organic chemistry with cellulose - step itn
TRANSCRIPT
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Thuringian Institute of Textile and Plastics Research RudolstadtDr. Frank MeisterE-mail: [email protected]
Organic Chemistry with Cellulose
Friedrich Schiller University of JenaCenter of Excellence forPolysaccharide ResearchProf. Dr. Thomas HeinzeE-mail: [email protected]
Basic financial support 2002-2008
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Th. Heinze • Friedrich Schiller University of Jena
-Structure of cellulose-Chemical modification of cellulose:Type of functional group, Number of functional groups(Degree of substitution, DS), and functionalization pattern, Molar mass and molar mass distribution, Purity
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Th. Heinze • Friedrich Schiller University of Jena
Hydrogen bond donator
Hydrogen bond acceptor
(Remember the unusual high boiling point of water)
Most probable hydrogen bond pattern of cellulose I(Kolpak and Blackwell, 1976; 1978)
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Th. Heinze • Friedrich Schiller University of Jena
Crystallite CrystalliteAmorphous
region
Schematic plot of the supramolecular structure of celluloseA. Fringed micelleB. Fringed fibrilCrystallites are marked white and amorphous regions are marked black
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Th. Heinze • Friedrich Schiller University of Jena
Chemical modification of cellulose: The homogeneousversus the heterogeneous reaction path
Homogeneous reaction means to dissolve the biopolymer prior the chemicalreaction either in non-derivatizing- or derivatizing solvents. In case of derivatizing solvents, not only a conversion of the soluble intermediateformed during dissolution but also the modification of the isolated intermediate,which is re-dissolved in an organic solvent (DMSO, DMF) is considered as homogeneous reaction.
Chemical modification of soluble but “stable” cellulose derivativeslike cellulose acetate in DMSO and of cellulose under dissolutionof the cellulose derivative formed, as a result of the conversion,is not included in the context of homogeneous phase chemistry.
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Th. Heinze • Friedrich Schiller University of Jena
CELLULOSE ESTERS
Commercial acylation is exclusively carried out under heterogeneous conditions
OOH
OOH
HO
O
CH3 O CH3
O
OO
OO
O
CH3O
CH3OCH3
O(CH3COOH)Catalyste.g. H2SO4
-10–40% excess to the amount needed for cellulose triacetate formation- DS ~ 3 soluble in CHCl3, e.g.- DS < 3 – products are partly soluble or even insoluble
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Th. Heinze • Friedrich Schiller University of Jena
Cellulose fibers and their structure
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Th. Heinze • Friedrich Schiller University of Jena
Solubility (- insoluble, + soluble) of cellulose acetate- obtained by hydrolysis of cellulose triacetate -
Cellulose acetate
Solvent
DS Chloro-form
Acetone 2-Methoxy-ethanol
Water
2.8-3.0 + – – –2.2-2.7 – + – –
1.2-1.8 – – + –0.6-0.9 – – – +
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Th. Heinze • Friedrich Schiller University of Jena
Cross-section of cellulose acetate filaments, filter tow (light microscope)
Rhodia Acetow Freiburg, Germany
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Th. Heinze • Friedrich Schiller University of Jena
Characteristics and application areas of commercially produced organic esters of cellulose
Cellulose Degree of Content of (wt%) Degree of Typical applications
