research article application of cosmo-rs method for the...

Research ArticleApplication of COSMO-RS Method for the Prediction ofLiquid-Liquid Equilibrium of Watern-Dodecane1-Butanol

S Balasubramonian Shekhar Kumar D Sivakumar and U Kamachi Mudali

Reprocessing RampD Division Reprocessing Group Indira Gandhi Centre for Atomic Research Kalpakkam 603102 India

Correspondence should be addressed to Shekhar Kumar shekharigcargovin

Received 2 December 2013 Accepted 19 December 2013 Published 5 February 2014

Academic Editors G L Aranovich and F Martınez

Copyright copy 2014 S Balasubramonian et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

The liquid-liquid equilibrium (LLE) for the system water-dodecane-butanol was estimated using the UNIQUAC model In theUNIQUACmodel interaction parameterswere estimated from the vapor-liquid equilibrium (VLE) andLLEdata of their constituentbinary pairsThewater-dodecane-butanol LLEwas experimentally measured at 29815 K Phase stability constraints were taken intoaccount while calculating the binary interaction parameters from the mutual solubility data The COSMO-RS method was usedto estimate the activity coefficient in the miscible binary pair The ternary LLE composition was predicted using the experimentalVLE data as well as using the COSMO-RS calculated activity coefficient data along with the experimental mutual solubility data Inthe latter case the root mean square deviation (RMSD) for the distribution of butanol between aqueous and organic phase is 024The corresponding UNIFAC model prediction is 763

1 Introduction

Extraction of uranium and plutonium from the spent nuclearfuel using PUREXmethod employs tributyl phosphate (TBP)as the extractant and dodecane as the diluent During solventextraction TBP and dodecane undergo hydrolytic and radi-olytic degradation and form dibutyl phosphate monobutylphosphate butanol and several other organic compounds [1]In order to understand the distribution of these compoundsin the PUREX process stream their liquid-liquid equilibrium(LLE) behavior between the aqueous and organic phase mustbe known The accurate prediction of LLE using the limitedamount of experimental data was investigated by severalresearchers [2ndash6] Anderson and Prausnitz [2] described theapplication of UNIQUAC model for the prediction of LLEThe type II ternary systems which have two partially misciblebinaries can be predicted using the binary parameter quiteaccurately Magnussen et al [3] reported separate param-eter table for the prediction of LLE using UNIFAC groupcontribution model Recently COSMO-RS model reportedby Klamt and Eckert [6 7] for the prediction of fluid phasethermodynamic properties is gaining importance to predictLLE Several authors used COSMO-RS method to predict

LLE of system containing water hydrocarbon alcohols andionic liquids [8ndash10]

The various excess Gibbs energy model such as NRTLUNIQUAC and UNIFAC can be used to predict the mul-ticomponent LLE These models contain the interactionparameters which are usually estimated from the binaryexperimental data The miscible binary pair interactionparameters were estimated from VLE data Similarly forpartially miscible pair mutual solubility data were used toestimate the interaction parameter Islam et al [11] proposeduniversal set of parameters for predicting both VLE andLLE The hexane-butanol-water ternary LLE was predictedusing this universal set of parametersTheUNIQUAC surfacearea parameter was expressed as the linear function ofconcentration to improve the prediction of ternary LLE [12]According to Anderson and Prausnitz [2] reasonable binaryVLE data is sufficient to predict the type II ternary LLEusing UNIQUAC model In this work miscible pair activitycoefficient data estimated using COSMO-RS method wasused to predict the ternary LLE along with the experimentalmutual solubility data Thus by reducing the experimentaldata required in the prediction of LLE The COSMO-RSgenerated activity coefficient data was used to estimate

Hindawi Publishing CorporationISRN ermodynamicsVolume 2014 Article ID 415732 6 pageshttpdxdoiorg1011552014415732

2 ISRNThermodynamics

Table 1 The pure component density and refractive index measured at 29815 K

Density at 25∘C gcm3 Refractive index (119899119863

) UNIQUAC structural parameterComponent This work Literature This work Literature 119903 119902

