miscibility with aliphatic alcohols. The miscibility curves represent phase diagrams with the upper critical solution temperatures with marked asymmetry. The solubility of choline bistriflimide in investigated alcohols decreases with an increase of the alkyl chain length of an alcohol.

As a continuation of our previous work on isotope effects in mutual solubility of ionic liquids with organic solvents, we determined the miscibility curve of [(CH3)3-N+-CH2-CH2-OH][NTf2

-] with heavy water.


334

336

338

340

342

344

346

348

350

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

mole fraction of IL

T /K

Figure 1. Phase diagram for choline bistriflimide with H2O ( ) and D2O ( )

The positive isotope effect in CST [∆Tc=Tc(D)-Tc(H)=2.3 K] (Fig.1) was found. Worsening of miscibility due to deuteration of water was described in literature for [BMIM][BF4] /water system. In the case of this system deuterium substitution provokes the upward shift of UCST as well. It is mainly due to the fact that deuteration of water makes deuterium bonding stronger so the worsening of miscibility is expected.


PII-54. Isotope effects on miscibility of [C8MIM][NTf2], [C8MIM][BF4] and [C8MIM][PF6] with hexanol and heptanol

Siporska A., Szydłowski J.

Faculty of Chemistry, University of Warsaw

[email protected]

Miscibility data of room-temperature ionic liquids (RTIL) with regular alcohols and appropriate deuterated alcohols, accessible in the literature, are really scarce [1]. So that, twelve phase diagrams of [C8MIM][NTf2], [C8MIM][BF4] and [C8MIM][PF6] with regular alcohols (hexanol – HexOH, heptanol - HepOH) and with deuterated in hydroxyl group (HexOD, HepOD) have been constructed. The miscibility of ionic liquids containing BF4

-, PF6- and NTf2

- ions with regular alcohols is in the accordance with the literature data [2,3], i.e. the smallest two-phase region is observed for NTf2

- ion

and the largest one for PF6-, and shorter alkyl chain of alcohol makes miscibility better

(Figure 1).

Figure 1. Miscibility of [C8MIM][NTf2]/HexOH(◊),[C8MIM][NTf2]/HepOH(♦), [C8MIM][BF4]/HexOH (), [C8MIM][BF4]/HepOH (),[C8MIM][PF6]/HexOH() and [C8MIM][PF6]/HepOH () systems.

270

290

310

330

350

370

0 0,1 0,2 0,3

mole fraction of ionic liquid

tem

pera

ture

/ K


The statistical analysis employing nonlinear least-squares fits based on the scaling equation leads to the critical parameters, especially the upper critical temperatures (Tc) and critical mole fractions (xc) of investigated systems. The differences in critical temperatures between systems with regular and deuterated alcohols, called miscibility isotope effects (∆Tc), are listed in Table 1. Table 1. Critical parameters (temperatures - Tc, mole fractions - xc) and isotope effects (∆Tc) of measured systems. IL system xc Tc/K ∆Tc =Tc(D)-Tc(H)/K [C8MIM][NTf2]/HexOH 0.136±0.003 279.8±0.1 [C8MIM][NTf2]/HexOD 0.134±0.003 280.4±0.1

0.6

[C8MIM][BF4]/HexOH 0.126±0.002 301.76±0.02 [C8MIM][BF4]/HexOD 0.122±0.002 300.08±0.01 −1.68

[C8MIM][PF6]/HexOH 0.123±0.002 355.63±0.01 [C8MIM][PF6]/HexOD 0.121±0.002 355.24±0.01 −0.39

[C8MIM][NTf2]/HepOH 0.105±0.003 293.41±0.07 [C8MIM][NTf2]/HepOD 0.105±0.002 293.25±0.06 −0.16

[C8MIM][BF4]/HepOH 0.144±0.003 309.45±0.02 [C8MIM][BF4]/HepOD 0.132±0.002 308.01±0.01 −1.44

[C8MIM][PF6]/HepOH 0.131±0.002 369.30±0.02 [C8MIM][PF6]/HepOD 0.131±0.002 368.41±0.02 −0.89

The analysis of presented above values leads to the very interesting observations: (i) critical mole fractions are almost independent of isotope substitution, (ii) deuterium isotope substitution generates remarkable isotope shift of the UCST and its direction and the magnitude strongly depends on the system, (iii) the highest values of isotope effects are observed for ionic liquid with BF4

- anion (−1.44K and −1.68K for heptanol and hexanol, respectively), (iv) isotope effects become more positive in the range: BF4

-

<PF6-<NTf2

-, (v) the differences in values of isotope effects between [C8MIM][NTf2] and [C8MIM][BF4] mixed with investigated alcohols is significant and equal to approx. 2.3K and 1.3K for hexanol and heptanol, respectively.

[C8MIM][NTf2]/hexanol is the first ionic liquid/alcohol system in which positive value of miscibility isotope effect has been observed.

References [1] A. Makowska, A.Siporska and J.Szydlowski, J.Phys.Chem.B, (2006), 110, 17195-17199. [2] M.Wagner, O.Stanga and W.Schröer, Phys.Chem.Chem.Phys., (2003), 5, 3943-3950. [3] J.M.Crosthwaite, N.V.K.Aki, E.J.Maginn and J.F.Brennecke, Fluid Phase Equilib., (2005), 228-229, 303-309.


PII-55. Relationship between refractive index and density of mixtures containing imidazolium ionic liquids with water and

ethanol

Rilo E.1, Domínguez-Pérez M.1, Segade L.1, Vila J.1, Varela L.M.2, Cabeza O.1

1 - Faculty of Sciences, Univ. of A Coruña. Campus A Zapateira s/n. E-15008. A Coruña, SPAIN 2 - Nanomaterials and Soft Matter Group.Departament of Condensed Matter Physics, University

of Santiago de Compostela, E-15782. Santiago de Compostela, SPAIN

[email protected]

We present experimental measurements of the refractive index of Na D-line (nD) for binary mixtures of four ionic liquids (IL) of the family 1-alkyl-3-methyl imidazolium tetrafluoroborate, CnMIM-BF4, with water and ethanol. The alkyl chains studied are ethyl (EMIM), butyl (BMIM), hexyl (HMIM) and octyl (OMIM). As published earlier, only BMIM-BF4 is completely miscible with water and ethanol, EMIM-BF4 is only partially miscible with ethanol but miscible with water for all range of concentrations. In contrast, HMIM-BF4 is only partially miscible with water and OMIM-BF4 is not miscible with water at all, but both are miscible with ethanol in all range of compositions [1].The refractive index data will be analyzed using Newton’s phenomenological model, which relates the refractive index of the mixture with the corresponding density data without any fitting parameters [2]. This same model has been used previously by some of us to relate both sets of data for non electrolytic mixtures [3]. The density data used are taken from those published in Reference [1], where it was demonstrated the ideality of all mixtures from the molar volume point of view. Then we will only need refractive index and density of both pure mixture compounds (IL and water or ethanol) to predict nD of each mixture.

The refractive index was measured using an Atago refractometer, with a sensibility of 1·10-4. The ionic liquids used are from Solvent Innovation (recently absorbed by Merck) and have purities better than 99%, except EMIM-BF4, whose purity is better than 98%. The water used is Milli Q grade, and the ethanol is from Panreac with purity better than 99.5%. The original IL tins were opened into an inert atmosphere cabin with a relative humidity grade lower than 10%, and the different mixtures were prepared and sealed into that cabin, so we avoided water adsorption by the ILs. In Figure 1(a) we plot data for the different aqueous mixtures measured, while in Figure 1(b) the same for the mixtures with ethanol, both at 298 K and vs. the IL molar fraction, xIL. As observed, the curves for the different solvents present different shape, being more progressive the increase of the nD value for the ethanol mixtures than that for aqueous mixtures. Thus, for aqueous mixtures the 80% of the nD value increase from its value for pure solvent to that of pure IL happens for only xIL = 0.2, while for ethanol systems the equivalent value is reached around xIL = 0.4. The nD data for all systems measured where related with the corresponding density, ρ, using the equation known as Newton’s model. This model had been tested by some of


us to relate nD and ρ for binary systems of non-electrolyte liquids, with very good results [3]. Data for density will be obtained taking into account that all the analyzed systems are ideal from the molar volume point of view, as demonstrated in Ref. [1]. This fact allows us to obtain density for all range of concentrations from only the value of pure components

, (1)

where S means solvent, and M is the molar mass. Newton’s model allows obtain refractive index of the system at any concentration from the value of nD of the pure components and their respective volume fractions, φi, defined as

, (2) where, obviously, suffix i means IL or S. Finally, Newton’s equation reads [2],

. (3) In Figure 1 we plot the obtained curves, and the corresponding standard deviation, s, are also included for each system. As one can observe, Newton’s equation fit very accurately to the experimental data for all the analyzed IL-mixtures.

1.33

1.35

1.37

1.39

1.41

1.43

0.0 0.2 0.4 0.6 0.8 1.0

n

xLI

1.33

1.35

1.37

1.39

1.41

1.43

0.0 0.2 0.4 0.6 0.8 1.0

n D

xLI

EMIM:s= 0.0024BMIM: s= 0.0022HMIM: s= 0.0020

1.33

1.35

1.37

1.39

1.41

1.43

0.0 0.2 0.4 0.6 0.8 1.0

n D

xLI

EMIM:s= 0.0028BMIM: s= 0.0022HMIM: s= 0.0023OMIM: s= 0.0011

Figure 1. Refractive index vs. IL molar fraction at T = 298 K for (left) the aqueous systems and (right) systems with ethanol for: (solid rhombus) EMIM-BF4, (open triangle) BMIM-BF4, (solid square) HMIM-BF4 and (open circle) OMIM-BF4. The solid line corresponds to the best fit of Newton’s equation (3) to the measured data. This work was supported by the Spanish Ministry of Science and Innovation in conjunction with the European Regional Development Fund (Grants Nº FIS2007-66823-C02-01 and Nº FIS2007-66823-C02-02), and by the Directorate General for R+D+i of the Xunta de Galicia (Grants Nº 10-PXI-103-294 PR and Nº 10-PXIB-206-294 PR). References [1] E. Rilo et al., Fluid Phase Equilibria (2009), 285, 83-89. [2] S.S. Kurtz, A.L. Ward, J. Franklin Inst. (1936), 222, 563–592. [3] E. Rilo et al., J. Chem. Thermodyn. (2003), 35, 839-850.


PII-56. Volumetric Behaviour of Binary and Ternary Liquid Systems Composed of Ethanol, Isooctane, and Toluene at

Temperatures from 298.15 K to 328.15 K

Linek J., Morávková L., Wagner Z., Sedláková Z.

Institute of Chemical Process Fundamentals of the ASCR, v.v.i., Prague, Czech Republic

[email protected]

The densities and speeds of sound of (ethanol + isooctane), (ethanol + toluene), and (ethanol + isooctane + toluene) were measured at four temperatures over the range 298.15 K to 328.15 K, and the respective values of excess volumes E

mV and adiabatic compressibility κS were calculated. The E

mV and κS values for the binary systems were fitted to the Redlich-Kister equation. The respective ternary data together with corresponding binary data were then fitted to the modified Redlich–Kister equation considering various numbers of ternary constants. It was found that even for the systems containing self-associating alcohol, only one ternary parameter is sufficient to describe well the ternary system.

The authors acknowledge the partial support from the Grant Agency of the Czech Republic; the work has been carried out under grant No. 104/09/0666.

Figure 1. Excess molar volumes EmV /(cm3 mol-1) plotted against mole fraction of components

for (x1 ethanol + x2 isooctane + x3 toluene) at T = 298.15 K and atmospheric pressure.


PII-57. Measurement of Solid–Liquid and Liquid–Liquid Equilibria in Organic System Containing Ionic Liquid

[emim][NTf2]

Sedláková Z.1, Rotrekl J.2, Bendová M.1, Vrbka P.2, Aim K.1

1 - Institute of Chemical Process Fundamentals of the ASCR, v. v. i.., Rozvojová 135, 165 02 Prague 6, Czech Republic

2 - Department of Physical Chemistry, Institute of Chemical Technology, Technická 5, 166 28 Prague 6, Czech Republic

[email protected]

Introduction The knowledge of solid–liquid(-liquid) equilibria (SLLE) is important in many fields of industrial chemistry (e.g. design of crystallization processes, safe operation of pipelines etc.). Acquisition of experimental SLLE data is prerequisite for the improvement of pertinent predictive models. SLLE data can directly be used for the design of crystallization processes and, in particular, for selecting the suitable solvents for extractive crystallization processes [1].

Experimental Liquidus temperatures were obtained by evaluation of warming curves [2]. Liquid–liquid equilibria were determined by volumetric [3] and cloud-point [4] methods.

Generally, the determination of temperature was reproducible within 0.15 K in consecutive experiments. Composition could be calculated with the accuracy of ± 0.0001 in mole fraction.

Results Experimental data for solid–liquid and liquid–liquid equilibria are displayed in Figure 1. From the experimental data obtained, activity coefficients of ionic liquid [emim][NTf2] were calculated and modeled by the Redlich-Kister equation. The experimental data were compared to calculated data assuming ideal behavior in the liquid phase.


x1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

T / K

220

240

260

280

300

320

Figure 1. Experimental data for solid–liquid and liquid–liquid equilibria in the binary system diethylamine (1) + ionic liquid [emim][Tf2N] (2), solid–liquid equilibrium, liquid–liquid equilibrium (volumetric method), solubility curve (cloud-point method)

Acknowledgements This work is supported by the Czech Science Foundation under Grant No. 203/09/P141, by the Ministry of Education, Youth and Sports of the Czech Republic under Grants MSM 604 613 7307 and MEB 021009, and by the Grant No. IAA400720710 awarded by the Grant Agency of the Academy of Sciences of the Czech Republic.

References [1] L. Negadi, M. Wilken, J. Gmehling: J. Chem. Eng. Data (2006) 51,1873-1876. [2] I. Malijevská, Z. Sedláková: J. Molec. Liquids (2006) 125(1), 72-75. [3] M. Bendová, Z. Wagner: J. Chem. Eng. Data (2006) 51(6), 2126-2131. [4] I. Malijevská, Z. Sedláková, K. Řehák, P. Vrbka: Collect. Czech. Chem. Commun. (2006) 71(9), 1350-1358.


PII-58. Comparison of Excess Volumes for Two Ternary Systems containing (Toluene + Isooctane) with Ethanol or 1-

Butanol

Morávková L., Wagner Z., Sedláková Z., Aim K.

Institute of Chemical Process Fundamentals of the ASCR, v. v. i.., Rozvojová 135, 165 02 Prague 6, Czech Republic

[email protected]

The subject of the study is detailed experimental investigation of densities and excess volumes in two ternary systems containing toluene + isooctane + alkanol (ethanol or 1-butanol) and their comparison.

Experimental Liquid densities were measured by Anton Paar Density & Sound Analyzer DSA 5000 for ternary systems (toluene + isooctane + ethanol) and (toluene + isooctane + 1-butanol) as well as for all the 5 constituent binary subsystems (toluene + isooctane), (toluene + ethanol), (isooctane + ethanol), (toluene + 1-butanol), (isooctane + 1-butanol) at four temperatures covering the range from 298.15 K to 328.15 K.

In case of the ternary systems (toluene + isooctane + ethanol) and (toluene + isooctane + 1-butanol), the measurements were conducted along four cuts of pseudo-binaries (toluene + isooctane) + ethanol and (toluene + isooctane) + 1-butanol, respectively. The mole fractions of isooctane in the (toluene + isooctane) mixture were approximately 0.2, 0.4, 0.6 and 0.8; ethanol or 1-butanol was then added to cover its whole molar range.

Results From the primary density data the corresponding values of excess volumes were calculated and fitted to a modified Redlich-Kister equation. Comparison of excess volumes for the two investigated ternary systems at temperature 298.15 K is depicted in Figure 1. It is clearly observed that binary systems (ethanol + isooctane) and (toluene + isooctane) show positive deviations from ideality, whereas binary systems (toluene + 1-butanol), (isooctane + 1-butanol) and (ethanol + toluene) possess S-shaped character. There is a pronounced temperature dependence of excess volumes in the studied systems, which will be discussed in detail.

Acknowledgements Financial support of the Grant Agency of the Czech Republic (Grant No. 203/09/P141), Programme Nanotechnology for Society of the Academy of Sciences (Project No.


KAN400720701), and the Grant Agency of the Academy of Sciences of the Czech Republic (Grant No. IAA400720710) is gratefully acknowledged. Vm

E (cm3 · mol-1) Figure 1. Excess volumes for ternary systems (toluene + isooctane + ethanol) and (toluene + isooctane + 1-butanol) at temperature 298.15 K:

– in color (toluene + isooctane + ethanol); – gray (toluene + isooctane + 1-butanol).


PII-59. Application of Thermodynamic Consistency Lines to the VLE and LLE Data

Kato S., Tachibana H.

Department of Applied Chemistry, Tokyo Metropolitan University, Japan

[email protected]

It has been a long-standing problem to establish a reliable thermodynamic consistency test for the consistency evaluation of the phase equilibrium data. Kato [1] recently proposed thermodynamic consistency (TC) lines that can evaluate the data consistency. The present investigation summarizes the TC lines applied to not only binary VLE data, but also binary and ternary LLE data and high-pressure VLE data. The TC lines are also used for predicting phase equilibria.