ester polymerization Acetic acid
Propionic acid/ butyric acid/ phthalic acid
Substitution
Triacetate 150-360 60.0-61.4 -/-/- 2.8-2.0 Coatings, LCD displays, photographic films, isolation foils
Cellulose-2,5-acetate
100-200 55.0-55.5 -/-/- ~2.4 Textile fiber (artificial silk), molding plastics, coatings lacquers, filter tow, thermoplastics
Acetopropionate 150-200 5 57/-/- 0.3-2.3 Thermoplastic compounds
Acetobutyrate 100-150 43 -/18/- 2.1-0.6 Isolated lacquer raw materials, foils
40 -/22/- 2.0-0.7 Foils, films
20 -/44/- 1.0-1.6 Thermoplastic compounds
9 -/59/- 2.0 0.5-2.3 Melt dip resins
Acetophthalate 150-200 24 -/-/35 0.8/1.6 Coatings, enteric coatings, pharmaceuticals
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Th. Heinze • Friedrich Schiller University of Jena
Comments about the characterization
of cellulose esters
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Th. Heinze • Friedrich Schiller University of Jena
5 4 3 2
H-2H-3 H-1, 6
H-6'H-4
H-5
Acetyl-CH3
6 2 3
ppm
OO
OO
O CH3
CH3
O
O
O CH3
123
4 56
1H NMR spectrum of a cellulose triacetate
0 .51 .0
1.01 .52 .0
2.02 .53 .0
3.03 .54 .0
4.04 .55 .0
5.05 .56 .0
ppm
Modified RU
CH3(acetate)
HODDMSO-d6
ORO
ORO
OR
R= CH3(C=O) or H according to DS
1H NMR spectrum of a cellulose acetate (DS 2.37)
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Th. Heinze • Friedrich Schiller University of Jena
Determination of degree of substitution and substitution pattern of cellulose estersafter peracetylation and 1H NMR spectroscopy
2.20 2.00 1.80 2.20 2.00 1.80
Acetyl-CH3
2
3
6
ppm
A) B)
1H NMR spectra of a cellulose acetate A) before and B) after deuteroacetylation
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Th. Heinze • Friedrich Schiller University of Jena
5.0 4.5 4.0 3.5
5.0
4.5
4.0
3.5
H-3 H-2
H-1 H-6
H-6' H-4 H-5
3 2 14ppm
H-3H-2
H-1, 6
H-6' H-4H-5
Propionyl-CH2
Acetyl-CH2
23
6
Propio-nyl-CH3
6 2, 3
ppm
OO
OO
O CH3
CH2CH3
O
O
O CH3
123
4 56
AGU,H
opionylPr,HAcyl H3
I73DS
⋅
⋅−=
AGU,H
opionylPr,HAcyl I3
)n(I71)n(DS
⋅
⋅−=
I= Integral
n= Position 2, 3, or 6
14
1H NMR spectrum (left) and 1H,1H-COSY NMR spectrum (right, the area of the protons of the AGU is displayed)of cellulose acetate propionate prepared by complete propionylation of a commercial cellulose diacetate(CDCl3, 32 scans)
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Th. Heinze • Friedrich Schiller University of Jena
Determination of degree of substitution and substitution pattern of cellulose esters after peracetylation and 1H NMR spectroscopy
15
)(3)(7
AGUIntegralCHLauratIntegralDSEster ∗
−∗= 3
1H NMR spectrum of a peracetylated cellulose laurate (DSLau= 1,52) in CDCl3 at 40°C (16 scans).
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Th. Heinze • Friedrich Schiller University of Jena
Solvents for cellulose
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Th. Heinze • Friedrich Schiller University of Jena
Solvents for Cellulose
Indispensable prerequisite for
i) SHAPINGe.g., fiber spinning applying- N-methylmorpholine-N-oxide monohydrate- CS2/NaOH/H2O
NMNO fiber Viscose fiberTEM of fiber cross-section (Fink et al., 2001)
Viscose- versus NMNO fibers
Structural comparison NMNO 1st generation Viscose (normal)
Cross section shape Round/Oval LobateCross section morphology Homogeneous, dense Core/SkinCrystallinity High Variable
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Th. Heinze • Friedrich Schiller University of Jena
Solvents for Cellulose
Light scattering, Zimm plot of linters in Cd-tren*Burchard et al., Macromolecules 33 (2000) 4094.