Dodecane 0745318 074523a 1419489 14196a 85462 7096Butanol 0806452 080558b 1397134b 13972 34543 3052Water 0997046 0997048b 1332421b 13325 092 14aReference [35]bReference [36]

theUNIQUAC interaction parameter for completelymisciblepair

The water-dodecane-butanol ternary LLE system waspredicted using available binary experimental data (caseA) and the COSMO-RS estimated activity coefficient datainstead of experimental VLE data (case B) In both casesavailable experimental mutual solubility data were used toestimate the UNIQUAC interaction parameter for partiallymiscible pair Special attention was paid to estimate theUNIQUAC interaction parameter from the mutual solubilitydata UNIQUAC interaction parameters were estimated fromthe mutual solubility data based on the method proposed byMitsos et al [13] In their work the phase stability constraintwas satisfied alongwith the equality of activity in both phasesThe UNIFAC group contribution method was also used toestimate the ternary LLE The UNIFAC LLE parameter tablegiven byMagnussen et al [3] was usedThe experimental andpredicted results using UNIQUAC (case A and case B) andUNIFAC were compared

2 Experimental Methods

Butanol and dodecane with a purity of 99 supplied byLoba Chemie and Sigma Aldrich respectively were usedas received The pure component density (120588) and refractiveindex (nD) were measured at 29815 K and given in Table 1ASTM Grade-I water as per ASTM D-1193-99 (1999) witha resistivity of 182MΩsdotcm at 29815 K and TOC lt 15 ppbfrom a MILLIPORE Simplicity system was used in theexperiments

The known amounts of dodecane butanol and waterwere weighed in the precision SHIMADZU AUW 220 dbalance (220 g82 g 01001mg resolution) and taken into100mL flask and stirred bymagnetic stirrer for 3 hrs and thenallowed to settle for 12 hrs After settling the samples werecollected fromboth phases and centrifugedThe butanol con-centrations present in the aqueous and organic samples wereanalyzed by refractometry and gas chromatography (GC)respectively The density and refractive index were measuredwith Anton Paar DMA-5000 densitometer coupled withRXA-156 refractometer The organic water concentrationwas determined by densimetry The organic phase densitywas expressed as a function of water composition The lowconcentration of butanol in the organic phase was analyzedby gas chromatography In the cases of larger concentrationof butanol gravimetric method was employed

Table 2 UNIQUAC interaction parameter (119886119894119895

) calculated usingexperimental VLE data and COSMO-RS activity coefficient data

Experimental (Case A) COSMO-RS (Case B)Component 119886

119894119895

c119886119895119894

119886119894119895

119886119895119894

Butanol-dodecaneminus10505 35218 minus14586 535426c120591119894119895= exp(minus119886

119894119895119879)

Table 3 UNIQUAC interaction parameter estimated from mutualsolubility data and their RMSD () in their estimation

Binary pair (119894-119895) 119886119894119895

119886119895119894

RMSD ()Butanol-water minus5896 26597 0469Dodecane-water 1300 342 175

3 Calculation Method

The UNIQUAC model was used to express the liquid phaseactivity coefficient The group contribution model UNIFACwas used to find the ternary LLE composition and comparedwith the UNIQUAC prediction The details of these modelscan be found in Abrams and Prausnitz [14] and Fredenslundet al [15] The UNIQUAC binary interaction parameterswere estimated from the VLE and mutual solubility data ofthe constituent binary pairs The experimental data selectionand parameter estimation from the experimental mutualsolubility data are discussed in Sections 31 and 32 Themodified Rachford Rice algorithm [16] was used to estimatethe ternary LLE phase compositions The initial estimate ofthe phase compositions was provided as mole fraction andthe corresponding equilibrium compositions were estimatedThe liquid phase activity coefficient was estimated from theUNIQUAC and UNIFAC model All the calculations weredone at 29815 K

31 Data Selection A thorough literature survey was carriedout to collect the VLE data of butanol-dodecane pair andmutual solubility data of dodecane-water and butanol-waterFrom the selected experimental data UNIQUAC binaryinteraction parameters were estimatedThe selected final dataand the estimated UNIQUAC binary interaction parametersare given in Tables 2 and 3 The experimental and estimatedmutual solubility data using UNIFAC and UNIQUAC areshown in Table 4

311 Butanol-Dodecane For butanol-dodecane isothermalVLE data and UNIQUAC interaction parameter (120591

119894119895)

ISRNThermodynamics 3

Table 4 The experimental and calculated mutual solubility using UNIQUAC and UNIFAC

Binary pair (119894-119895)