Fig. 1 demonstrates the TC line of the methanol(1)–water(2) binary, which was determined using the VLE data. It has been shown [1] that i) each binary has its own TC straight line, and ii) constant-temperature and constant-pressure data converge to the same TC line. Fig. 2 demonstrates the TC lines determined from mutual solubility data [2, 3]. Fig. 2 shows that the data fluctuations involved in the TC lines determined using binary LLE data are less than those from the VLE data [3].

1

10

1 10 100 1000 104

Methanol(1)-water(2)

Constant temperature dataConstant pressure data

P, ps,ave

[kPa]

TC line

Fig. 1. The TC line of the methanol(1)-water(2) binary.

2

4

6

8

10

0.1 1 10 100 1000

(p1s+p

2s)/2 [kPa]

20

Phenol(1)-water(2)

2-Butanone(1)-water(2)

Fig. 2. The TC lines of the 2-butanone(1)- water(2) and phenol(1)-water(2) binaries.

Fig. 3 demonstrates the TC lines determined using the VLE data including alkanes above critical points. Figs. 1 and 3 show that the high-pressure data converge to the same TC line determined using the low-pressure data. In Fig. 4, the system pressure is plotted versus the mole fraction of methanol for the methanol(1)–water(2) binary, in


which solid lines were predicted using the TC line of the methanol–water binary and the infinite dilution activity coefficients [4]. Fig. 4 shows that the prediction using the TC line is excellent. The TC lines determined using the binary VLE and LLE data were used for evaluating the thermodynamic consistency of the ternary LLE data [1].

0.0001

0.001

0.01

0.1

1

10

0.1 1 10 100

(p1s+p

2s)/2 [MPa]

Ethane(1)-decane(2)

Propane(1)-decane(2)

Ethane(1)-butane(2)

Propane(1)-pentane(2)

Fig. 3. The TC lines of alkane(1)-alkane(2) binaries

0.01

0.1

1

10

0 0.2 0.4 0.6 0.8 1

Methanol(1)-water(2)

Mole fraction of methanol [-]

373.15 K

333.15 K

298.15 K

Fig. 4. P-x relationships for the methanol(1)-water(2) binary, (－) predicted using the TC line, (, , , ×, ＋) data.

In summary, the TC lines are useful for evaluating the thermodynamic consistency of the phase equilibrium data and the prediction of VLE and LLE. Readers can use the TC lines at http://www.sskato.jp.

References [1] S. Kato, Fluid Phase Equilibria, in print, http://dx.doi.org/10.1016/j.fluid.2010.10.027. [2] J. M. Sorensen, W. Arlt: Liquid-Liquid Equilibrium Data Collection, Binary Systems, Chemistry Data Series, Vol. V, Part 1, DECHEMA, (1979). [3] S. Kato, H. Tachibana, Solv. Ext. Res. Dev., Japan, in print, http://www.solventextraction.gr.jp/serdj/index.html [4] P. Vrbka, D. Fenclova, V. Lastovka, V. Dohnal, Fluid Phase Equilib. 237 (2005) 123-129.


PII-60. High-Pressure Phase Equilibria of CO2 + Styrene and CO2 + Vinyl acetate. Use of different experimental methods

Dohrn R.1, Haverkampf V.1, Peper S.2

1 - Bayer Technology Services GmbH 2 - Helmut-Schmidt University, Hamburg

[email protected]

The experimental determination of high-pressure phase equilibria is often the only suitable method to obtain reliable data because high-pressure phase behavior is complex and difficult to predict. This contribution gives a brief classification of applied experimental methods [1, 2]. A new high-pressure apparatus is described, which can be used for phase-equilibrium measurements with different experimental methods, namely the analytical-isothermal method, the synthetic-isothermal method as well as the non-visual- and the visual-synthetic method. The different techniques have been tested for the measurement of the phase behavior of systems containing CO2 + styrene and CO2 + vinyl acetate [3]. The measured data were compared with data from literature and discussed in terms of accuracy, advantages and drawbacks of the applied methods. The comparison of the results measured with different methods shows good agreement. Furthermore, all determined data sets agree well with good literature data.

vent

thermostat

VCR

transducer

vacuum

elec.

12

bellows oil

3

5

4

7

8

9

gas

1012

12

12

6

11

sampling valve

sampling valve

TIR

PI

PIPIR

Figure 1. Experimental Set-up The comparison of different data sets from the literature of the systems investigated shows that applying the same experimental method not necessarily results in the same


phase equilibrium data. Deviations between data sets are in some cases significantly higher than the accuracy of the experimental data given by the authors. Often this can be explained by the fact that sources of error of the experimental procedure and deficiencies of the apparatus were overlooked. This emphasizes the importance of the knowledge and understanding of the different experimental methods, their advantages and disadvantages as well as their specific error sources. The quality of the experimenter usually has a higher influence on the quality of the results than the applied experimental method. Furthermore it can be concluded that for a reliable evaluation of experimental results the data of different experimental methods and/or from different experimenters should be compared.

Figure 2. CO2 + styrene system: Pressure-composition diagram. Data evaluation.

References [1] R. Dohrn, S. Peper, J.M.S. Fonseca, High-pressure fluid-phase equilibria: experimental methods and systems investigated (2000-2004), Fluid Phase Equilib. 288 (2010) 1-54. doi: 10.1016/j.fluid.2009.08.008 [2] J.M.S. Fonseca, R. Dohrn, S. Peper, High-pressure fluid-phase equilibria: experimental methods and systems investigated (2005-2008), Fluid Phase Equilib. 300 (2010) 1-69. doi: 10.1016/j.fluid.2010.09.017 [3] S. Peper, V. Haverkamp, R. Dohrn, Measurement of phase equilibria of the systems CO2 + styrene and CO2 + vinyl acetate using different experimental methods, J. Supercrit. Fluids 55 (2010) 537-544. doi:10.1016/j.supflu.2010.09.014

0

2

4

6

8

10

12

14

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

328 K, AnT, Tan et al. 328 K, SynVis, Suppes and McHugh328 K, SynVis, Zhang et al.328 K, SynVis, Wang et al.333 K, AnT, Akgün et al.333 K, SynVis, Zhang et al.333 K, SynVis, Wang et al.343 K, AnT, Akgün et al.348 K, AnT, Akgün et al.353 K, SynVis, this work353 K, AnPT, Bamberger et al.353 K, SynVis, Suppes and McHugh

P (M

Pa)

0.97 0.98 0.99 1xCO2, yCO2 (mol/mol)


PII-61. Phase Equlibria of Carbon Dioxide + 1-Pentanol System at High Pressures

Secuianu C., Feroiu V., Geană D.

Department of Applied Physical Chemistry and Electrochemistry, Faculty of Applied Chemistry and Materials Science, “Politehnica” University of Bucharest, 1-7 Gh. Polizu Street, 011061

Bucharest, Romania

[email protected]

In the last years, the rapid advance of the technology into new fields demands reliable and accurate experimental measurements. Phase equilibria experiments are always required for process engineering design and supercritical fluid extractions.

The supercritical fluid extractions often use a polar co-solvent, also called a modifier or entrainer, to enhance the solvation power or selectivity of the solvent. The carbon dioxide mixtures with alcohols, up to 1-hexanol, acetone and acetonitrile are the typical choices. There has been considerable recent interest in measuring phase equilibria of carbon dioxide with these co-solvents in the region supercritical to carbon dioxide [1].

0

2

4

6

8

10

12

14

16

18

20

0 0.2 0.4 0.6 0.8 1Mole fractions of CO2

P/M

Pa

T = 293.15 KT = 303.15 KT = 313.15 KT = 316.65 KT = 333.15 KT = 353.15 K

Figure 1. Comparison of experimental phase equilibrium data and predictions by SRK/MHV2.


In continuation of our previous studies [2–16] on the carbon dioxide + alcohols systems at high pressures, this work presents the results for the carbon dioxide + 1-pentanol binary mixture.

The carbon dioxide + 1-pentanol system shows type-IV fluid phase behaviour [17], according to the classification of van Konynenburg and Scott [18].

Our literature search has identified few papers on the carbon dioxide + 1-pentanol binary system presenting vapour-liquid equilibrium data. Jennings et al. [19] reported results at 314.6, 325.9, and 337.4 K, Staby and Mollerup [20] at 283.2, 313.2, 343.2, and 373.2 K, Silva-Oliver et al. [21] at 333.08, 343.69, 374.93, 414.23, and 426.86 K, Secuianu et al. [7] at 313.15 and 353.15 K, and Gutiérrez et al. [21] at 313.15,323.15, and 333.15 K. There are also papers presenting only solubility data [22-24].

In this work we present new phase equilibrium data obtained using a static-analytical method, in a high-pressure visual cell.

The experimental and literature data were modelled with several cubic equations of state coupled with different mixing rules.

An example is shown in Figure 1. The figure presents the comparison of our experimental phase equilibrium data and predictions by SRK/MHV2.

Acknowledgments The authors are grateful to the National Council for Scientific Research of Romania for financial support (grants AT 3, ID 1088, A 83).

References [1] R. Dohrn, S. Peper, J.M.S. Fonseca, Fluid Phase Equilib., (2010), 288, 1–54. [2] C. Secuianu, Ph.D. Thesis, Politehnica University of Bucharest, Bucharest, Romania. [3] C. Secuianu, V. Feroiu, D. Geană, J. Chem. Eng. Data, (2003), 48, 1384–1386. [4] C. Secuianu, V. Feroiu, D. Geană, Rev. Chim. (Bucharest), (2003), 54, 874–879. [5] C. Secuianu, V. Feroiu, D. Geană, J. Chem. Eng. Data, (2004), 49, 1635–1638. [6] C. Secuianu, V. Feroiu, D. Geană, Fluid Phase Equilib., (2007), 261, 337–342. [7] C. Secuianu, V. Feroiu, D. Geană, Rev. Chim. (Bucharest), (2007), 58, 1176–1181. [8] C. Secuianu, V. Feroiu, D. Geană, Fluid Phase Equilib., (2008), 270, 109–115. [9] C. Secuianu, V. Feroiu, D. Geană, J. Chem. Eng. Data, (2008), 53, 2444–2448. [10] C. Secuianu, V. Feroiu, D. Geană, J. Supercrit. Fluids, (2008), 47, 109–116. [11] C. Secuianu, V. Feroiu, D.Geană, Cent. Eur. J. Chem., (2009), 7, 1–7. [12] C. Secuianu, V. Feroiu, D. Geană, J. Chem. Eng. Data, (2009), 54, 1493–1499. [13] C. Secuianu, V. Feroiu, D. Geană, Rev. Chim. (Bucharest), (2009), 60, 472–475. [14] C. Secuianu, V. Feroiu, D. Geană, J. Chem. Thermodynamics, (2010), 42(10), 1286-1291. [15] C. Secuianu, V. Feroiu, D. Geană, J. Chem. Eng. Data, (2010), 55(10), 4255-4259.


[16] C. Secuianu, V. Feroiu, D. Geană, J. Supercritical Fluids, (2010), 55(2), 653-661. [17] S. Raeissi, K. Gauter, C.J. Peters, Fluid Phase Equilib., (1998), 147, 239–249. [18] P.H. van Konynenburg, R.L. Scott, Philos. Trans. R. Soc. Lond., Ser. A ,(1980), 298, 495–540. [19] D.W. Jennings, F. Chang, V. Bazaan, A.S. Teja, J. Chem. Eng. Data, (1992), 37, 337-338. [20] A. Staby, J. Mollerup, J. Supercritical Fluids, (1993), 6, 15-19. [21] G. Silva-Oliver, L.A. Galicia-Luna, S.I. Sandler, Fluid Phase Equilib., (2002), 200, 161–172. [22] J.E. Gutiérrez, A. Bejarano, J.C. de la Fuente, J. Chem. Thermodynamics, (2010), 42 591–596. [23] T. Laursen, S.I. Andersen, S. Dahl, O. Henriksen, J. Supercritical Fluids, (2001), 19, 239–250. [24] H.S. Ghaziaskar, A. Daneshfar, M. Rezayat, Fluid Phase Equilib., (2005), 238, 106–111. [25] M. Hou, S. Liang, Z. Zhang, J. Song, T. Jiang, B. Han, Fluid Phase Equilib., (2007), 258, 108–114.


PII-62. Thermochemistry of Biofuels: Reference Materials for Combustion Calorimetry of Liquids

Zaitsau Dz.H.1, Emel’yanenko V.N.1, Verevkin S.P.1, Pagel R.2, Sarge S.M.2, Wolf H.2, Morice R.3

1 - Chemical Department, University of Rostock, Dr-Lorenz-Weg 1, 18059 Rostock, Germany 2 - Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany 3 - Laboratoire national de métrologie et d'essais 29, avenue Roger Hennequin, 78197 Trappes

cedex, France

[email protected]

Precise knowledge of the thermochemical properties of biodiesel and its precursors is not only desirable for the modeling of the synthesis process but also for getting better insight into the combustion process within combustion engines. Such knowledge is based on high precision measurements of the calorific value of biofuels and of its constituents. For establishing a high precision metrology infrastructure for biofuels it is essential to calibrate the calorimeter using reference samples with carefully measured calorific values. Calibration is a fundamental requirement for every thermochemical study. It requires the establishment of a quantitatively defined relationship between the value indicated by the measuring instrument and the correct value. In the combustion calorimetry this means the determination of the energy equivalent of the calorimeter. The reproducibility of the energy equivalent of the calorimeter for the scientific measurements should be achieved on the level of 0.01%. As a rule, such repeatability is possible to be obtained using home made combustion calorimeters, but it is also possible to be reached using commercially available calorimeters (e.g. Parr 6200) after an appropriate adjustment of the periphery facilities. For combustion calorimetry benzoic acid has been usually used as a primary standard for calibration. In order to avoid systematic errors and to verify the data treatment procedure of the combustion process, the energy of combustion of secondary standards (nicotinic acid, urea, thianthrene, etc.) should be measured. However, all these reference materials are crystalline. For the verification of the combustion experiments with biofuels liquid secondary standard materials are required. Up to date, no such liquid reference materials have been suggested for combustion calorimetry. A reference material should satisfy the following requirements: it must be easily obtainable in a pure state, quite stable, non-hygroscopic, non-volatile, and physiologically harmless. In addition, reference materials must not react with the instrument material, the surrounding atmosphere and photoreactions must not occur. In the current work we have tested several representatives of the homologues series of alkanes, long chained aliphatic esters, and aliphatic alcohols as candidates for the reference materials. The selected materials were systematically studied in three thermochemical laboratories – University of Rostock (Germany), PTB (Germany), and LNE (France). Metrological recommendations for the secondary liquid materials will be discussed.


PII-63. About the capability of the PPR78 model to predict excess-enthalpy and excess-heat capacity data

Privat R., Qian J., Jaubert J.-N.


[email protected]

Today, the synthesis design and optimization steps of chemical processes require more and more to access quasi immediately to PVT properties of a nearly infinite set of molecules in order to select the most efficient ones without having to perform costly and fastidious experiments. In that purpose, group-contribution methods can be of great interest since they allow to guesstimate thermodynamic properties of a given mixture from the mere knowledge of chemical structures of molecules constituting it.

Starting from these observations, Jaubert, Privat et al. are developing since soon one decade, the so-called PPR78 model (for Predictive Peng-Robinson 1978). This predictive equation of state relies on the combination of the Peng-Robinson equation in its 1978 version with classical Van der Waals mixing rules (linear on b and quadratic on a). In addition a group contribution method is used to accurately quantify the interactions between each pair of molecules. Nowadays, the PPR78 model can manage complex mixtures containing alkanes, cycloalkanes, aromatic compounds, alkenes, carbon dioxide, nitrogen, hydrogen sulfide, mercaptans and water. Successes and failures of PPR78 in the representation of phase equilibrium properties (bubble and dew points, critical points, azeotropes, liquid-liquid phase equilibria and so on) were largely studied, published and discussed by all PPR78 contributors.

The present communication is devoted to inform about the capacity of the PPR78 model to predict excess enthalpy and excess heat capacity data since none results about such data were published in the past years. Note that excess enthalpy and excess heat capacity are very important quantities for chemical engineers because they are used to calculate the energy and exergy balances of any process. Here again, failures and successes of PPR78 will be analyzed and discussed in details. Numerical results will be provided after compilation of more than 5000 experimental data.


PII-64. Phase equilibria in alkenes-containing binary systems from the Peng Robinson EoS using temperature-dependent

BIPs (kij(T)) calculated through a group-contribution method

Qian J., Privat R., Jaubert J.-N.