*tren = tris-2-aminoethylamine
Indispensable prerequisite for
ii) CHARACTERIZATIONe.g. determination of molar mass and molar mass distribution
[ ])1(1
/)1(−⋅+
−=
reln
rel
Kc
ηηη
Cupriethylenediamine (Cuen) DIN 54270
h
M1
M2
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Th. Heinze • Friedrich Schiller University of Jena
Solvents for Cellulose
Indispensable prerequisite for
iii) HOMOGENEOUS CHEMICAL MODIFICATION
O
HOTDMS-O
O
O-TDMS
a
(THF)
O
OTDMS-O
OH3C
b
(THF)
O
OOH
O
OH
H3C
O-TDMS
O
HOOH
O
OH
O
HOO
O
O+ SiCl
Imidazol
(DMA/ LiCl)
Si
Si
TDMS-Cl
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Th. Heinze • Friedrich Schiller University of Jena
Non-derivatizing solvents Derivatizing solvents
Aqueous media Non-aqueous media
• Aqueous inorganic complexes • Organic solvent/inorganic salt • CF3COOH/(CF3CO)2O
[Cu(NH3)4](OH)2 - Cuam CH3CON(CH3)2/LiCl • HCOOH
[Cu(H2N-(CH2)2-NH2)2](OH)2 - Cuen (CH3)2-SO/CaCl2 • CS2/NaOH
[Cd(H2N-(CH2)2-NH2)3](OH)2 - Cadoxen (CH3)2-SO/(C4H9)4NF
• Aqueous bases • Organic solvent/amine/SO2
10% NaOH (CH3)2-SO/(C2H5)3N/SO2
• Mineral acids • Ammonia/ammonium salt
H2SO4; H3PO4 NH3/NH4SCN
• Melts of inorganic salt hydrates • Oxides of tertiary amines
LiClO4 x 3 H2O
ZnCl2 x 4 H2O • Ionic liquids
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Th. Heinze • Friedrich Schiller University of Jena
13C NMR spectrum of cellulose trifluoroacetate (DS 1.5) in N,N-dimethyl formamide-d7
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Th. Heinze • Friedrich Schiller University of Jena
C-1C-4
C-5C-3
C-2C-6
ppm 100 90 80 70 60
1. Th. Heinze et al., Macromol. Chem. Phys. 201 (2000) 6272. M.C. Vieira, Th. Heinze, Cellulose 9 (2002) 2033. G.T. Ciacco, E. Frollini, Th. Heinze, Cellulose 10 (2003) 125
13C NMR spectrum of Cellulose (3%, w/w) dissolved in dimethylsulfoxide (DMSO)/tetrabutylammonium fluoride, 50 °C, 9.200 scans (peaks below 57 ppm not shown)
OO
OHHO
OH
12
4 56
3
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Th. Heinze • Friedrich Schiller University of Jena
Novel cellulose solvents:
- Dimethyl sulfoxide/tetrabutylammonium fluoride
- Ionic Liquids
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Th. Heinze • Friedrich Schiller University of Jena
Dimethyl sulfoxide/Tetrabutylammonium FluorideTh. Heinze et al., Macromol. Chem. Phys. 201 (2000) 627
DMSO/5-20% Tetrabutylammonium fluoride (TBAF) x 3 H2O
Air-dried cellulose, DP≤650, no pretreatment Cellulose isolated from agave containing 6% hemicellulose xylanAir-dried cellulose from Sisal, DP>650, Activation pretreatment30 min, room temperature, 60 min, 60°C
OOH
OOH
HO123
4
5
6O
OH
OOH
HO123
4
5
6
Solv.