Solubility119894 in 119895 119895 in 119894

Exp Calc Exp CalcUNIQUAC (cases A and B) UNIFAC UNIQUAC (cases A and B) UNIFAC

Dodecane-water 4 times 10minus10 361 times 10minus8

356 times 10minus8

61 times 10minus4

119 times 10minus3

119 times 10minus3

Butanol-water 001896 001873 003169 051183 05052 05310

reported by Belabbaci et al [17] is available only at 31315 KThis UNIQUAC parameter (120591

119894119895) was used to calculate

the binary interaction parameter (119886119894119895) at 29815 K using

the relation 120591119894119895= exp(119886

119894119895119877119879) The activity coefficient is

estimated from the experimental data by using the followingequation and the correction for vapor phase nonideality isnot taken into account

120574119894=

119875 sdot 119910119894

119875119900

119894

sdot 119909119894

(1)

312 Dodecane-Water Thedodecane-water pair has very lowsolubility of dodecane in water and vice versa Shaw et al [18]have compiled the solubility data of dodecane in water andwater in dodecane Franks [19] and Sutton and Calder [20]reported dodecane solubility in water at 2982 KThe value of4 times 10

minus10 for dodecane solubility in water and a value of 61 times10minus4 for water solubility in dodecane reported by Sutton and

Calder [20] and Schatzberg [21] respectively were chosen

313 Butanol-Water 1-Butanol-water is partially miscibleThe mutual solubility of butanol-water has been reported inliterature [22ndash32] The average value of 001896 was chosenamong the literature reported solubility data [22ndash29] for thebutanol solubility in water The water solubility in butanol at29815 K was chosen as 051183 which is the average value ofthe literature reported data [22ndash24 26 30ndash32]

32 Parameter Estimation The UNIQUAC interactionparameter for the miscible pair in the ternary liquid-liquid system was estimated using the literature reportedexperimental vapor liquid equilibrium data (case A) andalso using the COMSO-RS generated activity coefficient data(case B) In case B the activity coefficient data estimatedusing the COSMO-RSmodel implemented in COSMOtherm[33] software is used to estimate the UNIQUAC interactionparameter In COSMO-RS estimation of activity coefficientTZVP basis set cosmo database was used for all thecomponents

Estimation of binary interaction parameter for excessGibbs free energy model such as UNIQUAC is a challengingtask due to the nonlinear nature of the equation The nonlin-ear equation to be solved for the binary parameter may haveunknown number of solutions or no solution at all [13 34]In order to predict the ternary liquid-liquid equilibrium weneed to determine the unique binary parameter for the givenbinary So themethod proposed byMitsos et al [13] was usedto estimate the binaryUNIQUAC interaction parameter from

35

3

25

2

15

1

05

00 02 04 06 08 1

Mole fraction of butanol

COSMO-RSUNIFAC

ln(a

ctiv

ity co

effici

ent)

Exp (butanol)Exp (dodecane)

Figure 1 The comparison of experimental and model predictedactivity coefficient of butanol and dodecane

the mutual solubility data In this method additional phasestability condition was satisfied along with the equality ofactivity condition

4 Results and Discussion

Experimental and predicted activity coefficient of butanol-dodecane using COSMO-RS and UNIFACmodel was shownin Figure 1 The UNIQUAC interaction parameter calculatedusing mutual solubility data is given in Table 3 The Gibbstangent plane diagram using UNIQUAC model for the sys-tems dodecane-water and butanol-water is shown in Figures 2and 3 respectivelyThemeasured density and refractive indexfor the aqueous and organic phase are listed in Table 5 Theexperimentally determined composition in the aqueous andorganic phase is shown in Table 6

According to Figure 1 the UNIFAC estimated activitycoefficient for butanol-dodecane is closely matching with theexperimental data In butanol activity coefficient significantdeviation was observed between the COSMO-RS estimatedand experimental data at concentration below 05 molefraction At higher concentrations the COSMO-RS predictedactivity coefficient matches well with the experimental data


Table 5 Measured density and refractive index of water-dodecane-butanol ternary system

Aqueous phase Organic phaseMole fraction Density at 25∘C gcm3 Refractive index Mole fraction Density at 25∘C gcm3 Refractive index

Water Butanol Water Butanol09913 00087 09923 07455 00258 00179 07455 1419209967 00033 09953 07453 0035 00024 07453 1419409913 00087 09923 07455 00273 00149 07455 141920982 0018 09874 07716 02254 04435 07716 1408509826 00174 09876 07653 0167 04116 07653 1410709829 00171 09878 07623 01419 03826 07623 1411809899 00101 09914 07456 00248 00221 07456 1419109831 00169 09879 07799 02858 04744 07799 1405809829 00171 09878 07672 01849 04228 07672 14101