[email protected]

The study of phase equilibria for mixtures containing alkenes is fundamental in petroleum and chemical industries. Therefore, the development of a predictive model for such systems is an indispensable and challenging task. In this work, four groups are added to the group-contribution (GC) model PPR78 (predictive 1978, Peng-Robinson EoS) in order to predict mutual solubility and critical loci of systems containing alkenes. Such a model combines the widely used Peng-Robinson equation of state (EoS) with a predictive method based on the GC concept, aimed at estimating the temperature-dependent binary interaction parameters BIPs (kij(T)). In our previous papers, sixteen groups were defined: CH3, CH2, CH, C, CH4 (methane), C2H6 (ethane), CHaro, Caro, Cfused aromatic rings, CH2,cyclic, CHcyclic Ccyclic, CO2, N2, H2S, -SH and H2O. It was thus possible to estimate the kij for any mixture containing alkanes, aromatics, naphthenes, CO2, N2, H2S, mercaptans and water in a large domain of temperatures. In this study, accurate results have been obtained and the addition of the four groups makes it possible to extend the PPR78 model to systems containing alkenes.


PII-65. Improvement of TG Resolution by Heating Rate Conversion Simulation Method

Okubo N.1, Rumyantsev A.2

1 - Analytical Application Engineering Department, SII NanoTechnology Inc., Shintomi 2-15-5, Chuo-ku, Tokyo 104-0041, JAPAN

2 - LABTEST

[email protected]

Thermogravimetry (TG) is widely used for the quantitative analysis of polymer materials thermal resistance test and of the polymer blend components. However, each mass change may not be measured accurately due to the reactions occur at similar temperatures while separated determination is performed for blended materials by TG. In this case, TG resolution improvement method using low heating rate measurement or CRTA (Controlled-Rate Thermal Analysis) is applied; however, there is an issue of decreased measurement efficiency due to the longer measurement time.

As a solution of this problem, Heating Rate Conversion Simulation Method is proposed [1]. This method calculates the activation energy ∆E of each reaction with regard to the decomposition reactions from TG measurement results, performs time-temperature conversion using calculated ∆E, and converts to low heating rate measurement data. TG resolution can be improved by this method.

In this study, the analysis result of the cotton-polyester blended yarn blending ratio is reported as an analytical example using the Heating Rate Conversion Simulation Method. Evaluation of the ratio of cotton and polyester components was not possible from TG raw data. However after the conversion this TG raw data to the slower heating rate measurement data by the Heating Rate Conversion Simulation Method, accurate blending ratio for cotton and polyester is obtained.

Reference [1] R. Kinoshita, R. Nakatani, Y. Ichimura and N. Nakamura, The 34th Japanese Conference on Calorimetry and Thermal Analysis, 1B1020 (1998).


PII-66. Characterization of UV Curing Polymers by Photochemical Reaction DSC System

Okubo N.1, Rumyantsev A.2

1 - Analytical Application Engineering Department, SII NanoTechnology Inc. Shintomi 2-15-5, Chuo-ku, Tokyo 104-0041, JAPAN

2 - LABTEST

[email protected]

Ultraviolet curing polymers are used in wide number of fields such as general electronics, optical electronics, medical fields, glass arts, and architecture. Curing reaction heat when the UV is irradiated can be measured real-time by using Photochemical Reaction DSC System.

Photochemical Reaction DSC System enables the real-time measurement of chemical reaction (curing reaction) behavior during UV irradiation process of UV curing resin etc by connecting the unit for the irradiation of ultraviolet light directly to sensor (sample and reference) inside DSC furnace. By this system, it enables the analysis of the relationship between UV irradiation conditions such as wavelength, irradiation intensity or temperature and the curing reaction behavior during UV irradiation with regard to the UV curing polymers.

In this study, the analysis result of Photoresist and UV curing adhesive is reported as an analytical example using Photochemical Reaction DSC System. The UV irradiation condition dependence of wavelength, irradiation intensity, or temperature against exothermic reaction heat, rate of reaction, or reaction time during UV irradiation is observed.


PII-67. Effect of the alkyl chain positions on the desulfurization ability of [HMMPy][NTf2] ionic liquids

Rodríguez-Cabo B., Francisco M., Soto A., Arce A.

Chemical Engineering Department. University of Santiago de Compostela

[email protected]

Since fuels sulfur content must be reduced due to the actual environmental legislations, many techniques are being studied to replace the hidrodesulfurization method that nowadays takes place in refineries. Extractive and/or oxidative desulfurization are emerging as novel routes to achieve a deep reduction of sulphur in fuels [1, 2].

Ionic liquids are non-volatile, usually non flammable and thermally stable, what confers them a great potential as a “green” recyclable alternative to the traditional organic solvents. Many combinations of cations and anions exist and they have, depending on the ion-combination, adjustable solvent properties. These reasons make ionic liquids perfect candidates for the extractive desulfurization [3, 4].

In this work, the influence of the alkyl chains position of the ionic liquid on the desulfurization ability was studied. For that purpose 1-hexyl-3,5-dimethylpyridinium bis(trifluoromethylsulphonyl)imide, [H-2,4-MMPy][NTf2], and 1-hexyl-2,4-dimethylpyridinium bis(trifluoromethylsulphonyl)imide, [H-3,5-MMPy][NTf2]ionic liquids were used. LLE data were obtained from the systems IL + tiophene + toluene, IL + tiophene + hexane and IL + pyridine + hexane at 298.15 K and atmospheric pressure. These data were correlated using the UNIQUAC and NRTL models and the suitability of each ionic liquid as solvent was evaluated in terms of solute distribution ratio and selectivity.

References [1] Babich, I. V.; Moulijn, J. A.; Fuel, 52, 2003, 607 [2] Otsuki, S.; Nonaka, T.; Takashima, N.; Qian, W.; Ishihara, A.; Imai, T.; Kabe, T.; Energy Fuels, 14, 2000, 1232 [3] Huddleston, J. G.; Willaurer, H. D.; Swatlosi, R. P.; Visser, A. E.; Rogers, R. D.; Chem. Com., 1998, 1765 [4] Zhao, H.; Xia, S.; Ma,P.; J. Chem. Technol. Biotechnol., 80, 2005, 1089


PII-68. Formation and characterization of oxide nanoparticles in ionic liquids

Rodríguez-Cabo B., Palmeiro I., Rodil E., Soto A., Arce A.


[email protected]

Methods for synthesizing nanoparticles arouse great interest due to their thermal, magnetic, structural and/or physicochemical enhanced properties in comparison with their bulk counterparts, since these properties depend on the size of the particles [1]. In recent years, different techniques based on the formation of microemulsions, reactions, electrodeposition, etc. have been studied for the synthesis of particles in the nanometric scale [2, 3].

Ionic liquids are salts composed of ions, whose anion-cation attractive forces make them liquid below 100 °C. These solvents have a large number of applications due to their characteristic properties, such as non-flammability, high solvency power, thermal stability and, above all, no vapor pressure, making them environmentally friendly solvents. Moreover, by suitably combining anions and cations, an ionic liquid for a specific task can be synthesized. Previously, the effectiveness of ionic liquids as synthesis media for nanomateriales has been shown [4, 5].

The formation of metal oxide nanoparticles (CdO, TiO2 and Fe2O3) using an ionic liquid as a medium, trihexyltetradecylphosphonium chloride ([P6,6,6,14] Cl) with a technique of fragmentation/dispersion is studied in the present work. These nanomaterials are perfect candidates for optoelectronic applications and for the manufacture of solar cells, phototransistors, catalytic supports, energy storage or materials industry [6-8]. The synthesized nanoparticles were characterized to confirm their composition and structure (XRPD and Raman) and their morphological characteristics and size (TEM and DLS).

References [1] Lauritsen, J. V.; Kibsgaard, J.; Helveg, S.; Topsøe,H.; Clausen, B. S.; Lægsgaard, E.; Besenbacher, F. Nature Nanotechnology 2, 2007, 53-58 [2] Rodil, E.; Aldous, L.; Hardacre, C.; Lagunas, M. C. Nanotechnology, 19, 2008, 105603 [3] Gorelikov, I.; Kumacheva, E. Chem. Mater. 16, 2004, 4122-4127 [4] Xu, Z. Y.; Zhang, Y. C. Materials Chemistry and Physics, 112, 2008, 333-336 [5] Ma, Z.; Yu, J.; Dai, S. Advanced Materials, 22, 2, 2010, 261-285 [6] Chauvin, Y.; Olivier-Bourbigou, H. Chemtech, 26, 2005 [7] Arlt, W.; Seiler, M.; Jork, C.; Schneider, T. Worl Pat., WO 074718, 2002 [8] Francisco, M.; Arce, A.; Soto, A. Fluid Phase Equilibria, 294, 1-2, 2010, 39-48


PII-69. Citrus essential oil deterpenation by liquid-liquid extraction using 1-ethylpyridinium ethylsulfate ionic liquid as

solvent

Lago S., Rodríguez H., Soto A., Arce A.


[email protected]

Nowadays, separation and commercial use of essential oils constitute an arousing interest field for both researchers and industry. The extracted essential oil purification can be carried out by different industrial processes and it is usually done to concentrate certain components to highlight some of the oil’s properties. Citrus essential oils are basically a mixture of terpenic hydrocarbons (90-95 %), oxygenated derivatives (2-5 %) and a small quantity of non volatile compounds as waxes and pigments [1]. Terpenes have a little contribution to the flavor of the essential oil [2], they are easily hydrolysable and oxidized by air or oxygen, they are not stable under heat and sun-light conditions and for all these reasons they must be eliminated to stabilize the final product [3]. It is the oxygenated compounds which give most of the organoleptic properties to the oil [2]. Selective elimination of terpenes is called deterpenation. The most used industrial techniques to carry out this process are vacuum distillation [4] and extraction with alcohols [5] or other solvents [6]. New techniques as separation with membranes [7] or supercritical fluid extraction [8] are being developed for the deterpenation of essential oils. Ionic liquids are salts with a boiling point under 100 ºC [9-11]. These low values of the boiling point are due to a week anion-cation attraction forces. Most of these salts show good properties to be considered alternative solvents in industrial applications substituting the common organic solvents [12]. Their application in liquid-liquid extraction is especially interesting. One of the most attractive characteristic of ionic liquids to be used as solvents is their negligible vapor pressure [13]. Due to this fact, the solvent’s recuperation stage can be easily done, for example, by flash distillation [14]. Another advantages of most of these salts are their thermal and chemical stability, capability to dissolve a big range of different nature compounds, they are liquid in a big range of temperatures, etc. All these properties of ionic liquids for the liquid-liquid extraction have driven to their use as solvents in the deterpenation of essential oils. Specifically, research has been centered in the use of these salts as solvents for the extraction of citrus essential oils [15-18]. In this work, the suitability of the 1-ethylpyridinium ethylsulfate ionic liquid to be used as a solvent in the liquid extraction of linalool from citrus essential oil was studied and compared with previous works [15-18]. The liquid-liquid equilibrium data of the ternary system limonene + linalool + 1-ethylpyridinium ethylsulfate was studied at 298.15 K and atmospheric pressure. Liquid-liquid equilibrium data have been reported and


correlated using the NRTL and UNIQUAC models and suitability of this solvent has been evaluated in terms of solute distribution ratio and selectivity. References [1] A. Verzera, A. Trozzi, G. Dugo, G. Di Bella and A. Cotroneo, Biological lemon and sweet orange essential oil composition, Flavour Fragr. J. , 2004, 19, 544-548. [2] A. Arce and A. Soto, en Tree and Forestry Science and Biotechnology (editores N. Benkeblia y P. Tennant), Special Issue 1, vol. 2, Global Sciences Books, London, 2009, pp. 1-9. [3] J. Owusu-Yaw, R. F. Matthews and P. F. West, Alcohol Deterpenation of Orange Oil, J. Food Sci., 1986, 51, 1180-1182. [4] G. R. Stuart, D. Lopes and J. V. Oliveira, Deterpenation of Brazilian Orange Peel Oil by Vacuum Distillation, J. Am. Oil Chem. Soc., 2001, 78, 1041-1044. [5] A. Arce, A. Marchiaro, O. Rodríguez y A. Soto, Liquid-liquid Equilibria of Limonene + Linalool + Diethylene glycol System at Different Temperatures, Chem. Eng. J., 2002, 89, 223-227. [6] M. B. Gramajo de Oz, A. M. Cases and H. N. Sólimo, (Liquid+liquid) equilibria of (water + linalool + limonene) ternary system at T = (298.15, 308.15 and 318.15) K, J. Chem. Thermodyn., 2008, 40, 1575-1579. [7] D. J. Brose, M. B. Chidlaw, D. T. Friesen, E. D. LaChapelle and P. van Eikeren, Fractionation of Citrus Oils Using a Membrane-Based Extraction Process, Biotechnol. Prog., 1995, 11, 214–220. [8] S. Diaz, S. Espinosa and E. A. Brignole, Citrus peel oil deterpenation with supercritical fluids: Optimal process and solvent cycle design, J. Supercrit. Fluids, 2005, 35, 49-61. [9] J. F. Brennecke and E. J. Maginn, Ionic Liquids: Innovative Fluids for Chemical Processing, AIChE J., 2001, 47, 2384-2389. [10] J. S. Wilkes, A short history of ionic liquids – from molten salts to neoteric solvents, Green Chem., 2002, 4, 73-80. [11] R. D. Rogers and K. R. Seddon (editors), in the preamble of Ionic Liquids as Green Solvents – Progress and Prospects, ACS Symposium Series, vol. 856, American Chemical Society, Washington DC, 2003. [12] R. M. Pagni, en Green Industrial Applications of Ionic Liquids (editors R. D. Rogers, K. R. Seddon y S. Volkov), Kluwer, Dordrecht, 2002, pp. 105-128. [13] M. J. Earle, J. M. S. S. Esperança, M. A. Gilea, J. N. Canongia Lopes, L. P. N. Rebelo, J. W. Magee, K. R. Seddon and J. A. Widegren, The distillation and volatility of ionic liquids, Nature, 2006, 439, 831-834. [14] R. E. Treybal, Liquid Extraction, 2nd ed., McGraw-Hill, New York, 1963. [15] A. Arce, A. Marchiaro, O. Rodríguez and A. Soto, Essential Oil Terpenless by Extraction Using Organic Solvents or Ionic Liquids, AIChE J., 2006, 52, 2089-2097. [16] A. Arce, A. Pobudkowska, O. Rodríguez and A. Soto, Citrus essential oil terpenless by extraction using 1-ethyl-3-methylimidazolium ethylsulfate ionic liquid: Effect of the temperature, Chem. Eng. J., 2007, 133, 213-218. [17] A. Arce, M. Francisco, S. Lago and A. Soto, Essential oil deterpenation by solvent extraction using 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate ionic liquid, Fluid Phase Equilibr., 2010, 25, 149-153. [18] J. Chem. Eng. Data, accepted to be published.


PII-70. Extraction of Sulfur or Nitrogen containing organic compounds from aliphatic hydrocarbons using ionic liquids

Kędra-Królik K., Mutelet F., Jaubert J.-N.


[email protected]

In recent years considerable attention has been given to deep desulfurization of gasoline and diesel due to the higher restrictions concerning sulfur-compounds content level in fuels. Sulfur oxides that form in gasoil combustion process contribute to acid rains, global warming effect and air pollution. Those affect urban as well as industrial areas and are harmful for human health due to secondary inorganic aerosol gases formation. The European Union gradually reduced the maximum sulfur concentration in fuels to avoid high emission of gases resulting from combustion of heavy fuels. Since 2010 the total sulfur content cannot be higher than 10 ppm. Deep desulfurization of gasoline and diesel is a very complex problem for petroleum industry and has to be solved to minimize the pollutions from fuel oils exhaust gas.

The aim of this study is to investigate the possible use of ILs as solvents for two separation problems frequently encountered in petroleum industry: aromatic sulfur compound + aliphatic hydrocarbon or nitrogen compound + aliphatic hydrocarbon. This work is focused on three ILs: 1-ethyl-3-methylimidazolium thiocyanate, 1,3-dimethylimidazolium methylphosphonate and tris-(2hydroxyethyl)-methylammonium-methylsulfate.

The new three ternary systems are studied in view of defining the capacity of proposed ILs as solvents for extraction of sulfur and nitrogen containing organic compounds from aliphatic hydrocarbons. Therefore, LLE measurements of ternary mixtures for five systems were measured at 298.15 K and at atmospheric pressure: thiophene + n-heptane + 1-ethyl-3-methylimidazolium thiocyanate, thiophene + n-heptane + 1,3-dimethylimidazolium methylphosphonate, thiophene + n-heptane + tris-(2-hydroxyethyl)-methylammonium-methylsulfate, pyridine + n-heptane + 1-ethyl-3-methylimidazolium thiocyanate, pyridine + n-heptane + 1,3-dimethylimidazolium methylphosphonate. The second section of this work presents results of extraction of synthetic fuels – model gasoline and model diesel by the use of selected ILs. The influence of extraction time or temperature as well as three stepped procedure using each time a fresh portion of ILs on the final fuel contamination was investigated.