The cellulose dissolves within 15-30 mindepending on DP and concentration
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25Dissolution of cotton fibers visualizedby light microscopy with P. Navard, France
Köhler and Heinze, Macromol. Biosci. 2007, 7,307
Th. Heinze • Friedrich Schiller University of Jena
DMSOPreparation according toSun and DiMagno, J. Am. Chem. Soc. 2005, 127, 2050
Solvents for Cellulose:Anhydrous Tetrabutylammonium Fluoride (TBAF)/DMSO
Cellulose is soluble in this mixture
FF
FF
F
FN +
(DMSO)RT, 1h
N
CNCN
CNCN
NC
NC+
CN F
Dissolution of cotton fibers visualizedby light microscopy
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Th. Heinze • Friedrich Schiller University of Jena
Chemistry of cellulose dissolved in DMSO/TBAFx3H2OApplying esterification agents that tolerate water
R Mol/mol AGU DS
CH3 1.5 0.63CH3 2.3 1.07CH3 10.0 2.72(CH2)2CH3 2.3 0.86(CH2)10CH3 2.3 1.47(CH2)10CH3 10.0 2.60C6H5 2.3 0.95
Conversion of spruce sulfite pulpwith vinyl carboxylic acids(11%TBAF/DMSO, 40°C for 70 h)
Results are comparable with reactions of cellulosedissolved in DMA/LiCl,however, to dissolve the biopolymer inDMSO/TBAF is simple and fast
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27
Ionic Liquids as New Solvents for CelluloseFirst described by Swatloski, Spear, Holbrey, Rogers, JACS 2002, 124, 4974,
WO 03/029393 A2
C & EN / November 8, 2004
Th. Heinze • Friedrich Schiller University of Jena
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Definition of ionic liquids (IL)
N N+
R
N - a l k y l - N - m eth y l -i m i d azo l i u m
N
R
+
N - a l k y l -p y r i d i n i u m
R 4
N +
R 3
R 1
R 2
t et r aal k y l -am m o n i um
R 4
P +
R 3
R 1
R 2
t er taal k y l -p h o sp h on i u m
R 1 ,2 ,3 ,4 = C H 3 (C H 2 ) n , ( n = 1 , 3 , 5 , 7 , 9 ...) ; ar y l ;etc .
C at i o n s :
A n i on s : H 2 O - H 2 O -
[ PF 6 ] -
[ B R 1 R 2 R 3 R 4 ] -
[ B F 4 ] -
[ C F 3 SO 3 ] -[ N O 3 ] -
[ C F 3 C O 2] -
B r - , C l - , I -
solubleinsoluble
Th. Heinze • Friedrich Schiller University of Jena
• Organic salts, melting point under 100°C (sometimes lower, even room temperature).• Non-flammable, highly thermal stability, no measurable vapor pressure• Designer solvents (adapted properties to each problem)
Not really estimated in cellulose chemistry up to now –mainly imidazolium based IL are studied
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Th. Heinze • Friedrich Schiller University of Jena
IL as solvent for cellulose
- Different type of cellulose; DP in the range from 290 to
6500
- Solubility of the cellulose depends on alkyl chain length
n = 0 not soluble
n = 1, 3, 5 soluble
n = 7 extensive swelling
- No degradation of the polymer (sometimes, conditions)
- Non-derivatizing solvent
Recycling of the IL
- Almost complete, without any impurities (Lab-scale
synthesis).
N N+
H3C
X-+
(CH2)nCH3
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Th. Heinze • Friedrich Schiller University of Jena
30
IL used in the studiesN N
+
H3C CH2(CH2)2CH3
Cl -N N
+
H3C CH2CH3
Cl-
1-N-Ethyl-3-methylimidazolium
chloride (EMIMCl) N N+
H3C CH2CH3
Ac -
1-N-Ethyl-3-methylimidazolium
acetate (EMIMAc)N N
+
H3C CH2(CH2)2CH3
Cl-
CH3
1-N-Butyl-2,3-dimethylimidazolium
chloride (BDMIMCl)
N N+
H3C
Cl-
1-N-Allyl-2,3-dimethylimidazolium
chloride (AMIMCl)
1-N-Butyl-3-methylimidazolium
chloride (BMIMCl)
Purity of the IL is a problem, impurities may act as catalystor inhibitor and/or side reactions may occur
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Th. Heinze • Friedrich Schiller University of Jena
DP 350
OHO
OHO
OHO
R'OOR'
O
O R
O
R'=R
OBMIMCl
or H
RCl
O
80°C , 2 h
IL as reaction media: Acylation with acid chloridesD
egre
e of
sub
stitu
tion
0
1
2
3
1/1/2.5 1/3/2.5 1/5/2.5
DS> 0.3soluble in DMSO
DS> 2.0soluble in acetone and chloroform
AGU/Reagent/Pyridine
Pentanoyl chloride Hexanoyl chloride Benzoyl chlorideAcetyl chloride
31T. Heinze, K. Schwikal, S. Barthel, Macromol. Biosci., 2005, 5, 520.