Table 6 Experimental ternary data for water-dodecane-butanol (in mole fraction)

Overall mole fraction Aqueous phase Organic phaseWater Butanol Dodecane Water Butanol Dodecane Water Butanol Dodecane05986 00125 03889 09913 00087 00000 00258 00179 0956305008 00029 04963 09967 00033 00000 00350 00024 0962605031 00119 04850 09913 00087 00000 00273 00149 0957905991 02340 01669 09820 00180 00000 02254 04435 0331105850 02101 02049 09826 00174 00000 01670 04116 0421506574 01589 01837 09829 00171 00000 01419 03826 0475505073 00162 04765 09899 00101 00000 00248 00221 0953006244 02530 01227 09831 00169 00000 02858 04744 0239806688 01772 01539 09829 00171 00000 01849 04228 03923

In the estimation of dodecane activity coefficient COSMO-RS values were closer to the experimental data at infinitedilution and higher concentration region in other placesthe estimated values were higher than the experimentaldata As UNIFAC group contributions were estimated fromexperimental data it resulted in a better prediction of theactivity coefficient as compared with a-priory prediction byCOSMO-RS

Figure 2 shows that the Gibbs energy ofmixing is positivefor dodecane-water system for the entire concentration rangedue to its very low mutual solubility limits Butanol-water ispartially miscible the solubility of water in the organic phaseis higher as compared to the aqueous solubility So the Gibbsenergy of mixing plot shows highly negative region in thebutanol rich region as shown in Figure 3 The butanol-watershows maximummiscibility gap of mole fraction of 05

The comparison of model predicted and experimentalLLE mole fraction is shown in Figure 4 In Figure 5 theexperimental distribution of butanol in the dilute region isshown along with the model predictions From Figure 4 itis clear that all the models overpredict the water-dodecane-butanol equilibrium composition while UNIQUAC (case Aand case B) predicted values were closer to the experimentalvalues than the UNIFAC estimation The value of distribu-tion coefficient of butanol estimated by various models issignificantly differentThepredicted values of the butanol dis-tribution coefficient were 858 205 and 1280 respectively

0 02 04 06 08 1

0

02

04

06

08

1

Mole fraction of dodecane

Gm

ixR

T

Figure 2 Gibbs tangent plane diagram for the system dodecane-water at 29815 K

for UNIQUAC (case A and case B) and UNIFAC modelThe RMSD () between the experimental and calculatedbutanol distribution in the dilute region is 495 0247 and763 respectively for UNIQUAC (case A and case B) andUNIFAC


0 02 04 06 08 1

0

005


minus005

minus01

minus015

minus02

minus025

minus03

minus035

minus04

Gm

ixR

T

Figure 3 Gibbs tangent plane diagram for the system butanol-waterat 29815 K

00

0

01

01

01

02

02

02

03

03

03

04

04

04

05

0505

06

06

06

07

07

07

08

08

08

09

09

09

1

1

1

Dodecane

Wate

r

Butanol

Figure 4 LLE for the ternary system water-dodecane-butanol at29815 K ◻ experimental data I UNIQUAC (case A) calculated UNIQUAC (case B) calculated 998810 UNIFAC calculated dottedlines are tie lines from experimental data

5 Conclusion

The water-dodecane-butanol liquid-liquid equilibrium com-position is experimentally measured at 29815 KThis ternaryLLE data was predicted from their binary experimentaldata using UNIQUAC model The LLE composition is alsopredicted using the COSMO-RS estimated activity coefficientfor the miscible pair (butanol-dodecane) along with experi-mental mutual solubility data The UNIQUAC prediction isslightly better than the UNIFAC prediction All the modelsoverpredict the heterogeneous region at the butanol rich sideof the ternary system The RMSD () for the predictionof butanol distribution using COSMO-RS calculated activitycoefficient alongwith the experimentalmutual solubility data

0 0005 001 00150

005

01

015

02

Butanol mole fraction in aqueous phase

Buta

nol m

ole f

ract

ion

in o

rgan

ic p

hase

ExpUNIQUAC (case A)

UNIQUAC (case B)UNIFAC

Figure 5 Distribution of butanol between aqueous and organicphase at 29815 K

is 024The accuracy of the ternary LLE prediction dependson the accuracy of binary VLE prediction