PII-71. Thermodynamic Characterization of Trigeminal Tricationic Ionic Liquids

Mutelet F.1, Moise J.-C.1, Skrzypczak A.2, Jaubert J.-N.1

1 - Nancy-Université, Ecole Nationale Supérieure des Industries Chimiques, Laboratoire Réactions et Génie des Procédés, 1 rue Grandville, B.P. 20451, F-54001 Nancy Cedex

2 - Poznań University of Technology, Department of Chemical Technology, pl. M. Sklodowskiej-Curie 2, 60-965 Poznań, Poland

[email protected]

Much of the interest in ionic liquids is based on their promise as green substitutes for traditional industrial solvents such as volatile organic compounds. Development of safer and environmentally friendly processes and products is needed to achieve sustainable production and consumption patterns. New chemical products, such as ionic liquids, which are of great interest to the chemical and related industries because of their attractive properties as solvents, should be considered. Ionic liquids are comprised of an asymmetric, bulky organic cation and a weakly coordinating organic or inorganic anion. A large number of possible combinations allows for the ability to ‘fine tune’ the solvent properties for a specific purpose. Physical and chemical properties of ILs are not only influenced by the nature of the cation and the nature of cation substituents but also by the polarity and the size of the anion. These features infer to ILs numerous applications, in organic synthesis, separation processes and electrochemistry.

This study presents thermodynamic properties of six trigeminal tricationic ionic liquids with polar chain grafted on cation. Information on interactions of this class of ionic liquids with solutes containing polar functional groups can be obtained with infinite dilution activity coefficients. In the present work we report infinite dilution activity coefficients data obtained with several families of ionic liquids. Then, we discuss interactions between ionic liquids and organic molecules in terms of thermodynamic solvation theories. This approach makes it possible to assess characteristic features of the ionic liquids used as stationary phases in gas phase chromatography.


PII-72. Thermodynamic study of azeotropic mixtures of interest in the chemical and pharmaceutical industry

Luis P., Parvez A., Van Der Bruggen B.

Katholieke Universiteit Leuven, Department of Chemical Engineering, W. de Croylaan 46, 3001, Leuven, Belgium

[email protected]

Recycling of solvent batches from the chemical and pharmaceutical industry is a challenge due to their complex composition and difficulties in the purification step since azeotropic mixtures are observed [1]. Nowadays, incineration is the most common approach but it is a costly operation with evident environmental impact that does not allow the recycling and reuse of solvents. New strategies have to be developed in order to find technological alternatives for incineration but the first step is to understand the liquid phase behavior and thermodynamics of the mixtures.

Four mixtures that form azeotropes at specific temperature and concentration are evaluated in this work: ethylacetate/water, ethylacetate/iso-octane, acetonitrile/toluene and acetonitrile/toluene/tetrahydrofurane. An experimental study is performed to obtain the vapor-liquid equilibrium data for all the mixtures by means of headspace-gas chromatography [2]. In addition, since an important part in the design of the industrial process to perform the separation is the choice of the thermodynamic model, a comparative analysis was performed by application of different models to predict the thermodynamics of these mixtures [3]. Thus, the effect of choosing different thermodynamic models for the system description will be evaluated. The software used to perform this analysis is Aspen Engineering Suite V7.2. The selected models will be used to design and simulate the separation process based on azeotropic distillation, pervaporation and the hybrid process constituted by distillation and pervaporation.

References [1] Touriño A., Casas L.M., Marino G., Iglesias M., Orge B., Tojo J., 2003. Liquid phase behaviour and thermodynamics of acetone + metanol + n-alkane (C9-C12) mixtures, Fluid Phase Equilibria, 206, 61-85. [2] Kolb B., Ettre L.S., 1997. Static Headspace-Gas Chromatography: Theory and Practice, Wiley VCH, USA. [3] Gutierrez-Antonio C., Iglesias-Silva G.A., Jimenez-Gutierrez A., 2008. Effect of different thermodynamic models on the design of homogeneous azeotropic distillation columns, Chemical Engineering Communications, 195, 1059-1075.


PII-73. Electrostatic charging and charge transport by hydrated amorphous silica under high voltage electric field

Volpe P.L.O., Perles C.E.

Unicamp, Institute of Chemistry, Department of Physical Chemistry

[email protected]

This work was developed based on a casual observation of an electrostatic phenomenon, in which particles of amorphous silica were dragged by a DC electric field in which this material was submitted. It is a study without absolutely any report in the literature and, thus, the instrumental was projected and assembled in the laboratory to make possible to study this phenomenon.

The obtained data allowed to conclude that only hydrated silica particles are dragged by the electric field and that electric charges were stored on those particles until a value in which the electric force overcame the opposite forces acting on the particles (gravitational and capillary). The flow of particles between the two metallic electrodes generates, in the system, an electric current. Data confirmed that the superficial water layer was essential for the occurrence of this phenomenon. The transport of charges increased with the decrease of the hydration layer. It was also possible to conclude that there is no evidence of redox reactions happening, indicating that the phenomenon occurs due the injection of electrons in the conduction band of the structured water film on the silica surface, by forming hydrated electrons (H2O)n

-.

Electric current vs. time curves, obtained during gradual dehydration of the silica particles (flow of dry air 1 L min-1) allowed to establish quantitative relationships between the parameters obtained from these curves and the silica surface properties.


PII-74. Interaction of excess enthalpies and phase equilibria during supercritical antisolvent (SAS) precipitation

Pando C., Renuncio J.A.R., Cabañas A., Zahran F., Morère J.

Universidad Complutense de Madrid

[email protected]

The supercritical antisolvent (SAS) precipitation is based on the relatively low solvent power of supercritical CO2 (scCO2) for solutes such as pharmaceutical products and its good miscibility with polar organic solvents [1,2]. When the scCO2 dissolves in the solid organic solution, the liquid experiences a volumetric expansion and becomes a bad solvent for the solute that precipitates in micro and nanoparticles. These are solvent-free particles exhibiting a narrow size distribution and a morphology dependent on the CO2 + organic solvent phase equilibria [3,4]. In general, nanoparticles are obtained when the precipitation is carried out in the supercritical region. The uniformity of the resulting products becomes worse when the precipitation conditions approach the critical locus. Irregular micro-scale aggregated particles are formed in the vapor region and both dense cake and spherical clusters are produced in the vapor-liquid region.

In this study, the interactions of thermal effects and phase equilibria in SAS are analyzed. The heat evolved when scCO2 dissolves in the organic solvent (excess molar enthalpy, HE) is measured at the T and P conditions of SAS processes. Due to the low solute concentrations and the low ratio of the solution and CO2 flow rates used in SAS, the solute contribution to HE may be neglected. HE measurements for mixtures involving the solvents dimethylsulfoxide, acetone, N-methyl-2-pyrrolidone and N,N-dimethylformamide were carried out at 313.15, 323.15 and 333.15 K in the 9.00-18.00 MPa pressure range using an isothermal high-pressure flow calorimeter [5]. Results for the solvent ethyl acetate are presented here.

The CO2 + organic solvent systems exhibit exothermic or very exothermic mixing reaching HE values of −4500 J mol−1. Consequently, a local temperature increase may be expected in the SAS precipitation chamber. The T and P conditions and the mixture mole fraction have a great effect on the magnitude of HE. The relationship between the thermal effects and phase equilibria for SAS micronizations described in the literature [3] is discussed. HE values are correlated using cubic EOS and the local T increases are calculated. The CO2 + organic solvent mixtures initially miscible in the whole mole fraction range are shown to exhibit phase splitting for the CO2-rich mixtures usually formed in SAS. This may explain the agglomerated or irregular particles observed at average T and P conditions where uniform particles could have been expected. In order to confirm the interaction between excess enthalpies and phase equilibria, a SAS apparatus is currently being tested at our laboratory.


References [1] A. Shariati, C. J. Peters, Recent developments in particle design using supercritical fluids, Current Opinion in Solid State and Materials Science 7 (2003) 371–383. [2] A. Martín, M. J. Cocero, Micronization processes with supercritical fluids: fundamentals and mechanisms. Advanced Drug Delivery Reviews 60 (2008) 339−350. [3] E. Reverchon, G. Caputo, I. De Marco, Role of Phase Behavior and Atomization in the Supercritical Antisolvent Precipitation, Industrial and Engineering Chemistry Research 42 (2003) 6406–6414. [4] E. Reverchon, E. Torino, S. Dowy, A. Brauer, A. Leipertz, Interactions of phase equilibria, jet fluid dynamics and mass transfer during supercritical antisolvent micronization, Chemical Engineering J. 156 (2010) 446–458. [5] F. Zahran, C. Pando, A. Cabañas and J.A.R. Renuncio, Measurements and modeling of high-pressure excess molar enthalpies and isothermal vapor-liquid equilibria of the carbon dioxide + N,N-dimethylformamide system J. Supercritical Fluids, 55 (2010) 566-572.


PII-75. Ultrasonic speeds and isentropic functions of aqueous mixtures of 1-propoxypropan-2-ol from 283.15 to 303.15 K

Lampreia I.M.S.1, Santos A.F.S.1, Reis J.C.R.1, Figueiras A.O.1, Moita M.L.C.J.2, Pinheiro L.M.V.3

1 - Chemistry and Biochemistry Department, Center of Molecular Sciences and Materials, Faculty of Sciences, Lisbon, Portugal

2 - Chemistry and Biochemistry Department, Center of Chemistry and Biochemistry, Faculty of Sciences, Lisbon, Portugal

3 - Research Institute for Medicines and Pharmaceutical Sciences, Faculty of Pharmacy, University of Lisbon, Portugal

[email protected]

Due to environmental impact of chemical processes, the replacement of organic solvents with water + amphiphilic compounds that can form micelles or micelle-like aggregates is very important. The thermodynamic characterization of these mixtures is then interesting either from practical or theoretical points of view.

In this work, accurate sound speed values are reported for aqueous binary mixtures of 1-propoxypropan-2-ol (1-PP-2-ol) over the whole composition range and temperatures between (283.15 and 303.15) K at intervals of 5 K. Their values have been combined with those of the molar volumes to obtain isentropic compressibility, using the Newton-Laplace equation. Apparent molar isentropic compressions of 1-PP-2-ol as well as excess molar isentropic compressions were derived.

An analytical method based on Redlich-Kister fitting equations for excess molar isentropic compressions, as a function of the mole fraction, has been used to obtain excess partial molar isentropic compressions, for both components. Limiting values of this last property were then obtained and compared with those for isomeric compounds.

Results were analyzed in terms of branching, structural and conformational effects on the self association of both compounds and on the cross interaction between 1-PP-2-ol and water molecules through H-bonding.

Auxiliary solvatochromic probes were also used to give further insight on the influence of medium polarity on aggregation pattern changes, along the whole compositon range. These last studies were conducted at 298.15 °C, using UV–Vis spectrometry.

References [1] G. Douhéret, M. I. Davis, J. C. R. Reis, I. J. Fjellanger, M. B. Vaage and H. Høiland, Phys. Chem. Chem. Phys., 2002, 4, 6034-6042. [2] I. M. S. Lampreia, F. A. Dias, M. J. A. Barbas and A. F. S. S. Mendonça, J. Phys. Chem. Chem. Phys., 2003, 5 (7), 1419-1425. [3] M. L Moita, R. A. Teodoro, L. M. Pinheiro, J. of Mol. Liq., 2007, 136, 15-21.


PII-76. Chemical activities in aqueous mixtures of 1-propoxypropan-2-ol at 283.15 K

Santos A.F.S.1, Silva J.F.C.C.1, Moita M.L.C.J.2, Lampreia I.M.S.1

1 - Chemistry and Biochemistry Department, Center of Molecular Sciences and Materials, Faculty of Sciences, University of Lisbon, Lisbon, Portugal

2 - Chemistry and Biochemistry Department, Center of Chemistry and Biochemistry, Faculty of Sciences, University of Lisbon, Lisbon, Portugal

[email protected]

Water activity in aqueous binary mixtures of 1-propoxypropan-2-ol (1-PP-2-ol) was measured in the whole composition range, at 283.15 K. Experimental data were obtained using the humidity indicator HygroLab 3 (Rotronic), connected to a thin film capacity sensor, the AW-DIO water activity probe. Samples were kept at constant temperature in the WP-40TH sample container. The apparatus was regularly calibrated with certified humidity standards. To improve accuracy, a supplementary calibration was implemented, using standard aqueous KCl solutions freshly prepared, with water activities similar to those expected for the aqueous solutions containing 1-PP-2-ol.

Using the Gibbs-Duhem equation, water activity data were used to calculate the activity coefficients of 1-PP-2-ol. Least-squares fitting representations of the water activity coefficients data by n-suffix Margules equations were done. Statistical F-test was used in order to choose the adequate number of coefficients. Infinite dilution activity coefficients of 1-PP-2-ol and water were then obtained and compared with those found in literature for aqueous systems of 1-PP-2-ol isomeric compounds.

Excess molar Gibbs energy was also derived and positive values were found, pointing out to a non favourable stability probably due to the proximity of a miscibility gap, already reported in the literature. Comparison of the present results with those for the aqueous system containing 2-butoxyethanol was made.

References 1. S. P. Pinho, J. Chem. Eng. Data, 2008, 53, 180-184. 2. K. Kojima, S. Zhang and T. Hiaki, Fluid Phase Equilibria, 1997, 131, 145-179. 3. H. L. Cox, W. L. Nelson and L. H. Cretcher, J. Am. Chem. Soc., 1927, 49, 1080-1083.


PII-77. Receptor properties of nanoporous material based on oligopeptides toward vapor of organic compounds

Efimova I.G.1, Ziganshin M.A.1, Gorbatchuk V.V.1, Ziganshina S.A.2, Chuklanov A.P.2, Bukharaev A.A.2

1 - A.M. Butlerov Institute of Chemistry. KFU 2 - Zavoisky Physical–Technical Institute

[email protected]

The research on, and development of, oligopeptides based microporous materials have become one of major areas in material science, supramolecular chemistry, and crystal engineering.

In present work, sorption capacity of the oligopeptides L-alanyl–L-valine, L-valyl–L-alanine and L-leucyl-L-leucyl-L-leucine towards organic guest was determined using quartz crystal microbalance (QCM) technique. A specific change of surface morphology of oligoipeptides treated with vapors of various organic guests was observed by atomic force microscopy (AFM). The thermal stability of the inclusion compounds was studied by simultaneous thermogravimetry and differential scanning calorimetry combined with mass-spectrometry of evolved vapors (TG/DSC/MS).

The “structure-properties” relationships for the molecular recognition of organic compounds by oligopeptide layers were determined.

Figure 1. (a) Response of QCM sensor coated with dipeptide L-valyl–L-alanine to some organic vapors; (b) AFM image of the L-valyl–L-alanine film after the binding of pyridine vapor and further dried with hot air. It was found that sorption of a relatively large and/or hydrophobic molecules is caused by an irreversible change in surface morphology of the film oligopeptides, with the formation of nanoislands with varying topology (Fig.1b).


The geometry of the nanosized islands on the oligopeptides surface was quantitatively characterized. The average size and height of nanoislands, size distribution, and roughness of the surface were determined.

It was shown that micro- and nanocrystals formed on the surface of the thin film tripeptide L-leucyl-L-leucyl-L-leucine prepared from solution in methanol. It was found that the sorption of organic compounds, which are able to effective binding with the tripeptide, leads to a significant deformation of L-leucyl-L-leucyl-L-leucine microcrystals on the surface of thin film.

The possibility of using the dipeptide as a working material for gravity sensors used in expert systems for recognition the smell and taste (electronic nose and electronic tongue) are shown.

This work was supported by programs RFBR 09-03-97011-p_volga_region and Federal purpose-oriented program "Scientific and scientific-pedagogical personnel of innovation Russia" for 2009-2013 (Government contract P2345)


PII-78. Thermodynamic Modeling of the Phase Equilibrium of CO2 – Organic Acid Systems with the UMR-PRU Model

Pappa G.1, Louli V.1, Stamataki S.2, Magoulas K.1, Voutsas E.1

1 - School of Chemical Engineering, National Technical University of Athens, Zografou Campus, 15780 Athens, Greece

2 - School of Mining and Metallurgical Engineering, National Technical University of Athens, Zografou Campus, 15780 Athens, Greece

[email protected]

During the last decades the application of supercritical fluid extraction (SFE) in oil and fat industry has been extensively studied, as an attractive alternative to the conventional separation methods. In such applications the knowledge of solubility data is crucial for process design. Especially for fatty acids, such data are quite important since this class of compounds is extensively used in food, pharmaceutical, cosmetic and surfactant industries. Since experimental solubility data are usually limited, due to the difficulties involved (time consuming methods, inaccurate data, etc.), the availability of a reliable predictive model is of great importance.

The recently developed UMR-PRU EoS/GE model, which has been successfully tested to the predictions of different type of phase equilibrium and thermodynamic properties in binary and multi-component systems, is further extended in this work to CO2/fatty acid systems.

New interaction parameters are determined by fitting only vapor-liquid equilibrium data. Using these parameters the UMR-PRU model predicts satisfactorily the vapor-liquid, solid-gas and solid-liquid-gas equilibrium of CO2/fatty acid systems. Furthermore, the UMR-PRU model, with the newly derived interaction parameters, gives very good vapor-liquid equilibrium predictions in ternary mixtures consisting of CO2, organic acids and water.


PII-79. Thermodynamic modelling of mixtures containing antioxidants, organic solvents and ionic liquids

Panteli E., Voutsas E.