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Synthesis of cellulose furoate with furoyl chloride in various IL,(65°C, 3 h, molar ratio of AGU/pyridine/furoyl chloride of 1/3/3)
OHO
OHO
OH
ORO
ORO
OOCl
O OO
BMIMClPyridine65 °C, 3 h
Ionic Liquid DSBMIMCl 2.43EMIMCl 2.21EMIMAc ??
32
O
EMIMAcPyridine65°C, 3 h
EMIMAcPyridine65°C, 3 h
OHO
OHO
OH
ORO
ORO
OOCl
O CH3
O
CH3R= or H
ORO
ORO
O CH3
O
CH3R= or H
H3C S ClO
O O
Ionic Liquids may be reactive leading to unexpected products, here via formation of the mixed anhydride with the cation
S. Köhler, T. Heinze, Cellulose 14 (2007) 489 Th. Heinze, T. Liebert et al., Macromol. Rapid Commun., 28 (2007) 2311
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Cellulose sulfation in IL
OO
OH
OHHO
OO
OSO3Na
ORRO
SO3NaR:H
SO3-pyridine
BMIMCl/DMF25°C
Water soluble CS above DS 0.25 !
13C NMR spectrum of cellulose sulfate (DS = 0.87) in D2O, recorded at 70°C60.065.070.075.080.085.090.095.0100.0105.0 ppm
C-1
C-2,3,5
C-4
C-6
C-6sulfated
C-1sulfated at C-2 C-2sulfated
• Homogeneous sulfation / co-solvent improves miscibility • DS controlled via amount of sulfating agent• At 25°C reaction temperature, almost no chain degradation• Cellulose sulfate (CS) with adjustable DS and properties (viscosity of solutions)easily accessible• CS forms polyelectrolyte complexes with polycations
33M. Gericke, T. Liebert, T. Heinze, Macromol. Biosci. 2009, 9, 343
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Cellulose sulfation and in-situ formation of polyelectrolyte complexes with water-insoluble CS in IL
4 mm
+
PolyDADMACin water
DS = 0.16, water insolubleEMIMAc
N Cl
n
OOHO
OH
OSO3Na
200 nm
20 µm 100 µm
2 µm
• Water insoluble CS and IL used as solvent• Defined pore structure • Increased mechanical stability
• FTIR and NMR revealed complex formation• Capsules free of IL cation but contain
acetate anions
• Encapsulation of glucose oxidase• Relative enzyme activity (14%) identical
to common PEC capsules
M. Gericke, T. Liebert, T. Heinze J. Am. Chem. Soc. 2009, 131, 1322034
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Novel path for the preparation of cellulose esters
ISBN: 3-540-32103-9
Esterification using in situ activation of the carboxylic acids
CO
OCR
O
NN
NN C
O
NN
+ RCOOHN
NH
DMSO/80°C
-
-+
C
O
RN
NO
O
C
-CO2C
O
RN
N
NNH-
+ PS-OH
PS O
R
O
N,N´-Carbonyldiimidazole (CDI) as activating agent is of particular interest for the esterification Mild conditions Products of high degree of substitution Pure products that can be applied in biomedical applications No polymer degradation
Multifunctional polysaccharide esters by one-pot reaction or step-by-step synthesis strategy
T. Liebert & Th. Heinze Biomacromolecules 2005, 6, 333St. Hornig & Th. Heinze Macromolecular Bioscience 2007, 7, 297
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Examples of polysaccharide esters prepared
36
O
HOOH
OH
OO O
HOOH
OH
O O
HOOH
OH
Cellulose
O
HOOH
OO O
HOO
O O
HOOH
O
HOOH
HOOCO
Xylan
O
HOOH
O
HO
O
O
HOOH
HO
O
O
HOOH
HO
Dextran
NH
OO
Chiral R
OO
Photo-cross-linkable R
OO O
R´s assigned for solubilityS
O
ON3
Reactive R
O
O
O
O
O
O
O
O
O
OO
O
O
Complexing R
Lipophilic polysaccharide derivatives - with a set of funtional groups (R),high degree of substitution (DS) and even complete functionalization
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How to prepare nanoparticles: Dialysis
Slow exchange of the solvent against the non-solvent water
via a cellulose membran, e.g.