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

References

[1] AWright and P PHartmann ldquoReview of physical and chemicalproperties of tributyl phosphatediluentnitric acid systemsrdquoSeparation Science and Technology vol 45 no 12 pp 1753ndash17622010

[2] T F Anderson and J M Prausnitz ldquoApplication of theUNIQUAC equation to calculation of multicomponent phaseequilibria 2 Liquid-liquid equilibriardquo Industrial amp EngineeringChemistry Process Design and Development vol 17 no 4 pp561ndash567 1978

[3] T Magnussen P Rasmussen and A Fredenslund ldquoUNIFACparameter table for prediction of liquid-liquid equilibriardquoIndustrial amp Engineering Chemistry Process Design and Devel-opment vol 20 no 2 pp 331ndash339 1981

[4] I Nagata and K Katoh ldquoEffective UNIQUAC equation in phaseequilibrium calculationrdquo Fluid Phase Equilibria vol 5 no 3-4pp 225ndash244 1981

[5] I Nagata ldquoPrediction of Ternary phase equilibria from binarydatardquoThermochimica Acta vol 56 no 1 pp 43ndash57 1982

[6] A Klamt and F Eckert ldquoCOSMO-RS a novel and efficientmethod for the a priori prediction of thermophysical data ofliquidsrdquo Fluid Phase Equilibria vol 172 no 1 pp 43ndash72 2000

[7] F Eckert and A Klamt ldquoFast solvent screening via quantumchemistry COSMO-RS approachrdquo AIChE Journal vol 48 no2 pp 369ndash385 2002


[8] Y Shimoyama Y Iwai S Takada Y Arai T Tsuji and T HiakildquoPrediction of phase equilibria for mixtures containing waterhydrocarbons and alcohols at high temperatures and pressuresby cubic equation of state with 119866E type mixing rule based onCOSMO-RSrdquo Fluid Phase Equilibria vol 243 no 1-2 pp 183ndash192 2006

[9] T Banerjee R K Sahoo S S Rath R Kumar and AKhanna ldquoMulticomponent liquid-liquid equilibria predictionfor aromatic extraction systems using COSMO-RSrdquo Industrialamp Engineering Chemistry Research vol 46 no 4 pp 1292ndash13042007

[10] M G Freire S P M Ventura L M N B F Santos I MMarrucho and J A P Coutinho ldquoEvaluation of COSMO-RSfor the prediction of LLE and VLE of water and ionic liquidsbinary systemsrdquo Fluid Phase Equilibria vol 268 no 1-2 pp 74ndash84 2008

[11] A W Islam A Javvadi and V N Kabadi ldquoUniversal liquidmixture models for Vapor-Liquid and Liquid-Liquid equilibriain the Hexane-Butanol-Water systemrdquo Industrial amp EngineeringChemistry Research vol 50 no 2 pp 1034ndash1045 2011

[12] Y Iwai and Y Yamamoto ldquoConcentration dependent surfacearea parameter model for calculation of activity coefficientsrdquoFluid Phase Equilibria vol 337 pp 165ndash173 2013

[13] A Mitsos G M Bollas and P I Barton ldquoBilevel optimizationformulation for parameter estimation in liquid-liquid phaseequilibrium problemsrdquo Chemical Engineering Science vol 64no 3 pp 548ndash559 2009

[14] D S Abrams and J M Prausnitz ldquoStatistical thermodynamicsof liquid mixtures a new expression for the excess gibbs energyof partly or completely miscible systemsrdquo AIChE Journal vol21 no 1 pp 116ndash128 1975

[15] A Fredenslund R L Jones and J M Prausnitz ldquoGroup-contribution estimation of activity coefficients in non idealliquid mixturesrdquo AIChE Journal vol 21 no 6 pp 1086ndash10991975

[16] J D Seader and E J Henley Separation Process PrinciplesWiley New York NY USA 1960

[17] A Belabbaci R M Villamanan L Negadi C M Martin A AKaci and M A Villamanan ldquoVapor-liquid equilibria of binarymixtures containing 1-Butanol and hydrocarbons at 31315KrdquoJournal of Chemical and Engineering Data vol 57 no 1 pp 114ndash119 2012

[18] D G Shaw A Maczynski M Goral et al ldquoIUPAC-NIST solu-bility data series 81 Hydrocarbons with water and seawatermdashrevised and updatedmdashpart 10 C

11

and C12

hydrocarbons withwaterrdquo Journal of Physical and Chemical Reference Data vol 35no 1 p 153 2006