School of Chemical Engineering, National Technical University of Athens, 9, Heroon Polytechniou Str., Zographou Campus, 15780 Athens, Greece


Antioxidants are compounds of great interest for the food industry, while they are also widely used in pharmaceutical and biotechnological applications. Ionic liquids (ILs) on the other hand are a relatively new class of solvents that have been the focus of much research in recent years in the scientific community due to some unique properties such as low melting points (<100οC), broad temperature range in which they exist as liquids, high solubilities in them of polar and non-polar organic compounds, as well as of inorganic compounds. Also, due to their very low vapour pressures, near zero emissions in the atmosphere are expected, unlike the volatile organic solvents. On top of that, by simply changing the cation and/or the anion of the IL it is possible to finely tune their intrinsic thermophysical properties making them appropriate for a specific application (designer solvents). In the scope of making ILs attractive for applications in the industry it is important to fundamentally understand their nature and their behavior in the presence of other compounds.

The present study focuses on the thermodynamic modelling of phase equilibrium of mixtures that contain antioxidants, organic solvents and ionic liquids. Illustrative examples presented in this study include: (a) correlation of binary mixtures and prediction of ternary ones using only binary parameters with local composition models; (b) prediction of solubilities of antioxidants in organic solvents with UNIFAC; (c) prediction of antioxidant solubilities in organic solvents and ionic liquids with the COSMO-RS model.


PII-80. Experimental studies of the folding thermodynamics of adsorbed proteins

Choosri T., Wendland M.

Universität für Bodenkultur Wien

[email protected]

The stability of adsorbed proteins is of considerable scientific and technical interest. The stability of proteins in solutions has been studied frequently compared to only few studies on the stability of proteins adsorbed to surfaces. New experimental methods have been developed to measure protein unfolding enthalpies and temperatures with micro DSC calorimetry and the water activity of aqueous solutions by FTIR spectroscopy [1]. DSC studies of the unfolding of the protein have been done for the native solution, the supernatant of the adsorption system and for a mixture of the supernatant and the adsorbant phase. The transition curves of the mixture were regarded as superposition of the curves of the adsorbed protein and that in the supernatant. Thus, the curves of the adsorbed protein can be determined analytically from the supernatant and mixture curves. The FTIR apparatus and method for measuring the water activity aW via the relative humidity described in [1] was improved significantly. The experimental accuracy was tested with humidity fixed points and sodium chloride solutions of varying concentration to be better than 0.001 in aW.

Protein stability in a solution is considered to be mainly a function of the water activity. Protein stability of a protein adsorbed on a surface can be expected to depend strongly on surface properties. Thus, stability and water activity were both measured for lysozyme in aqueous solutions (with HEPES buffer and sodium or calcium chloride) and adsorbed from these solutions on silica nanoparticles. Results show the effect of the addition of sodium and calcium chloride on the unfolding enthalpy and temperature of the protein in solution or the supernatant as function of the water activity. An influence of the kind of salt (sodium or calcium chloride) besides the different water activity on the solved protein stability cannot be seen from the diagrams. The stabilizing effect of adsorption on the protein was also observed whereby the water activity and the change from the monovalent sodium to the bivalent calcium cation have a strong influence on the adsorption and the stability of the protein.

References [1] T. Choosri, G. Koglbauer, M. Wendland, A New Method for the Measurement of the Water Activity or Relative Humidity by Fourier Transform Infrared, J Chem. Eng. Data 54, 1179-1182 (2009).


PII-81. Phase Diagram Studies for Extraction of Alcohols from Azeotropic Mixtures Using Trifluoroethanol at

Atmospheric Pressure

Atik Z., Kerbou W., Kritli A.

Crystallography-Thermodynamics Laboratory, Faculty of Chemistry,University of Sciences and Technology Houari Boumediene,P.O. Box 32 El-Alia, 16114 Bab-Ezzouar, Algiers, Algeria

[email protected]

This study demonstrates the course of solubility and liquid−liquid equilibrium (LLE) for ternary systems (water/hydrocarbon + alcohol + 2,2,2-trifluoroethanol) at different temperatures and pressure 101.3 kPa. The chemicals under investigation were methanol, ethanol, 2-propanol, 1-butanol, hexane, toluene, and cyclohexane.

Measured Tie lines and correlated data by of NRTL and UNIQUAC thermodynamic models where used to construct the phase diagrams.

Estimated interaction parameters for the associated nonpolar-polar systems were used to demonstrate the effect on the system miscibility.

2,2,2-Trifluoroethanol was found efficient to extract alcohols from their hydrocarbon azeotrope at ambient temperatures. The effect of molecular structure of hydrocarbon on extraction process was evaluated.


PII-82. Thermodynamic properties of some α,ω-halogenoalkanes

Chorążewski M.1,2, Grolier J.-P.E.2

1 - Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice, POLAND 2 - Laboratory of Thermodynamics of Solutions and Polymers, University Blaise Pascal,

Clermont-Ferrand, FRANCE

[email protected]

Halogenated hydrocarbons represent an important class of organic compounds. They are used in large quantities as intermediates in organic synthesis, solvents, and refrigerants. This is evidenced also by the organization of three workshops under the auspices of IUPAC on Thermochemical, Thermodynamic and Transport Properties of Halogenated Hydrocarbons and Mixtures in Pisa (1999), Paris (2001), and Rostock (2002).

Formally, halogenated hydrocarbons are usually regarded as products of substitution of one or several H atoms in hydrocarbons by halogen atoms. A better understanding of their properties is achieved by comparing the halogenated hydrocarbon with the hydrocarbon in which each halogen (X) is replaced by a methyl group (CH3). On the one hand C-X bond dipole is fairly large for X = F and decreases slightly in the series F > Cl > Br > I. On the other hand the polarizabilities, hence the dispersion forces, increase considerably in the series F < Cl < Br < I.

α,ω-Halogenoalkanes are polar nonassociated liquids, in which important electrostatic intermolecular interactions occur due to nonzero permanent dipole moments and/or quadrupole moments [1]. In addition, these are compounds characterized by the so-called intramolecular proximity effect [2], that is, a change in the distance between two halogen atoms in the molecule induces a change in the behavior and therefore on the interaction parameters with other functional groups.

The heat capacities, speeds of sound, and densities as functions of temperature and pressures and their derivatives allow a documented insight into the molecular structures of liquids and consequently yield quantitative evaluation of intermolecular interactions. Unfortunately, basic properties of α,ω-dibromoalkanes and their mixtures with n-alkanes, such as heat capacities, densities, and speeds of sound at atmospheric pressure as well as under elevated pressures are rather scarce in the literature. This prompted us to continue our earlier calorimetric and acoustic study of pure halogenoalkanes [3-5] and their mixtures with aliphatic alkanes [6-8] and to expand it onto speeds of sound measurements under elevated pressures [9].

The present work contributes to a better knowledge and understanding, not only of the properties and molecular interactions in bromoalkanes/chloroalkanes, but also of the whole class of halogenated hydrocarbons.


References

1. G. Khanarian and A.E. Tonelli, A Kerr effect and dielectric study of α,ω -dibromoalkanes. J. Chem. Phys. 75, 5031 (1981). 2. H.V. Kehiaian, Group contribution methods for liquid mixtures: a critical review. Fluid Phase Equilib., 13, 243 (1983). 3. S. Ernst, M. Chorążewski, M. Tkaczyk, P. Góralski, Heat capacities and densities of α,ω-dibromoalkanes as functions of temperature. A group additivity analysis. Fluid Phase Equilib., 174, 33 (2000). 4. P. Góralski, M. Tkaczyk, M. Chorążewski, DSC measurements of heat capacities of α,ω-dichloroalkanes within the temperature range from 284.15 K to 353.15 K. A group additivity analysis. J. Chem. Eng. Data, 48 (3), 492 (2003). 5. M. Chorążewski, P. Góralski, M. Tkaczyk, Heat capacities of 1-chloroalkanes and 1-bromoalkanes within the temperature range from 284.15 K to 353.15 K. A group additivity and molecular connectivity analysis. J. Chem. Eng. Data, 50, 619 (2005). 6. M. Chorążewski, M. Tkaczyk, Heat capacity, speed of ultrasound, and density for 1,5-dibromopentane + heptane within the temperature range from 293.15 K to 313.15 K. J. Chem. Eng. Data, 51, 1825 (2006). 7. M. Chorążewski, Thermophysical and acoustical properties of the binary mixtures 1,2-dibromoethane + heptane within the temperature range from 293.15 K to 313.15 K. J. Chem. Eng. Data, 52, 154 (2007). 8. M. Chorążewski, P. Góralski, M. Hrynko, J.-P. E. Grolier, E. Wilhelm, Thermodynamic and acoustic properties of mixtures of 1,6-dichlorohexane with heptane from (293 – 313) K. J. Chem. Eng. Data, 55, 5471 (2010). 9. M. Chorążewski, M. Skrzypek, Thermodynamic and acoustic properties of 1,3-dibromopropane and 1,5-dibromopentane within the temperature range from 293 K to 313 K and pressures up to 100 MPa. International Journal of Thermophysics, 31, 26 (2010).


PII-83. Corrosion of copper in 1-alkyl-3-methylimidazolium tetrafluoroborates contaminated with water and chlorides

Marczewska-Boczkowska K., Kosmulski M.

Lublin University of Technology, Nadbystrzycka 38, 20-618 Lublin, Poland

[email protected]

The low-temperature ionic liquids have been considered as attractive solvents for organic synthesis, electrochemical devices, and as lubricants and heat-transfer media. These applications imply contact of ionic liquids with metals including copper and its alloys. A series of 1-alkyl-3-methylimidazolium tetrafluoroborates was studied with respect of their reaction with metallic copper. Short-chain 1-alkyl-3-methylimidazolium tetrafluoroborates are more corrosive than their long-chain analogs, and the presence of impurities (water, chlorides, and especially simultaneous presence of both) substantially enhances the pitting corrosion. Interestingly enough, pre-treatment of copper in hot (>150 oC) pure ionic liquids produces a protective layer, which prevents corrosion and room temperature. The elementary composition of corrosion products of Cu obtained in various ionic liquids (pure and contaminated) and at various temperatures (up to 200 oC) has been studied.


AUTHOR INDEX


A

Aase B.Ø. ..................................................... 129 Aaserud C..................................................... 129 Abdulagatov I. ...................................... 120, 321 Aguilar F....................................................... 361 Aim K................................................... 387, 389 Akhavan-Behabadi M.A............................... 371 Alaoui F. ....................................................... 361 Albers K. ...................................................... 159 Alevizou E...................................................... 45 Alvim-Ferraz M.C.M. .......................... 285, 286 Anisimov M.A........................................ 34, 281 Arce A. ......................................... 403, 404, 405 Arlt W. ...................................... 22, 57, 103, 248 Arpentinier Ph. ............................................. 178 Atake T. ........................................................ 106 Atik Z. .......................................................... 420 Auger E. ....................................................... 161

B

Babaee S. ...................................................... 170 Balankina E.S. .............................................. 369 Ballerat-Busserolles K............................ 18, 234 Bardow A........................................................ 30 Barthen P. ..................................................... 330 Baudouin O. ......................................... 178, 347 Belandria V. .................................................. 171 Bendová M. .................................................. 387 Bernard O. .................................................... 257 Bernatová S. ................................................. 303 Bernhardt E. ................................................. 330 Bittencourt S.S. ............................................ 328 Blas F............................................................ 118 Blokhin A.V. ......................................... 229, 233 Bobák M....................................................... 247 Bogatishcheva N.S. ...................................... 339 Bogatu C....................................................... 115 Bogdanić G. .......................................... 301, 304 Bölts R.......................................................... 276 Bonarska-Kujawa D. .................................... 341 Bonilla-Petriciolet A..................................... 335 Borówko M. ......................................... 297, 298 Bottini S.B...................................................... 25 Bouchafaa W. ................................................. 69 Bougrine A.J................................. 373, 375, 376 Boutin A. ...................................................... 310 Braeuer P. ............................................. 316, 317 Breure B. ...................................................... 306 Brignole E.A..........................................113, 337

Brodskaya E.N. .............................207, 254, 256 Builes S. ..........................................................91 Bukharaev A.A..............................................415 Burger A.J. ....................................................165 Burov S.V......................................................205

C

Cabañas A. .................................................... 411 Cabeza O.......................................................384 Caceres J. ........................................................35 Calvar N................................................215, 217 Cambar J. ........................................................ 11 Campagnoli S................................................260 Cao B.-Y..........................................................75 Carneiro A.P. .................................................209 Camy S..........................................................355 Carrier H. ......................................................241 Carvalho P.J. .................................................225 Cassens J. ......................................................109 Cassiède M............................................239, 241 Cezac P.................................................... 11, 178 Chamorro C.R.......................................363, 364 Chirico R.D...........................................120, 321 Chirkst D.E. ..................................................237 Chislov M.V. .................................................231 Chmelař J. ...............................................53, 243 Choosri T.......................................................419 Chorążewski M. .................................... 119, 421 Christensen K.O....................................129, 131 Chuklanov A.P. .............................................415 Cismondi Duarte M.......................127, 365, 366 Cocchi G........................................................264 Comuñas M.J.P. ............................................227 Condoret J.-S. ...............................................355 Constantinescu D.G...............................276, 318 Contamine F. ........................................... 11, 178 Coto B...........................................................359 Coulier Y. ................................................18, 234 Counioux J.J..................................................375 Coussine C. ..................................................... 11 Coutinho J.A.P. .............................221, 223, 225 Coxam J.-Y..............................................18, 234 Creton B........................................................312 Cristino A.F. ..................................................163 Cummings P.T. ................................................82

D

Dalirian M.......................................................83 Dalmazzone D.................................................69


Daridon J.L............................238, 239, 240, 241 Dávila J........................................................... 35 De Angelis M.G. ............101, 260, 262, 264, 266 De Azevedo E.G. .......................................... 107 De Hemptinne J.-C. .......................................... 5 De Loos T.W................................................. 115 De Souza W.L.R. .......................................... 356 De Villiers A.J. ............................................. 165 Déchelotte S. ................................................ 347 Deenadayalu N. ............................................ 198 Dehghani M.R. ............................................... 83 Delalu H. ...................................................... 373 Deublein S. ..................................................... 71 Dhenain A..................................... 373, 375, 376 Di Nicola G................................................... 282 Diky V................................................... 120, 321 Dobrovicescu A. ........................................... 325 Docherty H. .................................................... 82 Doghieri F..................................... 101, 260, 264 Dohrn R. ................................................... 5, 393 Domańska-Żelazna U.M...39, 41, 192, 193, 194,

195, 197 Domingo C. .................................................... 91 Domínguez A........................................ 215, 217 Domínguez-Pérez M..................................... 384 Dong L.......................................................... 351 Dorn U.................................................... 55, 252 Drach M........................................ 269, 271, 272 Duarte T. ....................................................... 107 Dubourg K...................................................... 11 Duchet-Suchaux P......................................... 312 Duvančić M. ................................................. 378 Dzhevaga N.A. ............................................. 237

E

Economou I. ..................................................... 5 Economou I.G........................................211, 306 Efimova A. ................................................... 353 Efimova I.G. ................................................. 415 Elliott J.R........................................................ 72 Elwardany A. .................................................. 75 Emel'yanenko V.N. ................................. 47, 398 Enders S.......................................... 55, 250, 252 Enke D.......................................................... 316 Escandell J.................................................... 125 Eslamimanesh A. ...166, 167, 168, 169, 170, 171 Espada J.J. .................................................... 359 Etherington G................................................ 155

F

Fele Žilnik L..................................................... 5 Fernandez E.J. ................................................ 59

Fernández J. ....................................49, 225, 227 Feroiu V.........................................................395 Ferrando M. ..................................................310 Figueiras A.O. ...............................................413 Filipe E.J.M........................................... 118, 163 Finkelshtein E. ..............................................266 Fischer K.......................................................147 Francisco M. ...........................................94, 403 Frangieh M.R. ...............................373, 375, 376 Frenkel M......................................120, 321, 322

G

Gaciño F.M. ..................................................227 Galindo A..................................................6, 163 Galizia M. .....................................................266 Gani R. ..........................................................121 Garrido N.M.................................................. 211 Geana D. ....................................................... 115 Geană D. .......................................................395 Gerlach T.........................................................32 Gharagheizi F. ...............................................169 Ghobadi A.F. ...................................................72 Girbasova N.V...............................................258 Gmehling J............................ 141, 276, 318, 319 Gómez E. ..............................................215, 217 González E.J. ................................................217 Gonzalez Prieto M. .........................................25 Goodrich P.....................................................203 Gor G.Yu. ......................................................274 Gorbatchuk V.V.............................................415 Gordillo D. ....................................................349 Goutaudier C.........................................375, 376 Gregor T. .......................................................243 Grolier J.-P.E......................................... 119, 421 Grosu L. ........................................................325 Grunwaldt J.-D..............................................181 Gusev I.G. .......................................................75

H

Hajali N.........................................................314 Hájová H. ................................................53, 243 Hardacre C. ...................................................203 Hashemi H. ...................................................170 Hasse H. ..................................................71, 273 Haugum T......................................................131 Hauk D.B. .....................................................329 Haverkampf V. ..............................................393 Hegel P.E....................................................... 113 Heikal M.R......................................................75 Heilig M........................................................159 Heintz A. .................................................47, 154 Hempel S. .......................................................62