Potential solvents: DMA, DMSO, acetone
Pore size of membrane, change of temperature (10 to 80°C)
and stirring during dialysis have no influence on particle size and
the particle size distribution
1 µm
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Th. Heinze • Friedrich Schiller University of Jena
The homogeneous versus the heterogeneous reaction path
Etherification
Mostly, the solvents do not tolerate reagent like NaOH, NaH to initiate the etherification.
Nevertheless, special structures can be synthesized by etherification starting with the dissolved polymer.
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Carboxymethylcellulose (CMC) - Conventional Products
Synthesis
Completely heterogeneous synthesisDSCM = 0.4... 1.3 (one step synthesis)Water- soluble polyelectrolyteNon- toxicWidespread use
50-700C, 3-6h
Aqueous NaOH/ClCH2COONa
Th. Heinze • Friedrich Schiller University of Jena
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Th. Heinze • Friedrich Schiller University of Jena
40
Carboxymethylcellulose (CMC)-Conventional Products
Distribution of Carboxymethyl Groups
Statistic content of the 8 O-2 > O-6 > O-3 different repeating units
1H NMR spectrum of CMC (DSCM = 0.45) HPLC analysis of CMC (DSCM = 0.95)after hydrolysis with D2SO4 / D2O after hydrolysis with HClO4
Macromol. Chem. Phys. 195 (1994) 1483 Angew. Makromol. Chem. 215 (1994) 93
H -1ß(O-2u) O-2α O-2ßH-1α (O-2u)
H-1α (O-2s) H-1ß(O-2s) O-3
O-6
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Th. Heinze • Friedrich Schiller University of Jena
Plot of mole fractions versus DS of CMCsprepared by the conventional process
0,0
0,2
0,4
0,6
0,8
1,0 glucosemono CMGdi CMGtri CMG
Mol
e fra
ctio
n
0,0 0,5 1,0 1,5 2,0 2,5 3,041
DSHPLC
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42
Carboxymethylcellulose (CMC) - New ProductsAlternative Synthesis
Dissolving the polymer Induced Phase Separation Carboxymethylation(e.g. with solid NaOH particles)
ClCH2COONa
10 - 24h, 700C
DSCM = 0.3... 2.1(one-step synthesis)
Appropriate systems FTIR : 1635, 1410 cm-1
(ν COONa)N,N –dimethyl acetamide / LiClN -methylmorpholine-N-oxide / dimethyl sulfoxidecellulose intermediates (formate, trifluoroacetate,trimethylsilyl ether) in dimethyl sulfoxide
J.M.S.-Pure Appl. Chem. A33 (1996) 613Macromol. Symp. 130 (1996) 271
Polarizing light microscopic characterization
Th. Heinze • Friedrich Schiller University of Jena
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0,0
0,2
0,4
0,6
0,8
1,0
Mol
e fra
ctio
n
DS0,0 0,5 1,0 1,5 2,0 2,5 3,0
DMA/LiClTMSC
CFCTFA
CFCTFA
TMSC
TMSC
CA
glucosemono CMGdi CMGtri CMG
CA: cellulose acetateTMSC: trimethylsilyl celluloseCTFA: cellulose trifluoroacetateCF: cellulose formateDMA/LiCl: solution
Plot of mole fractions versus DS of CMC prepared via induced phase separation
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Th. Heinze • Friedrich Schiller University of Jena
44
Carboxymethylcellulose : Enzyme - supported characterization
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Th. Heinze • Friedrich Schiller University of Jena
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46
Turb
idit y
( ar b
it rar
y un
i ts)
Z eta
po t
entia
l (m
V )
Molar ratio of cationic to anionic groups Volume (µl)