[19] F Franks ldquoSolutemdashwater interactions and the solubilitybehaviour of long-chain paraffin hydrocarbonsrdquo Nature vol210 pp 87ndash88 1966

[20] C Sutton and J A Calder ldquoSolubility of higher-molecular-weight normal-paraffins in distilled water and sea waterrdquoEnvironmental Science and Technology vol 8 no 7 pp 654ndash6571974

[21] P Schatzberg ldquoSolubilities of water in several normal alkanesfrom C

7

to C116

rdquo The Journal of Physical Chemistry vol 67 no4 pp 776ndash779 1963

[22] J A V Butler D WThomson andW H Maclennan ldquoThe freeenergy of the normal aliphatic alcohols in aqueous solutionmdashpart I the partial vapour pressures of aqueous solutions ofmethyl n-propyl and n-butyl alcoholsmdashpart II the solubilities

of some normal aliphatic alcohols in watermdashpart III the theoryof binary solutions and its application to aqueous-alcoholicsolutionsrdquo Journal of the Chemical Society pp 674ndash686 1933

[23] R de Santis L Marrelli and P N Muscetta ldquoLiquid-liquidequilibria in water-aliphatic alcohol systems in the presence ofsodium chloriderdquoThe Chemical Engineering Journal vol 11 no3 pp 207ndash214 1976

[24] V Gomis-Yagues F Ruiz-Bevia M Ramos-Nofuentesand andM J Fernandez-Torres ldquoThe influence of the temperature onthe liquid-liquid equilibrium of the ternary system 1-butanolmdash1-propanolmdashwaterrdquo Fluid Phase Equilibria vol 149 no 1-2 pp139ndash145 1998

[25] R S Hansen Y Fu and F E Bartell ldquoMultimolecular adsorp-tion from binary liquid solutionsrdquo The Journal of PhysicalChemistry vol 53 no 6 pp 769ndash785 1949

[26] A E Hill andW M Malisoff ldquoThe mutual solubility of liquidsIII The mutual solubility of phenol and water IV The mutualsolubility of normal butyl alcohol and waterrdquo Journal of theAmerican Chemical Society vol 48 no 4 pp 918ndash927 1926

[27] K Kinoshita H Ishikawa and K Shinoda ldquoSolubility of alco-hols in water determined by the surface tensionmeasurementsrdquoBulletin of the Chemical Society of Japan vol 31 pp 1081ndash10821958

[28] B Marongiu I Ferino R Monaci V Solinas and S TorrazzaldquoThermodynamic properties of aqueous non-electrolyte mix-tures Alkanols+water systemsrdquo Journal of Molecular Liquidsvol 28 no 4 pp 229ndash247 1984

[29] M I Perl A Kisfaludi and P M Szakacs ldquoComposition ofternary systems comprising water n-butyl or isobutyl alcoholand one of the four mineral acids HClO4 HNO3 HCl orH2SO4rdquo Journal of Chemical amp Engineering Data vol 29 no1 pp 66ndash69 1984

[30] F Ruiz M I Galan and N Boluda ldquoQuaternary liquid-liquidequilibrium water-phosphoric acid-1-butanol-2-butanone at25∘Crdquo Fluid Phase Equilibria vol 146 no 1-2 pp 175ndash185 1998

[31] A C G Marigliano M B G de Doz and H N Solimo ldquoInflu-ence of temperature on the liquid-liquid equilibria containingtwo pairs of partiallymiscible liquids water+furfural+1-butanolternary systemrdquo Fluid Phase Equilibria vol 153 no 2 pp 279ndash292 1998

[32] L Lintomen R T P Pinto E Batista A J A Meirelles and MR W Maciel ldquoLiquidminusliquid equilibrium of the water + citricAcid + short chain alcohol + tricaprylin system at 29815 KrdquoJournal of Chemical and Engineering Data vol 46 no 3 pp546ndash550 2001

[33] F Eckert and A Klamt COSMOtherm Version C2 1 Release 0111 COSMOlogic GmbHampCo KG Leverkusen Germany 2010

[34] J P Novak J Matous and J Pick Liquid-Liquid EquilibriaElsevier Amsterdam The Netherlands 1987

[35] C H Su S Y Lin and L J Chen ldquo(Liquid + liquid) equilibriafor the ternary system (water + dodecane + propylene glycol n-propyl ether)rdquo Journal of ChemicalThermodynamics vol 47 pp358ndash361 2012