Hendriks E................................................ 5, 147 Heuchel M. ................................................... 101 Hodaj F. .......................................................... 81 Hofman T...................................................... 189 Hofmann D................................................... 101 Hoga H.E...................................................... 327 Horsch M........................................................ 85 Houssin-Agbomson D. ................................. 178 Hovorka S....................................................... 40 Hrkovac M.................................................... 378 Huber M.L. ................................................... 322 Hukkerikar A. ............................................... 121 Hwang S.Y.................................................... 332 Hy-Billiot J. .................................................. 312

I

Idrisova S...................................................... 283 Ignatiev N.V.................................................. 330 Ingram T. ........................................................ 32 Izadpanah A.A. ............................................. 291 Izák P. ............................................................. 40

J

Jackson G........................................................ 85 Jaouahdou A. ................................................ 284 Jaubert J.-N....................132, 399, 400, 407, 408 Javanmardi J. ................................................ 170 Jorge M......................................................... 211 Jovanović S.M. ............................................. 304 Jung N. ........................................................... 67

K

Kacirkovák M................................................. 40 Kaleng C....................................................... 198 Kalies G. ............................................... 316, 317 Kamaltdinov I............................................... 283 Kato S........................................................... 391 Kazakov A. ................................... 120, 321, 322 Kędra-Królik K............................................. 407 Kerbou W...................................................... 420 Kleszczyńska H. ........................................... 341 Kocherbitov V................................................. 99 Kohut S.V. ............................................ 229, 233 Koneva A.S..................................................... 43 Konstantinova N.M. ..................................... 289 Kontogeorgis G.M. ......5, 19, 185, 131, 179, 181 Koroleva S.V. ............................................... 172 Kosek J. .................................. 53, 243, 245, 247 Kosmulski M. ......................................... 87, 423 Kostko A.F.................................................... 104 Kovaleva L. .................................................. 283

Kritli A. .........................................................420 Kroenlein K...........................................120, 321 Królikowska M. ....................................192, 197 Kroon M.C. ...................................................308 Kulaguin – Chicaroux A. ................................55

L

Lachet V. .......................................134, 310, 312 Lago S. ..........................................................405 Lampreia I.M.S. ............................152, 413, 414 Langa E. ........................................................203 Le Parlouër P.................................................155 Le Roux D.....................................................312 Lerche B.M. ..................................................187 Letourneau J.-J..............................................355 Li J. ...............................................................351 Likhatsky V.V................................................174 Lin S.-Y.........................................................190 Linek J. .........................................................386 Lisal M............................................................27 Litvinova T.E. ...............................................237 Liu X...............................................................30 Llovell F. .................................................67, 279 Lobacheva O.L..............................................237 Lobanova O.....................................................22 Loglio G. .......................................................190 Løkken T.V............................................129, 131 Lopatin S.I. ...................................................296 López-Aranguren P. ........................................91 Louli V. .........................................................417 Lourenço M.J.V......................... 16, 20, 152, 203 Lucile F. ........................................................178 Łuczyński J. ..........................................341, 343 Lugo L. ...................................................49, 225 Luis P. ...........................................................409

M

Mabe J........................................................... 113 Macedo E.A. ... 60, 209, 211, 213, 215, 217, 219 Macura R.......................................................323 Mączka E. .......................................................87 Magee J.W.............................................120, 321 Magoulas K...................................................417 Maitland G.C. ................................................ 116 Majlesi K. .....................................................314 Makowska A. ................................................380 Mamontov M.N. ...........................................289 Manic M.S. ...................................................219 Marciniak A. .........................................193, 197 Marcos R.M. .................................................279 Marczewska-Boczkowska K.........................423 Maribo-Mogensen B. ....................................179


Marinichev A.N. ........................................... 299 Markelov D. ................................................. 202 Martín M.C........................................... 363, 364 Martins F.G. .................................. 285, 286, 288 Martins L.F.G................................................ 118 Martos C....................................................... 359 Matijašić G.................................................... 378 Matkowska D. .............................................. 189 Matos H.A. ................................................... 107 Mattea F........................................................ 308 McCabe C..................................................... 118 McHugh M.A. .............................................. 104 Mehling T. ...................................................... 32 Melnyk R........................................................ 74 Memari P. ..................................................... 134 Mendes M.F.................................................. 356 Merker T. ...................................................... 273 Michelsen M................................................. 185 Mićić V. ........................................................ 323 Mikhailovskaya A.A..................................... 190 Milanesio J.M............................................... 365 Miller R. ....................................................... 190 Minelli M.............................................. 101, 260 Miroshnichenko S........................................... 85 Missyul A.B.................................................. 233 Moglie M...................................................... 282 Mohammadi A.H. ..166, 167, 168, 169, 170, 171 Mohseni S.G. ................................................ 371 Moise J.-C. ................................................... 408 Moita M.L.C.J. ..................................... 413, 414 Mokrushina L. .................................. 22, 57, 248 Moncada M. ................................................... 35 Mondéjar M.E. ............................................. 364 Montel F. ...................................................... 238 Montero E.A................................................. 361 Montes A. ..................................................... 349 Morávková L. ....................................... 386, 389 Moreira C.M................................................. 356 Morère J........................................................ 411 Morgado P..............................................118, 163 Morice R....................................................... 398 Moskvin P.P. ................................................. 345 Mota F.L. ........................................................ 60 Moucka F........................................................ 27 Mougin P. ..................................................... 312 Mudzhikova G.V. .......................................... 256 Muhr H. ........................................................ 284 Müller E.......................................................... 85 Müller K. ........................................................ 22 Musko N.E. .................................................. 181 Mutelet F............................................... 407, 408 Muzny C.D. .................................. 120, 321, 322

N

Najdanovic-Visak V. .....................................219 Narkiewicz-Michałek J. ................269, 271, 272 Neau E. .........................................................125 Nezbeda I. .......................................................74 Nichita D.V. ..................................................136 Nicolas C. .....................................................125 Niedziółka K. ................................269, 271, 272 Nieto De Castro C.A. .............. 16, 152, 163, 203 Nikbakht F.....................................................291 Nikitin E.D....................................................339 Niño-Amézquita G. .......................................250 Nistor A...................................................53, 243

O

Obraztsova E.D. ............................................242 O'Connell J.P...................................................59 Okubo N................................................401, 402 Olchowik G. ..................................................345 Olchowik J.M................................................345 Oliveira M.B. ................................221, 223, 225 Ovesen R.V. ..................................................129

P

Pacciani R. ......................................................91 Padrela L. ......................................................107 Paduszyński K.................................39, 192, 193 Pagel R..........................................................398 Paillol H. .......................................................239 Paillol J.H......................................................241 Palavra A.M.F. ..............................................163 Palmeiro I......................................................404 Pando C......................................................... 411 Panteli E........................................................418 Pappa G. ........................................................417 Paredes X. .....................................................227 Paricaud P................................................69, 161 Park K. ..........................................................332 Park Y.K........................................................332 Parvez A........................................................409 Passarello J.P.................................................161 Pauly J...........................................239, 240, 241 Pavlíček J. .....................................................303 Pejović B.......................................................323 Pelczarska A..........................................194, 195 Peña J.L.........................................................359 Penkova A. ....................................................202 Peper S. .........................................................393 Pereda S. ......................................... 25, 113, 337 Pereyra C.......................................................349 Perles C.E......................................................410


Peters C.J. ..................................... 151, 306, 308 Pinheiro L.M.V. ............................................ 413 Pinho S.P......................................................... 60 Pires J.C.M. .................................. 285, 286, 288 Pisoni G.O..................................................... 366 Pobudkowska A.................................... 194, 195 Pokorný R....................................................... 53 Polishuk I...................................................... 333 Polotskaya G. ................................................ 200 Ponte M.N. ................................................... 219 Poot W. ......................................................... 115 Poźniak R. ............................................ 341, 343 Prikhodko I.V................................................ 276 Privat R......................................... 132, 399, 400 Prlić Kardum J.............................................. 378 Próchniak P. .................................................... 87 Prudic A........................................................ 109 Pukinsky I.B. ................................................ 276 Pulyalina A. .................................................. 200

Q

Qian J.................................................... 399, 400 Queimada A.J. .................60, 211, 219, 221, 223 Queirós C.S.G.P. ............................................. 20

R

Ralys R. .......................................................... 47 Ramirez R....................................................... 91 Ramjugernath D. .................................. 194, 198 Randová A. ..................................................... 40 Rarey J.......................................................... 319 Reddy P......................................................... 198 Regueira T. ............................................. 49, 225 Reichenbach C.............................................. 316 Reis J.C.R..................................................... 413 Reiser S. ......................................................... 71 Reneaume J.-M............................................... 11 Renuncio J.A.R............................................. 411 Riaz M. ......................................................... 131 Ribeiro A.P.C.......................................... 16, 203 Ribeiro V....................................................... 223 Richet P......................................................... 106 Richon D. ......................166, 167, 168, 169, 171 Rilo E............................................................ 384 Robustillo M.D............................................. 359 Rochelle P. .................................................... 325 Rodier L.................................................. 18, 234 Rodil E.......................................................... 404 Rodrigues H.................................................. 118 Rodrigues M................................................. 107 Rodríguez H. ................................................ 405 Rodríguez J.F.................................................. 13

Rodríguez O..........................................209, 213 Rodríguez Reartes S.B. .................127, 365, 366 Rodríguez-Cabo B. ...............................403, 404 Rosa S.C.S. ...................................................163 Rosales-Candelas I........................................335 Rosenholm J.B. ...............................................87 Rotrekl J........................................................387 Rousseau B. ..................................................134 Ruck M. ........................................................353 Ruether F.......................................................109 Rumyantsev A.......................................401, 402 Rusanov A.I. .......................................7, 79, 278

S

Sadegh N.........................................................19 Sadowski G. ....................................62, 109, 159 Safi M.J.........................................................284 Safieva J.O. ...................................................176 Safonova E.A. .................................................43 Saito K. .........................................................150 Sánchez F.A. .................................................337 Sánchez P. .......................................................13 Sánchez-Silva L. .............................................13 Sandersen S.B. ..............................................183 Sankovich A.M. ............................................229 Santos A.F.S. .........................................413, 414 Sarge S.M......................................................398 Sarti G.C................................ 101, 260, 262, 266 Sarup B. ........................................................121 Sazhin S.S. ......................................................75 Schauer J. ........................................................40 Schick C..........................................................47 Schmid B. .....................................................141 Schmidt P. .....................................................353 Schrader P. ......................................................55 Schrey A........................................................147 Schwarz C.E..................................................165 Secuianu C. ........................................... 116, 395 Šeda L. ..................................................245, 247 Sedláková Z. .................................386, 387, 389 Segade L. ......................................................384 Segovia J.J. ...................................361, 363, 364 Semashko O.V...............................................254 Serin J.-P. ........................................................ 11 Shapovalova A.A. .................................205, 207 Shchekin A.K. ...........................................79, 85 Shilov A.L.....................................................296 Shishkova I.N..................................................75 Shugurov S.M. ..............................................296 Sienkiewicz A. ..............................269, 271, 272 Silva J.F.C.C. ................................................414 Silvério S.C...................................................213


Silyukov O.I. ................................................ 231 Simões M.............................................. 285, 286 Simond M............................................... 18, 234 Simonin J.P. ............................................ 28, 257 Sin G. ............................................................ 121 Singh J.K. ....................................................... 82 Siporska A. ................................................... 382 Sizov V.V. ............................................. 205, 207 Skouras E...................................................... 129 Skrzypczak A................................................ 408 Smirnova I. ............................................... 32, 93 Smirnova N.A......................................... 43, 276 Smith W.R. ..................................................... 27 Smolná K...................................................... 243 Snegirev A.Yu................................................. 75 Soares R.B.................................................... 356 Sokolova E.P................................................. 299 Sokolowski A. .............................................. 343 Sokołowski S........................................ 297, 298 Solbraa E. ............................................. 129, 131 Soria T.M........................................................ 25 Soto A........................................... 403, 404, 405 Soto-Bernal J.J.............................................. 335 Sponsel E................................................ 57, 248 Srivastava R.................................................... 82 Stamataki S................................................... 417 Staszewski T. ........................................ 297, 298 Stenby E.H.......................19, 131, 183, 185, 187 Stolyarova V.L. ..................................... 295, 296 Subramanian D. ............................................ 281 Sun G. ........................................................... 351 Syunyaev R.Z. ...................................... 174, 176 Szydłowski J......................................... 380, 382 Szymula M. .................................. 269, 271, 272

T

Tachibana H.................................................. 391 Tadie M. ....................................................... 198 Tahooneh A................................................... 166 Takada A....................................................... 106 Tatyanenko D.V. ............................................. 79 Teixeira J.A. ................................................. 213 Tenu R. ................................................. 375, 376 Thomsen K. .................................... 19, 179, 187 Tisma M. ........................................................ 40 Tobaly P. ....................................................... 161 Toikka A. .............................................. 200, 202 Toikka M.A. ......................................... 235, 237 Torine G.A. ................................................... 363 Tôrres R.B. ................................... 327, 328, 329 Torres-Arenas J............................................. 257 Trofimova M.A............................................. 235

Trokhymchuk A. .............................................74 Trusler J.P.M. ........................................ 116, 142 Tsivintzelis I..........................................181, 185 Tsvetov N.S...................................................235 Tsyrulnikov S.A. ...........................................258

U

Untea A. ........................................................325 Uspenskaya I.A. ............................................289

V

Vacher A........................................................347 Valbuena V. ...................................................240 Valente E. ........................................................67 Van Der Bruggen B.......................................409 Varaminian F. ................................................291 Varela L.M. ...................................................384 Varet G...........................................................238 Vargas F.M. ...................................................306 Vega L.F. ...........................................67, 91, 279 Vélez A. ........................................................ 113 Venediktova A.V. ..........................................242 Verevkin S.P. ...........................................47, 398 Vesovic V. .........................................................5 Victorov A.I. .........................................172, 258 Vieira S.I.C. ......................................16, 20, 203 Vila J. ............................................................384 Vilaseca O. ..............................................67, 279 Villamañán M.A............................361, 363, 364 Villamañán R.M....................................363, 364 Vlasov A.Yu. .................................................242 Vlugt T.J.H......................................................30 Völkl J...........................................................103 Volle F. ..........................................................161 Volpe P.L.O. ..........................................327, 410 Von Solms N.S. .............................................183 Vonka M........................................................245 Vorobyov E.N. ..............................................276 Voutsas E................................. 45, 149, 417, 418 Vrabec J.............................................71, 85, 273 Vrbka P..........................................................387

W

Wagner Z...............................................386, 389 Wendland M..................................................419 Westerholt A..................................................147 Wichterle I. ...........................................301, 303 Wilk K...........................................................341 Wille S. ...........................................................57 Willner H. .....................................................330 Witek S..........................................................341


Wolf H. ......................................................... 398 Wu X. ........................................................... 351

X

Xie J.-F. .......................................................... 75

Y

Yakovleva M.A............................................. 276 Yamamura Y. ................................................ 150 Yampolskii Y.P.............................................. 266 Yan W. .......................................................... 131 Yazdizadeh M............................................... 166

Z

Zabaloy M.S..................................127, 365, 366 Zacur Martínez J.L........................................367 Zahran F. ....................................................... 411 Zaitsau Dz.H. ..........................................47, 398 Zawadzki M. ...................................................41 Zheng D. .......................................................351 Ziganshin M.A. .............................................415 Ziganshina S.A..............................................415 Zubov A. .......................................................247 Zvereva I.A. ..................................229, 231, 233


LIST OF PARTICIPANTS


Algeria Prof. Atik, Zadjia University of Sciences and Technology Houari Boumédiène, USTHB Department of Chemistry Algiers 16114 Bab Ezzouar B.O;Box 32 Al-Alia [email protected] Argentina Prof. Brignole, Esteban PLAPIQUI, Department of Chemical Engineering Bahía Blanca 8000 Camino La Carrindanga km 7.5 [email protected] Dr. Cismondi Duarte, Martin UNC – CONICET Chemical Engineering – IDTQ Córdoba X5016GCA Av. Vélez Sársfield 1611 [email protected] Ph.D. Pereda, Selva Planta Piloto de Ingeniería Química Universidad Nacional del Sur Bahía Blanca 8000 Camino La Carrindanga km 7 [email protected] Dr. Zacur Martínez, Jose Luis Universidad Nacional de Jujuy Facultad de Ingeniería Jujuy 4600 Gorriti 237 [email protected]

Austria Prof. Wendland, Martin Universität für Bodenkultur Wien Institut für Verfahrens- und Energietechnik Vienna 1190 Muthgasse 107 [email protected] Belarus Prof. Blokhin, Andrey Belarusian State University Chemistry Faculty Minsk 220030 Leningradskaya 14 [email protected] Belgium Dr. Luis, Patricia K.U.Leuven Department of Chemical Engineering Leuven 3001 W. de Croylaan 46 [email protected] Bosnia and Herzegovina Mr. Mićić, Vladan Faculty of Technology Department of Chemical Engineering Zvornik 75400 Karakaj bb [email protected]