Turbidimetric titration of aqueous CMC Zeta potential measurements of a BaSO4
solutions DSCM = 1.7 with poly(diallyl- suspension dependent on addition of dimethylammoniumchlorid) aqueous CMC (New Product, 0.05%)
Cooperation : H.-J. Kötz, University of Potsdam, Germany
Carboxymethylcellulose (CMC) - New ProductsProperties
Commercial CMCAlternative CMC
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47
Carboxymethyl cellulose (300 kt/a)
Methyl- (70 kt/a) and hydroxyalkyl cellulose (54 kt/a)
Ethyl cellulose
Cellulose Ethers – Key Substances in many Applications
Strong interactions by intramolecular- and intermolecular hydrogen bondsActivation of the biopolymer with aqueous NaOH prior the reaction
OO
OHHO
OH
/ Structure
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Functionalization Pattern in Cellulose Derivatives
OH
HO
OHHO
HO HOHO
OHOH
OH
OH
OHOH
OHHO
OH
OH
HOOH
OHOH
OH
OH
HOO
OO
OOO
OO O
OO
O OO
OO
OEt
OEtEtO
OEt
OEt
EtOOEt
OEtOEt
OEt
OEt
EtOHPO
OHPOHP
OHP
OHP
HP: HydroxypropylH3C
OHEt: Ethyl CH2CH3
OO
OHHO
OH
OO
OHHO
OEtO
OOEt
HO
OHO
OOH
EtO
OH
OO
OEtHO
OEtO
OOH
EtO
OEtO
OOEt
EtO
OH
OO
OEtEtO
OEt
Repeating units of ethyl cellulose
Ethylhydroxypropyl cellulose
• Up to 27 differently functionalized repeating units may appear considering the reaction at the hydroxyls at the AGU
• Novel OH group of the hydroxypropyl ether (HP) formed may react as well –further increase of number of repeating units
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Regioselectivity
49
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Protecting group technique: Simultaneous protection of position 2 and 6 with bulky silyl reagents
TDMS-ClImidazol
24 h, 100°C(DMA,LiCl)
O
HOOH
O
OHO
HOO
O
O
Si
Si
A. Koschella, Th. Heinze, D. KlemmMacromol. Biosci. 1 (2001) 49.
1
Th. Heinze, A. Pfeifer, K. PetzoldBioResources 3 (2008) 79.
TBS-ClImidazol
OHO
OO
OSi
Si
OR
TBAF
24 h, 50°C
O
OOH
O
OH
R(Organic solvent)
O
HOO
O
O
Si
Si
R-HalNaH
72 h, 50°C(THF)
O
OO
O
O
Si
SiR
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51
Properties of 3-O-functionalized cellulose ethers: Solubility
Thermoreversible flocculation
Reactive
-+-++
++++++-
Dimethyl sulfoxide
---Propargyl
---Dodecyl
++-Butyl
++-/+Propyl
+-+3’-Hydroxypropyl (X)
+-+Hydroxyethyl (X)
+-+Methoxyethyl (X)
+-+Ethyl (X)
++-iso-Pentyl
---Oligo(Ethylenglycol)
+--Allyl
---Methyl (X)
N,N-Dimethyl acetamide
EthanolWater(20°C)
Sample
Insolubility indicates H-bonds
Thermoreversible flocculation- soluble below 20°C
Reactive
Kadla et al., 2008
(X) – Model compounds of commercially produced cellulose ethers
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Properties of 3-O-functionalized cellulose ethers: Thermoreversible flocculation
52
Cellulose ether Flocculation temperature (°C)
Ethyl cellulose ≈303-mono-O-Ethyl cellulose ≈60
3-mono-O-Methoxyethyl cellulose does not show flocculation at all
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Regioselectivity
Click Chemistry
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Click chemistry – a novel approach to unconventional cellulose products
CuSO4 *5 H2O, sodium ascorbate,dimethyl sulfoxide, 24 h, 25°C
OH
NCH3O
O
OCH3
O
N3OO
OHO
OH OO
OHO
N NN
N
O
OCH3
O
OCH3
OHO
OHO
N3N
O
OCH3
O
OCH3
OHO
OHO
N NN
N
O OCH3
O
OCH3
54
Heinze et al., Macromol. Rapid Commun. 27 (2006) 208-213