[36] A M Farhan and A M Awwad ldquoRelative permittivitiesrefractive indices and densities of dihydrofuran-2(3H)-one +butan-1-ol and + butan-2-ol at T = (29315 29815 30315 and31315) Krdquo Journal of Chemical and Engineering Data vol 55no 2 pp 1035ndash1038 2010

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Table 1 The pure component density and refractive index measured at 29815 K

Density at 25∘C gcm3 Refractive index (119899119863

) UNIQUAC structural parameterComponent This work Literature This work Literature 119903 119902

Dodecane 0745318 074523a 1419489 14196a 85462 7096Butanol 0806452 080558b 1397134b 13972 34543 3052Water 0997046 0997048b 1332421b 13325 092 14aReference [35]bReference [36]

theUNIQUAC interaction parameter for completelymisciblepair

The water-dodecane-butanol ternary LLE system waspredicted using available binary experimental data (caseA) and the COSMO-RS estimated activity coefficient datainstead of experimental VLE data (case B) In both casesavailable experimental mutual solubility data were used toestimate the UNIQUAC interaction parameter for partiallymiscible pair Special attention was paid to estimate theUNIQUAC interaction parameter from the mutual solubilitydata UNIQUAC interaction parameters were estimated fromthe mutual solubility data based on the method proposed byMitsos et al [13] In their work the phase stability constraintwas satisfied alongwith the equality of activity in both phasesThe UNIFAC group contribution method was also used toestimate the ternary LLE The UNIFAC LLE parameter tablegiven byMagnussen et al [3] was usedThe experimental andpredicted results using UNIQUAC (case A and case B) andUNIFAC were compared

2 Experimental Methods

Butanol and dodecane with a purity of 99 supplied byLoba Chemie and Sigma Aldrich respectively were usedas received The pure component density (120588) and refractiveindex (nD) were measured at 29815 K and given in Table 1ASTM Grade-I water as per ASTM D-1193-99 (1999) witha resistivity of 182MΩsdotcm at 29815 K and TOC lt 15 ppbfrom a MILLIPORE Simplicity system was used in theexperiments

The known amounts of dodecane butanol and waterwere weighed in the precision SHIMADZU AUW 220 dbalance (220 g82 g 01001mg resolution) and taken into100mL flask and stirred bymagnetic stirrer for 3 hrs and thenallowed to settle for 12 hrs After settling the samples werecollected fromboth phases and centrifugedThe butanol con-centrations present in the aqueous and organic samples wereanalyzed by refractometry and gas chromatography (GC)respectively The density and refractive index were measuredwith Anton Paar DMA-5000 densitometer coupled withRXA-156 refractometer The organic water concentrationwas determined by densimetry The organic phase densitywas expressed as a function of water composition The lowconcentration of butanol in the organic phase was analyzedby gas chromatography In the cases of larger concentrationof butanol gravimetric method was employed

Table 2 UNIQUAC interaction parameter (119886119894119895

) calculated usingexperimental VLE data and COSMO-RS activity coefficient data

Experimental (Case A) COSMO-RS (Case B)Component 119886

119894119895

c119886119895119894

119886119894119895

119886119895119894

Butanol-dodecaneminus10505 35218 minus14586 535426c120591119894119895= exp(minus119886

119894119895119879)

Table 3 UNIQUAC interaction parameter estimated from mutualsolubility data and their RMSD () in their estimation

Binary pair (119894-119895) 119886119894119895

119886119895119894

RMSD ()Butanol-water minus5896 26597 0469Dodecane-water 1300 342 175

3 Calculation Method

The UNIQUAC model was used to express the liquid phaseactivity coefficient The group contribution model UNIFACwas used to find the ternary LLE composition and comparedwith the UNIQUAC prediction The details of these modelscan be found in Abrams and Prausnitz [14] and Fredenslundet al [15] The UNIQUAC binary interaction parameterswere estimated from the VLE and mutual solubility data ofthe constituent binary pairs The experimental data selectionand parameter estimation from the experimental mutualsolubility data are discussed in Sections 31 and 32 Themodified Rachford Rice algorithm [16] was used to estimatethe ternary LLE phase compositions The initial estimate ofthe phase compositions was provided as mole fraction andthe corresponding equilibrium compositions were estimatedThe liquid phase activity coefficient was estimated from theUNIQUAC and UNIFAC model All the calculations weredone at 29815 K