Brazil Mrs. Mendes, Marisa UFRRJ, Department of Chemical Engineering Seropédica 23890-000 BR 465 - km 7 [email protected] Dr. Tôrres, Ricardo Centro Universitario da FEI Departamento de Engenharia Quimica São Bernardo do Campo - São Paulo 9850901 Avenida Humberto de Alencar Castelo Branco 3972 Bairro Assunção [email protected] Prof. Volpe, Pedro Universidade Estadual de Campinas Departamento de Físico-Química Campinas 13083-970 Cidade Universitária Zeferino Vaz [email protected] Canada Mr. Smith, William University of Ontario Institute of Technology Faculty of Science Oshawa L1h 7K4 2000 imcoe Street North [email protected] China Prof. Zheng, Danxing Beijing University of Chemical Technology Department of Chemical Engineering Beijing 100029 Heping Street [email protected]

Colombia Mr. Dávila, Javier Department of Chemical Engineering Bogota 1111 Carrera 1E No. 19A-40 [email protected] Croatia Prof. Prlić Kardum, Jasna Faculty of chemical engineering and technology Department of Mechanical and Thermal Process Engineering Zagreb 10000 Marulićev trg 20 [email protected] Czech Republic Dr. Aim, Karel Institute of Chemical Process Fundamentals ASCR E. Hala Laboratory of Thermodynamics Prague 16502 Rozvojová 135, Praha 6 [email protected] Ph.D. Izák, Pavel Institute of Chemical Process Fundamentals, Academy of Sciences CR Department of Separation Processes Prague 16502 Rozvojová 135, Praha 6 [email protected] Dr. Kosek, Juraj Institute of Chemical Technology, Prague Department of Chemical Engineering Prague 16628 Technická 5 [email protected]


Mr. Linek, Jan Institute of Chemical Process Fundamentals of the ASCR, v.v.i. E. Hála Laboratory of Thermodynamics Prague 16502 Rozvojová 135, Praha 6 [email protected] Ms. Morávková, Lenka Institute of Chemical Process Fundamentals of the ASCR, v. v. i. E. Hála Laboratory of Thermodynamics Prague 16502 Rozvojová 135, Praha 6 [email protected] Prof. Nezbeda, Ivo J. E. Purkinje University Department of Chemistry Ústí n. L. 400 96 České mládeže 8 [email protected] Ms. Sedláková, Zuzana Institute of Chemical Process Fundamentals of the ASCR, v.v.i. Prague E. Hála Laboratory of Thermodynamics Prague 16502 Rozvojová 2, Prague 6 [email protected] Ms. Smolná, Klara Institute of Chemical Technology Prague Department of Chemical Engineering Prague 16628 Technická 5, Prague 6 [email protected] Mr. Vonka, Michal Institute of Chemical Technology Prague Department of Chemical Engineering Prague 16628 Technická 5 Prague 6 Dejvice [email protected]

Dr. Wichterle, Ivan Institute of Chemical Process Fundamentals E. Hála Laboratory of Thermodynamics Prague 16502 Rozvojová 135, Praha 6 [email protected] Mr. Zubov, Alexandr Institute of Chemical Technology Prague Department of Chemical Engineering Prague 16628 Technická 5 [email protected] Denmark Mr. Hukkerikar, Amol Technical University of Denmark CAPEC, Chemical and Biochemical Engineering Copenhagen 2800 Room No. 214, Building 227, CAPEC, DTU [email protected] Prof. Kontogeorgis, Georgios Technical University of Denmark Department of Chemical and Biochemical Engineering Lyngby DK-2800 Building 229 [email protected] Ms. Lerche, Benedicte DTU (Technical University of Denmark) Department of Chemical and Biochemical Engineering Kgs. Lyngby 2800 Søltofts Plads, Building 229, room 206 [email protected]


Mr. Maribo-Mogensen, Bjørn Center for Energy Resources Engineering (CERE) Department of Chemical and Biochemical Engineering, Technical University of Denmark (DTU) Kgs. Lyngby 2800 Søltofts Plads, Bygning 229, Rum 254 [email protected] Mr. Musko, Nikolai Technical University of Denmark, DTU Department of Chemical and Biochemical Engineering Lyngby 2800 DTU, Building 229, room 116 [email protected] Mr. Riaz, Muhammad Technical University of Denmark Center for Energy Resources Engineering (CERE), Department of Chemical and Biochemical Engineering Lyngby 2800 Kgs Søltofts Plads, Building 229, Room 210 [email protected] Mrs. Sadegh, Negar Technical University of Denmark Department of Chemical and Biochemical Engineering Kgs. Lyngby 2800 Søltofts Plads, Building 229, room 206 [email protected] Mrs. Sandersen, Sara Center for Energy Resources Engineering Department of Chemical & Biochemical Engineering Kgs. Lyngby DK-2800 Søltofts Plads, Build. 229/Room 240 [email protected]

France Mr. Auger, Eric LSPM, Université Paris 13 Villetaneuse 93430 99 avenue Jean-Baptiste Clément [email protected] Dr. Ballerat-Busserolles, Karine LTIM - UMR6272 Department of Chemistry Clermont-Ferrand 63177 24 avenue des Landais [email protected] Mr. Baudouin, Olivier ProSim Process Labege F-31672 Stratege Batiment A BP 27210 [email protected] Dr. Camy, Severine Université de Toulouse ; INPT, UPS Laboratoire de Genie Chimique Toulouse F-31030 4, Allée Emile Monso [email protected] Dr. Condoret, Jean-Stephane Université de Toulouse ; INPT, UPS Laboratoire de Genie Chimique Toulouse F-31030 4, Allée Emile Monso [email protected] Ms. Coussine, Charlotte LaTEP, High pressure group PAU Cedex 64000 rue Jules Ferry BP 7511 [email protected]


Mr. Daridon, Jean Luc Université de Pau Laboratoire des Fluides Complexes Pau 64013 BP 1155 [email protected] Mrs. Dhenain, Anne Université Claude Bernard Lyon 1/CNRS Department of Chemistry Villeurbanne F-69622 Bâtiment Berthollet 3e, 22 avenue Gaston Berger [email protected] Mr. Escandell, Joan University of Méditerranée Department of Physical Chemistry Marseille 13009 163 Avenue de Luminy, Case 901 [email protected] Mr. Eslamimanesh, Ali Mines ParisTech Department of Energy and Process Fontainebleau 77305 35 rue Saint Honoré [email protected] Dr. Etherington, Gary SETARAM Instrumentation Caluire 69300 7 Rue de l’Oratoire [email protected] Mr. Ferrando, Nicolas IFP Energies nouvelles Department of Thermodynamics and Molecular Modeling Rueil-Malmaison 92852 1-4 Avenue de Bois Préau [email protected]

Mrs. Frangieh, Marie-Rose Université Claude Bernard Laboratoire Hydrazines et Procédés Lyon 69622 22, avenue Gaston Berger [email protected] Mrs. Goutaudier, Christelle Université Claude Bernard Lyon 1 Laboratoire Multimateriaux et Interfaces VILLEURBANNE cedex 69622 43, Bd 11 Novembre [email protected] Mrs. Grosu, Lavinia University of Paris Ouest Laboratoire Energétique, Mécanique et Electromagnétisme Ville d’Avray 92410 50, rue de Sèvres [email protected] Prof. Hodaj, Fiqiri Grenoble Institute of Technology, SIMAP Grenoble 38402 SIMAP Domaine Universitaire BP 75 38402 Saint Martin d’Hères France [email protected] Prof. Jaubert, Jean-Noël Nancy-Université ENSIC-LRGP Nancy 54000 1 rue Grandville [email protected] Dr. Lachet, Véronique IFP Energies nouvelles Applied Chemistry and Physical Chemistry Department Rueil-Malmaison 92852 1-4 avenue de Bois Préau [email protected]


Ms. Lucile, Floriane LaTEP High pressure group Pau cedex 64075 rue Jules Ferry BP 7511 [email protected] Prof. Neau, Evelyne University of Méditerranée Department of Physical Chemistry Marseille 13009 163 Avenue de Luminy, Case 901 [email protected] Prof. Nichita, Dan Vladimir University of Pau Complex Fluid Laboratory Pau 64013 BP 1155 [email protected] Mr. Nicolas, Christophe University de la Méditerranée Institut Universitaire de Technologie La Ciotat 13708 Avenue Maurice Sandral [email protected] Dr. Paricaud, Patrice ENSTA-ParisTech Department of Chemical Engineering Paris 75739 ENSTA, UCP, 32 Boulevard Victor, 75739 Paris cedex 15, France [email protected] Mr. Pauly, Jerome Université de Pau Laboratoire des Fluides Complexes Pau 64000 Avenue de l’Université [email protected]

Mr. Rousseau, Bernard CNRS, Department of Physical Chemistry Orsay 91405 Laboratoire de Chimie Physique, Bâtiment 349, Université Paris-Sud 11 [email protected] Ph.D. Simond, Mickael LTIM-UMR 6272 Chemistry Department Clermont-Ferrand 63177 24 Avenue des Landais [email protected] Prof. Simonin, Jean-Pierre University P.M. Curie Department of Chemistry Paris 75005 Laboratoire PECSA Case 51, 4 Place Jussieu [email protected] Mr. Varet, Guillaume TOTAL EP/SCR/PJ Pau 64000 avenue de Larribau [email protected] Dr. Volle, Fabien LSPM, Université Paris 13 Villetaneuse 93430 99, avenue J.-B. Clément [email protected] Germany Ms. Albers, Katja TU Dortmund, Laboratory of Thermodynamics Biochemical and Chemical Engineering Dortmund 44227 Emil-Figge-Straße 70 [email protected]


Mr. Cassens, Jan TU Dortmund, Laboratory of Thermodynamics Biochemical and Chemical Engineering Dortmund 44227 Emil-Figge-Straße 70 [email protected] Dr. Constantinescu, Dana Gabriela University of Oldenburg Department of Industrial Chemistry Oldenburg 26111 Carl von Ossietzky Str. 9-11 [email protected] Mr. Deublein, Stephan University of Kaiserslautern Laboratory of Engineering Thermodynamics Kaiserslautern 67653 [email protected] Prof. Dohrn, Ralf Bayer Technology Services GmbH Kinetics, Properties & Modelling Leverkusen 51368 Gebäude B310 [email protected] Mr. Dorn, Udo TU Berlin, TK Chair of Thermodynamics Berlin 10623 Straße des 17.Juni 135 [email protected] Dr. Efimova, Anastasia University of Technology Dresden Department of Inorganic Chemistry Dresden 1069 Bergstraße 66 [email protected]

Prof. Enders, Sabine TU Berlin Chair of Thermodynamics Berlin 10623 Straße des 17.Juni 135, TK7 [email protected] Prof. Gmehling, Jürgen University of Oldenburg Institute of Pure and Applied Chemistry Oldenburg D-26111 Carl von Ossietzky Straße 9-11 [email protected] Mr. Heintz, Andreas University of Rostock Department of Physical Chemistry Rostock D-18051 Hermannstraße 14 [email protected] Mr. Hempel, Sascha Laboratory of Thermodynamics Bio- and Chemical Engineering Dortmund 44227 Emil-Figge-Str. 70 [email protected] Dr. Ignatiev, Nikolai Merck KGaA, PM-ABE Darmstadt 64293 Frankfurter Straße 250 [email protected] Dr. Kalies, Grit University of Leipzig Institute of Experimental Physics I Leipzig 4103 Linnestraße 5 [email protected] Ms. Mehling, Tanja TU Hamburg-Harburg Institute of Thermal Separation Processes Hamburg 21073 Eissendorferstr. 38 [email protected]


Ph.D. Merker, Thorsten University of Kaiserslautern Engineering Thermodynamics Laboratory Kaiserslautern 67663 Erwin-Schroedinger-Straße 44 [email protected] Dr. Mokrushina, Liudmila Friedrich-Alexander-University Erlangen-Nuremberg Chair of Separation Science & Technology Erlangen 91058 Egerlandstr. 3 [email protected] Mr. Mueller, Karsten University of Erlangen-Nuremberg Chair of Separation Science & Technology Erlangen 91058 Egerlandstr. 3 [email protected] Mr. Niño-Amezquita, Oscar TU Berlin, TK 7 Chair of Thermodynamics Berlin 10623 Straße des 17.Juni 135 [email protected] Prof. Sadowski, Gabriele TU Dortmund Biochemical and Chemical Engineering Dortmund 44227 Emil-Figge-Str. 70 Raum G2-519a [email protected] Dr. Sass, Richard DECHEMA E.V. Information Systems and Databases Frankfurt 60486 Theodor-Heuss-Allee 25 [email protected]

Mr. Schrader, Philipp TU Berlin, TK Chair of Thermodynamics Berlin 10623 Straße des 17.Juni 135 [email protected] Prof. Smirnova, Irina Hamburg University of Technology Department of Chemical Engineering Hambrug 21073 Eissendorferstr. 38 [email protected] Mrs. Sponsel, Elke University of Erlangen-Nuremberg Chair of Separation Science and Technology Erlangen 91058 Egerlandstraße 3 [email protected] Prof. Verevkin, Sergey University of Rostock Chemical Department Rostock 18059 Dr-Lorenz-Weg-1 [email protected] Mr. Völkl, Johannes University of Erlangen-Nuernberg Chair of Separation Science and Technology Erlangen 91058 Egerlandstraße 3 [email protected] Ms. Wille, Susanne University of Erlangen-Nuernberg Chair of Separation Science and Technology Erlangen 91058 Egerlandstraße 3 [email protected]


Greece Ph.D. Alevizou, Efthymia National Technical University of Athens Department of Chemical Engineering Athens GR 15780 9 Heroon Polytechniou [email protected] Dr. Louli, Vasiliki National Technical University of Athens Department of Chemical Engineering Athens GR 15780 9 Heroon Polytechniou [email protected] Prof. Magoulas, Konstantinos National Technical University of Athens Department of Chemical Engineering Athens GR 15780 9 Heroon Polytechniou [email protected] Prof. Stamataki, Sofia National Technical University of Athens Department of Mining and Metallurgical Engineering Athens GR 15780 9 Heroon Polytechniou [email protected] Prof. Voutsas, Epameinondas National Technical University of Athens Department of Chemical Engineering Athens GR 15780 9 Heroon Polytechniou [email protected]

India Dr. Singh, Jayant Indian Institute of Technology Kanpur Department of Chemical Engineering Kanpur 208016 IIT [email protected] Iran Prof. Akhavan-Behabadi, Mohammad Ali University of Tehran School of Mechanical Engineering Tehran 1439957131 P.O.Box: 11155-4563 [email protected] Dr. Dehghani Sanij, Mohammad Reza Iran University of Science and Technology School of Chemical Engineering Tehran 1684613114 Narmak [email protected] Prof. Majlesi, Kavosh Chemistry Department, Islamic Azad University, Science and Research Branch TEHRAN 1477893855 Hesarak [email protected] Mrs. Nikbakht, Fatemeh Persian Gulf University Department of Chemical Engineering Shiraz 7177877867 No. 235 , Safir St., Amirkabir Av. [email protected]


Israel Dr. Polishuk, Ilya Ariel University Center of Samaria Department of Chemical Engineering & Biotechnology Ariel 40700 [email protected] Italy Dr. De Angelis, Maria Grazia Università di Bologna DICMA Bologna 40131 Via Terracini 28 [email protected] Mr. Di Nicola, Giovanni Università Politecnica delle Marche Energetica Ancona 60100 Via Brecce Bianche [email protected] Prof. Sarti, Giulio University of Bologna Chemical Engineering, Mining and Environmental Technology (DICMA) Bologna 40131 via Terracini 28 [email protected] Japan Prof. Kato, Satoru Tokyo Metropolitan University Department of Applied Chemistry Hachiohji 1920397 Mihamiohsawa [email protected] Mr. Okubo, Nobuaki SII NanoTechnology Inc. Analytical Application Engineering Dept. Tokyo 104-0041, 2-15-5, Shintomi, Chuo-ku [email protected]

Prof. Saito, Kazuya University of Tsukuba Department of Chemistry Tsukuba 305-8571 1-1-1 Tennodai [email protected] Prof. Takada, Akira Asahi Glass Company, Research Center Yokohama 221-8755 1150 Hazawa-cho Kanagawa-ku [email protected] Mexico Prof. Bonilla-Petriciolet, Adrian Instituto Tecnológico de Aguascalientes Chemical Engineering Department Aguascalientes 20256 Av. López Mateos 1801 [email protected] Netherlands Prof. De Loos, Theodoor Willem Delft University of Technology Department of Process and Energy Delft 2628 CA Leeghwaterstraat 44 [email protected] Mr. Hendriks, Eric Shell Global Solutions GSNL-PTI/RF Amsterdam 1031 HW Grasweg 31 [email protected] Dr. Mattea, Facundo Delft University of Technology Department of Process and Energy Delft 2628 CA Leeghwaterstraat 44 [email protected]