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Click chemistry – a novel approach to unconventional cellulose products
O
O OOHO O
N3
O
OH
O
HO OO
OH
O-Na+O
OO-Na+
O-Na+O
12
3
4 56
OO
O-Na+
78
9
10
11
12 Carboxymethyl-6-deoxy-6-azido cellulose, DSAzide 0.81; DSCM 1.25
55
O
OO OHO O
N3
O
OH
O
HO O
OO
HO
O
O
O
OH
+Na-O OO-Na+O
O O-Na+ O-Na+
O
12
3
4 56
OO-Na+
24
25
26
27
28
29
N
HNNH
O O
NN
O
OO
O
NH
HN NHHN
N
N N
N
OCH3
H3CO
O
O
OCH3OCH3
O
OOCH3 OCH3
O O OCH3O
OCH3
O
N N
N7
8 9
10
1112
13
14 15
1617
18
19 2021
2223
Samples are soluble in waterdue to the additional ionic groups
Dendronization via Click chemistryHomogeneous approach(Water)
Heinze et al., European Polymer Journal 45 (2009) 1098
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Click chemistry – a novel approach to unconventional cellulose products – biofunctionalization
OHO O
OH
N
HNNH
O
N N
O
NH
ONH HN
OO
HN
NN
N
NH2 H2N NH2 H2N
OHO O
N3
OHO
CuSO4*5H2O,sodium ascorbate
DSTriazole 0.25
DSAzide 0.75
N
HNNH
O
N N
O
NH
ONH HN
OO
HN
NH2 H2N NH2 H2N
O
+
(DMSO), rt, 24 h
1
2
3
6-deoxy-6-(1,2,3-triazolo)-4-polyamidoamine (PAMAM)cellulose of 2.5th generationobtained by copper-catalyzedHuisgen reaction (Click Chemistry)
563500 3000 2500 2000 1500 1000 500
Wave number [cm-1]
OH
N3 C-O-C
NH2
-NH-CH2
-OCNH-
A
B N3
3500 3000 2500 2000 1500 1000 500
Wave number [cm-1]
OH
N3 C-O-C
NH2
-NH-CH2
-OCNH-
A
B N3
a) Reaction can be carried outat membrane of6-deoxy-6-azido cellulose
ATR/IR spectra of films ofA) deoxy-azido cellulose andB) after surface modification with propargyl-PAMAM dendron of 2.5th generation via copper-catalyzedHuisgen reaction
Heterogeneous approach
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A novel type of structure forming polymers: Amino cellulose
Biofunctionalized surfaces with amino cellulose
NH
NH
Bifunctional coupling reagent
NH2
“Biofunction”
Substrate material
Aminocellulose-monolayerSelf-assembling
“Adhesive interactions”
(spacer)
NH2
Bifunctional coupling reagent
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Click chemistry – a novel approach to unconventional cellulose products – biofunctionalization
NH2 Amount Specific Activity (nmol/cm²) (mU/cm²)
71.34 135.16
58
(Methanol), 3 h, 25°C
Propargyl-PAMAM Dendron (2,5. Gen.) Cu(I)-Katalysator
Glukoseoxidase
NN
NN
NN
NN
N
Glutar-dialdehyd
N
NH HN
O
NNO
HN
OHNNH
O O
NH
NN
N
H2NNH2H2NNH2
O
N3
N3
N
OH
H
N3
N3
GOD
N
NH
H
N3
N3
Dendronisierung
Relative enzyme activity:Arel=Aimmobilized/Adissolved = 27.2%
M. Pohl, N. Michaelis, F. Meister, Th. Heinze, Biomacromolecules 10 (2009) 382
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Summary
Organic chemistry with cellulose is one of themost important tools to design novel materialsbased on the most important renewable resourcecellulose.
Organic chemistry is a fascinating work.
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Acknowledgements
60
PhD- andDiploma Students
Postdocs/Scientific coworkers
Technicians
Scientific coworkers
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AcknowledgementsCenter of Electron Microscopy, FSU Jena
Institute of Pharmaceutical Technology, FSU Jena
German Science Foundation
Thank you very much for you kind attention
European Union
Funds of the Chemical Industry of Germany
61