31 Data Selection A thorough literature survey was carriedout to collect the VLE data of butanol-dodecane pair andmutual solubility data of dodecane-water and butanol-waterFrom the selected experimental data UNIQUAC binaryinteraction parameters were estimatedThe selected final dataand the estimated UNIQUAC binary interaction parametersare given in Tables 2 and 3 The experimental and estimatedmutual solubility data using UNIFAC and UNIQUAC areshown in Table 4

311 Butanol-Dodecane For butanol-dodecane isothermalVLE data and UNIQUAC interaction parameter (120591

119894119895)



Binary pair (119894-119895)

Solubility119894 in 119895 119895 in 119894



356 times 10minus8

61 times 10minus4

119 times 10minus3

119 times 10minus3

Butanol-water 001896 001873 003169 051183 05052 05310




the relation 120591119894119895= exp(119886



120574119894=

119875 sdot 119910119894

119875119900

119894

sdot 119909119894

(1)







35

3

25

2

15

1

05

00 02 04 06 08 1


COSMO-RSUNIFAC

ln(a

ctiv

ity co

effici

ent)
















0 02 04 06 08 1

0

02

04

06

08

1


Gm

ixR

T




0 02 04 06 08 1

0

005


minus005

minus01

minus015

minus02

minus025

minus03

minus035

minus04

Gm

ixR

T


00

0

01

01

01

02

02

02

03

03

03

04

04

04

05

0505

06

06

06

07

07

07

08

08

08

09

09

09

1

1

1

Dodecane

Wate

r

Butanol


5 Conclusion


0 0005 001 00150

005

01

015

02


Buta

nol m

ole f

ract

ion

in o

rgan

ic p

hase

ExpUNIQUAC (case A)






References




















11

and C12





7

to C116























FluidsJournal of


Journal of










Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics





Binary pair (119894-119895)

Solubility119894 in 119895 119895 in 119894



356 times 10minus8

61 times 10minus4

119 times 10minus3

119 times 10minus3

Butanol-water 001896 001873 003169 051183 05052 05310




the relation 120591119894119895= exp(119886



120574119894=

119875 sdot 119910119894

119875119900

119894

sdot 119909119894

(1)







35

3

25

2

15

1

05

00 02 04 06 08 1


COSMO-RSUNIFAC

ln(a

ctiv

ity co

effici

ent)
















0 02 04 06 08 1

0

02

04

06

08

1


Gm

ixR

T




0 02 04 06 08 1

0

005


minus005

minus01

minus015

minus02

minus025

minus03

minus035

minus04

Gm

ixR

T


00

0

01

01

01

02

02

02

03

03

03

04

04

04

05

0505

06

06

06

07

07

07

08

08

08

09

09

09

1

1

1

Dodecane

Wate

r

Butanol


5 Conclusion


0 0005 001 00150

005

01

015

02


Buta

nol m

ole f

ract

ion

in o

rgan

ic p

hase

ExpUNIQUAC (case A)






References




















11

and C12





7

to C116























FluidsJournal of


Journal of










Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics












0 02 04 06 08 1

0

02

04

06

08

1


Gm

ixR

T




0 02 04 06 08 1

0

005


minus005

minus01

minus015

minus02

minus025

minus03

minus035

minus04

Gm

ixR

T


00

0

01

01

01

02

02

02

03

03

03

04

04

04

05

0505

06

06

06

07

07

07

08

08

08

09

09

09

1

1

1

Dodecane

Wate

r

Butanol


5 Conclusion


0 0005 001 00150

005

01

015

02


Buta

nol m

ole f

ract

ion

in o

rgan

ic p

hase

ExpUNIQUAC (case A)






References




















11

and C12





7

to C116























FluidsJournal of


Journal of










Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics




0 02 04 06 08 1

0

005


minus005

minus01

minus015

minus02

minus025

minus03

minus035

minus04

Gm

ixR

T


00

0

01

01

01

02

02

02

03

03

03

04

04

04

05

0505

06

06

06

07

07

07

08

08

08

09

09

09

1

1

1

Dodecane

Wate

r

Butanol


5 Conclusion


0 0005 001 00150

005

01

015

02


Buta

nol m

ole f

ract

ion

in o

rgan

ic p

hase

ExpUNIQUAC (case A)






References




















11

and C12





7

to C116























FluidsJournal of


Journal of










Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics















11

and C12





7

to C116























FluidsJournal of


Journal of










Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics








FluidsJournal of


Journal of










Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics



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