Mr. Nanninga, Gert Purac Competence Centre Process Technology Gorinchem 4206AC Arkelsedijk 46 [email protected] Dr. Van Bochove, Gerard Purac Competence Centre Process Technology Gorinchem 4206AC Arkelsedijk 46 [email protected] Prof. Vlugt, Thijs Delft University of Technology Process & Energy Department Delft 2628CA Leeghwaterstraat 44 [email protected] Norway Dr. Skouras, Efstathios Statoil Gas Processing and LNG Trondheim 7018 Arkitekt Ebbels veg 10, Rotvoll [email protected] Poland Prof. Borówko, Małgorzata Ewa Maria Curie-Skłodowska University Department for the Modelling of Physico-Chemical Processes Lublin, 20-031 Maria Curie-Skłodowska Sq. 3 [email protected]

Prof. Chorążewski, Miroslaw University of Silesia Department of Physical Chemistry Katowice, 40-006 Szkolna 9 [email protected] Prof. Domańska-Żelazna, Urszula Maria Warsaw University of Technology Faculty of Chemistry Warsaw, 00-664 ul. Noakowskiego 3 [email protected] Dr. Drach, Mateusz Maria Curie-Skłodowska University Faculty of Chemistry Lublin, 20-031 Maria Curie-Skłodowska Sq. 5 [email protected] Prof. Kosmulski, Marek Lublin University of Technology Department of Electrochemistry Lublin, 20-618 Nadbystrzycka 38 A [email protected] Dr. Łuczyński, Jacek Wroclaw University of Technology Department of Chemistry Wrocław, 50-370 wyb. Stanisława Wyspiańskiego 27 [email protected] Dr. Makowska, Anna University of Warsaw Faculty of Chemistry Warsaw, 02-089 ul. Żwirki i Wigury 101 [email protected]


Ms. Matkowska, Dobrochna Maria Warsaw University of Technology Department of Physical Chemistry Warsaw, 02-626 Al. Niepodległości 46/50 [email protected] Prof. Narkiewicz-Michałek, Jolanta Grażyna Maria Curie-Skłodowska University Faculty of Chemistry Lublin, 20-031 Maria Curie-Skłodowska Sq. 3 [email protected] Prof. Olchowik, Jan Technical University of Lublin Department of Physics Lublin, 20-618 Nadbystrzycka 38 [email protected] Mr. Paduszyński, Kamil Warsaw University of Technology Faculty of Chemistry Warsaw, 00-664 ul. Noakowskiego 3 [email protected] Dr. Poźniak, Ryszard Wroclaw University of Technology Department of Chemistry Wrocław, 50-370 wyb. Stanisława Wyspiańskiego 27 [email protected] Dr. Siporska, Agnieszka University of Warsaw Department of Chemistry Warsaw, 02-089 Żwirki i Wigury 101 [email protected]

Dr. Staszewski, Tomasz Maria Curie-Skłodowska University Department for the Modelling of Physico-Chemical Processes Lublin, 20-031 Maria Curie-Skłodowska Sq. 3 [email protected] Prof. Szymula, Marta Teresa Maria Curie-Skłodowska University Faculty of Chemistry Lublin, 20-031 Maria Curie-Skłodowska Sq. 3 [email protected] Portugal Mr. Carneiro, Aristides University of Porto Department of Chemical Engineering Porto, 4200-465 Rua Dr. Roberto Frias [email protected] Ms. Cristino, Ana Filipa Russo de Albuquerque University of Lisbon, Faculty of Sciences Department of Chemistry and Biochemistry Lisbon, 1749-016 Campo Grande Ed C8 [email protected] Prof. Filipe, Eduardo Jorge Morilla Instituto Superior Técnico Department of Chemical Enginering Lisbon, 1049-001 Av. Rovisco Pais [email protected]


Mr. Garrido, Nuno Miguel University of Porto, School of Engineering Laboratory of Separation and Reaction Engineering Porto, 4200-465 Rua Dr. Roberto Frias [email protected] Prof. Lampreia, Isabel University of Lisbon Department of Chemistry and Biochemistry Lisbon, 1749-017 Campo Grande [email protected] Prof. Lourenço, Maria Jose Vitoriano University of Lisbon, Faculty of Sciences Lisbon, 1749-016 Campo Grande Ed C8 [email protected] Prof. Macedo, Maria Eugénia Rebello de Almeida University of Porto Faculty of Engineering, Department of Chemical Engineering Porto, 4200-465 Rua Dr. Roberto Frias [email protected] Dr. Mota, Fátima University of Porto Laboratory of Separation and Reaction Engineering Porto, 4200-465 Rua Dr. Roberto Frias [email protected] Prof. Nieto De Castro, Carlos Alberto University of Lisbon, Faculty of Sciences Department of Chemistry and Biochemistry Lisbon, 1749-016 Campo Grande Ed C8 [email protected]

Dr. Oliveira, Mariana Belo University of Porto, Laboratory of Separation and Reaction Engineering Porto, 4200-465 Rua Dr. Roberto Frias [email protected] Mr. Padrela, Luis Miguel Instituto Superior Técnico Department of Chemical and Biological Engineering Lisbon, 1049-001 Av. Rovisco Pais [email protected] Dr. Pinho, Simão Pedro Laboratory of Separation and Reaction Engineering (LSRE) Departamento de Tecnologia Química e Biológica Instituto Politécnico de Bragança Campus de Santa Apolónia Apartado 1134, 530-857 Bragança, Portugal [email protected] Mr. Pires, José Carlos Magalhães University of Porto, Faculty of Engineering Porto, 4200-465 Rua Dr. Roberto Frias [email protected] Dr. Queimada, António José University of Porto Laboratory of Separation and Reaction Engineering Porto, 4200-465 Rua Dr. Roberto Frias [email protected] Ms. Queirós, Carla Gonçalves University of Lisbon, Faculty of Sciences Centre for Molecular Sciences and Materials Lisbon, 1749-016 Campo Grande Ed C8 [email protected]


Ms. Ribeiro, Ana Paula da Costa University of Lisbon, Faculty of Sciences Department of Chemistry and Biochemistry Lisbon, 1749-016 Campo Grande Ed C8 [email protected] Dr. Santos, Ângela Filomena Simões University of Lisbon, Faculty of Sciences Department of Chemistry and Biochemistry Center of Molecular Sciences and Materials Lisbon, 1749-016 Campo Grande Ed C8 [email protected] Ms. Silvério, Sara Cruz University of Porto, Faculty of Engineering Porto, 4200-465 Rua Dr. Roberto Frias [email protected] Ms. Vieira, Salomé Cardoso University of Lisbon, Faculty of Sciences Department of Chemistry and Biochemistry Lisbon, 1749-016 Campo Grande Ed C8 [email protected] Russia Dr. Balaban, Anton St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Dr. Balankina, Elena Moscow State University for Instrumental Engineering and Information Technology Moscow, 107846 ul. Stromynka, 20 [email protected]

Mrs. Bogatishcheva, Natalia Institute of Thermal Physics Ekaterinburg, 620016 Amundsena St., 106 [email protected] Prof. Brodskaya, Elena St.Petersburg State University Department of Chemistry, Chair of Colloid Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Dr. Burov, Stanislav St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Dr. Chernik, Galina St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Mr. Chislov, Mikhail St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Ms. Efimova, Irina Kazan (Volga region) Federal University Department of Physical Chemistry Kazan, 420008 Kremlevskaya St., 18 [email protected]


Dr. Fillippova, Tatiana Institute of Macromolecular Compounds of RAS 199004 Bolshoy prosp. V.O. 31, St. Petersburg [email protected] Prof. Gavrichev, Konstantin Kurnakov Institute of General and Inorganic Chemistry RAS Laboratory of Thermal Analysis and Calorimetry Moscow, 119991 Leninsky prospect, 31 [email protected] Dr. Gotlib, Igor St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Ms. Idrisova, Svetlana Bashkir State University Department of Applied Physics 450074 Validy str. 32, Ufa [email protected] Ms. Koneva, Alina St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Mrs. Konstantinova, Natalia Moscow State University Department of Chemistry Laboratory of Chemical Thermodynamics [email protected]

Ms. Koroleva, Sofia St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Dr. Kostko, Andrei St. Petersburg State University of Refrigeration and Food Engineering Department of Physics St.Petersburg, 191002 Lomonosov Str., 9 [email protected] Dr. Kuranov, George St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Dr. Lobacheva, Olga Saint-Petersburg State Mining Institute Faculty of General and Physical Chemistry 199106 Saint-Petersburg, V.O., 21 Line, 2 [email protected] Ms. Mikhailovskaya, Alesya St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Prof. Mikhelson, Konstantin St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected]


Dr. Missyul, Alexander St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Prof. Morachevsky, Alexey St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Dr. Mudzhikova, Galina St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg FAX +7 812 4286939 [email protected] Acad. Panarin, Eugeny Institute of Macromolecular Compounds of RAS 199004 Bolshoy prosp. V.O. 31, St. Petersburg [email protected] Ms. Penkova, Anastasia St.Petersburg State University Department of Chemistry, Chair of Chemical Thermodynamics and Kinetics 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Dr. Prikhodko, Igor St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected]

Mr. Pronkin, Dmitry Netzsch Gerätebau GmbH Moscow, 119313 Leninskiy prosp., 95 A [email protected] Ms. Pulyalina, Alexandra St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Mr. Rumyantsev, Alexander Analytical Equipment Moscow, 123557 B. Tishinskii per., 38, of. 730 [email protected] Acad. Rusanov, Anatoly St.Petersburg State University Department of Chemistry, Chair of Colloid Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Dr. Safonova, Evgenia St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Mrs. Sankovich, Anna St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected]


Ms. Shapovalova, Anastasiya St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Prof. Shchekin, Alexander St.Petersburg State University Department of Physics, Chair of Statistical Physics 198504 Ulyanovskaya 1, Petrodvoretz, St. Petersburg [email protected] Mr. Silyukov, Oleg St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Dr. Sizov, Vladimir St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Prof. Smirnova, Natalia St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Prof. Sokolova, Ekaterina St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected]

Acad. Stolyarova, Valentina St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Prof. Syunyaev, Rustem Gubkin Russian State University of Oil and Gas, Department of Physics Moscow, 119991 Leninsky prosp., 65 [email protected] Dr. Tatyanenko, Dmitry St. Petersburg State University Division of Theoretical Physics, V.A. Fock Research Institute of Physics, Faculty of Physics, 198504 Ulyanovskaya 1, Petrodvoretz, St. Petersburg [email protected] Prof. Toikka, Alexander St.Petersburg State University Department of Chemistry, Chair of Chemical Thermodynamics and Kinetics 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Ms. Toikka, Maria St.Petersburg State University Department of Chemistry, Chair of Chemical Thermodynamics and Kinetics 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Acad. Tretiakov, Yury Moscow State University Department of Chemistry 119991, Leninskie Gory 1 building 3, Moscow [email protected]


Ms. Trofimova, Maya St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Mr. Tsvetov, Nikita St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Mr. Tsyrulnikov, Sergey St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Ms. Venediktova, Anastasya St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Mrs. Vetrova, Tatiana Netzsch Gerätebau GmbH Moscow, 119313 Leninskiy prosp., 95 A [email protected] Prof. Victorov, Alexey St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected]

Ms. Yakovleva, Marina St.Petersburg State University Department of Chemistry 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] Prof. Zvereva, Irina St.Petersburg State University Department of Chemistry, Chair of Chemical Thermodynamics and Kinetics 198504 Universitetsky prosp. 26, Petrodvoretz, St. Petersburg [email protected] South Africa Mr. De Villiers, Adriaan Jacobus University of Stellenbosch Department of Process Engineering Private Bag X1, Matieland 7602 [email protected] Dr. Reddy, Prashant University of KwaZulu-Natal Department of Chemical Engineering Durban, 4041 King George V Avenue [email protected] South Korea Prof. Park, Yoonkook Hongik University Department of Biological and Chemical Engineering 339-701, 300 Shinan-ri Jochiwon-up Yongi-gun Chungnam [email protected]


Spain Prof. Arce, Alberto University of Santiago de Compostela Department of Chemical Engineering Rúa Lope Gómez de Marzoa s/n, Campus Vida 15782 Santiago de Compostela [email protected] Prof. Chamorro Camazón, César Rubén Universidad de Valladolid Valladolid, 47011 Paseo del Cauce, 59 [email protected] Prof. Fernández, Josefa University of Santiago de Compostela Department of Applied Physics 15782 Campus Vida [email protected] Dr. Francisco Casal, María University of Santiago de Compostela Department of Chemical Engineering Rúa Lope Gómez de Marzoa s/n, Campus Vida 15782 Santiago de Compostela [email protected] Dr. Gordillo Romero, María Dolores University of Cádiz Department of Chemical Engineering and Food Technology 11510 Campus Puerto Real, Cádiz [email protected] Dr. Llovell, Felix Institut de Ciència de Materials de Barcelona (ICMAB) Campus de la Universitat Autònoma de Barcelona 08193 Bellaterra, Barcelona [email protected]

Prof. Marcos, Rosa Universitat Rovira i Virgili Department of Mechanical Engineering Tarragona, 43007 ETSE, Avinguda dels Països Catalans 26 [email protected] Prof. Martín, María del Carmen University of Valladolid Department of Energy Systems Valladolid, 47011 Paseo del Cauce, 59 [email protected] Dr. Montero, Eduardo Universidad de Burgos Department of Electromechanical Engineering Burgos, 9006 Avenida Cantabria s/n [email protected] Prof. Pando García-Pumarino, Concepción Universidad Complutense de Madrid Dpto Química Física I. Facultad CC. Químicas Ciudad Universitaria 28040 MADRID [email protected] Mrs. Pereyra López, Clara María University of Cádiz Department of Chemical Engineering and Food Technology 11510 Campus Puerto Real, Cádiz [email protected] Prof. Renuncio, Juan Antonio Rodríguez Universidad Complutense de Madrid Dpto Química Física I. Facultad CC. Químicas Ciudad Universitaria 28040 MADRID [email protected]


Dr. Rodríguez, Hector University of Santiago de Compostela Department of Chemical Engineering Rúa Lope Gómez de Marzoa s/n, Campus Vida 15782 Santiago de Compostela [email protected] Prof. Rodríguez Romero, Juan Francisco University of Castilla la Mancha Department of Chemical Engineering Ciudad Real, 13071, Avda. Camilo José Cela, s/n [email protected] Prof. Segovia Puras, José Juan University of Valladolid Department of Energy Systems Valladolid, 47011 Paseo del Cauce, 59 [email protected] Prof. Soto, Ana University of Santiago de Compostela Department of Chemical Engineering Rúa Lope Gómez de Marzoa s/n, Campus Vida 15782 Santiago de Compostela [email protected] Prof. Vega, Lourdes Matgas Research Center Department Campus UAB 08193 Bellaterra, Barcelona [email protected] Ph.D. Vila, Juan Universidade da Coruña Department of Physics Coruña, 15008 Campus da Zapateira [email protected]

Prof. Villamañán, Miguel Universidad de Valladolid School of Engineering Valladolid, 47011 Paseo del Cauce, 59 [email protected] Sweden Dr. Kocherbitov, Vitaly Malmö University Faculty of Health and Society S-205 06, Malmö [email protected] Switzerland Mr. Grützner, Thomas Lonza AG, Chemical Department Visp, 3930 [email protected] Mr. Riegler, Jürgen Lonza AG, Chemical Department Visp, 3930 [email protected] Mr. Ott, Lothar Lonza AG, Chemical Department Visp, 3930 [email protected] Tunisia Ms. Jaouahdou, Aroussia National School of Engineering Tunisia Department of Mechanics&Energetics Tunis, 1005 4 bis Rue Jules Verne el Omrane [email protected]


United Kingdom Prof. Sazhin, Sergei University of Brighton School of Computing, Engineering and Mathematics Brighton, BN2 4GJ Lewes Road [email protected] Prof. Trusler, John Paul Martin Imperial College London Department of Chemical Engineering London, SW7 2AZ South Kensington Campus [email protected] Dr. Horsch, Martin Imperial College London Department of Chemical Engineering London, SW7 2AZ South Kensington Campus [email protected] Dr. Secuianu, Catinca Imperial College London / Politehnica University of Bucharest London, SW7 2AZ South Kensington Campus [email protected] Dr. Galindo, Amparo Cenrte for Process Systems Engineering Department of Chemical Engineering London, SW7 2AZ [email protected]

United Arab Emirates Prof. Peters, Cornelis Johan Petroleum Institute Department of Chemical Engineering Abu Dhabi, 2533 Bu Hasa Building, Room 2207 A.P.O.Box 2533 [email protected] United States of America Prof. Anisimov, Mikhail University of Maryland Department of Chemical and Biomolecular Engineering College Park, MD 20742 [email protected] Mr. Muzny, Chris N.I.S.T. Thermodynamics Research Center, 80305 Boulder 325 Broadway St. [email protected] Prof. O’Connell, John University of Virginia Department of Chemical Engineering Charlottesville, VA 102 Engineers Way, P.O. Box 400741 [email protected] Ms. Subramanian, Deepa University of Maryland Department of Chemical and Biomolecular Engineering College Park, MD 20742 [email protected]


Dr. Gor, Gennady Rutgers University Department of Chemical and Biochemical Engineering Piscataway, NJ 8854, 98 Brett rd [email protected] Prof. Elliott, Jarrell Richard Jr. University of Akron Department of Chemical and Biomolecular Engineering Akron, 44325-3906 [email protected]

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