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CoSMoS 2013 Eutectic Solvents Douglas Raynie
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Explorations With Deep Eutectic Solvents For Chemical Extractions
Douglas E. Raynie
Department of Chemistry and Biochemistry South Dakota State University [email protected]
Green Chemistry
Supercritical Fluid
Technology
Analytical Separations Bioprocessing
Chemical Problem Solving
Environmental Analysis
Fundamental Studies
DIFFUSION COEFFICIENT SUMMARY
DECREASING THE IMPACT OF SOLVENTS 1.Reduce the volume of solvent
use higher concentra/ons use solvent for more than one step
2. Make the solvents greener
carefully chosen conven/onal solvents new green solvents
GREEN SOLVENTS
We know guidelines such as like dissolves like, but when it comes to green solvents, how will we
recognize one when we see it?
General Guidelines for PredicHng the Toxicity of Solvents As the number of alipha/c carbons increases, toxicity increases up to about eight carbons. Including subs/tu/ons, toxicity increases as molecular weight increases up to eight carbons. As the number of carbon-carbon double bonds increases, toxicity increases. As the degree of halogena/ons increases, toxicity increases. Brominated compounds are more toxic than chlorinated, which are more toxicity than uorinated. These same general statements are true for alipha/c subs/tu/on on aroma/c compounds. Subs/tu/on of aroma/cs increases toxicity. Subs/tu/on on phenols para- or ortho-, para- to the hydroxyl are more toxic.
PROPERTIES OF CONCERN For greenness boiling point/energy to dis/ll ash point cumula/ve energy demand For uHlity polarity basicity/hydrogen-bond accep/ng ability acidity/hydrogen-bond dona/ng ability viscosity
C. Capello, U. Fischer, and K. Hungerbuhler, Green Chem., 9, 927-934 (2007).
WHAT IS A GREEN SOLVENT?
GSK SOLVENT SELECTION GUIDE
C. Jimenez-Gonzalez, A. D. Curzons, D. J. Constable, and V. L. Cunningham, J. Clean Technol. Environ. Policy, 7, 42-50 (2005).
PFIZER MEDICINAL CHEMISTRY SOLVENT SELECTION GUIDE
Preferred Usable Undesirable
Water Cyclohexane Pentane Acetone Toluene Hexane(s)
Ethanol Methylcyclohexane Di-isopropyl ether 2-Propanol TBME Diethyl ether
1-Propanol Isooctane Dichloromethane Heptane Acetonitrile Dichloroethane
Ethyl acetate 2-Me THF Chloroform Isopropyl acetate THF NMP Methanol Xylenes DMF
MEK DMSO Pyridine 1-Butanol Acetic acid DMAc
t-Butanol Ethylene glycol Dioxane Dimethoxyethane
PFIZER SOLVENT REPLACEMENT TABLE Red Solvents Alternative
Pentane Heptane Hexane(s) Heptane Di-isopropyl ether or ether 2-MeTHF or t-Butyl methyl ether Dioxane or dimethoxyethane 2-MeTHF or t-Butyl methyl ether Chloroform, dichloroethane or carbon tetrachloride
DCM
DMF, NMP or DMAc Acetonitrile Pyridine Et3N (if pyridine used as base) DCM (extractions) EtOAc, MTBE, toluene, 2-MeTHF DCM (chromatography) EtOAc/Heptanes Benzene Toluene
Deep Eutectic Solvents (DES)
Diagrammatic representation of how HBD interacts with a QAS
Eutectic mixtures of quaternary ammonium salts (QAS) and hydrogen bond donors (HBD)
Bulky cations and smaller anions which are bound to a HBD
Abbott, A. P.; Boothby, D et al.; J. Am. Chem. Soc., 2004, 126 (29), 9142-9147.
Choline chloride-Urea (1:2) Choline chloride melts at
302C and urea melts at 133C Molar ratio of choline chloride
to urea is 1:2 The eutectic mixture melts at
12C The depression in freezing
point is 178C
Andrew P. Abbott.; Glen Capper et al.; Chem. Eur. J., 2004, 10, 3769-3774
Choline chloride-Urea
Synthesis General formula
(R1R2R3R4N+) (X-) (R5) (YH) A B C D 106 combinations Not possible to study all the combinations QAS: HBD: Choline chloride Acetylcholine chloride Urea Glycerol
N+
HO
Cl- N+
O
O
Cl-H2N
O
NH2
OH
HO
OH
Andrew P. Abbott.; Glen Capper et al.; Chem. Eur. J., 2004, 10, 3769-3774
Synthesis 16 different combinations of DES were synthesized by
changing the QAS, HBD, and their composition Binary:
QAS+HBD (4 combinations)
Ternary:
QAS+HBD+HBD (6 combinations)
QAS+QAS+HBD (6 combinations)
Components Composition Choline chloride: Urea 1:2
Choline chloride: Glycerol 1:2
Acetyl choline chloride: Urea 1:2
Acetyl choline chloride: Glycerol 1:2
Choline chloride: Urea: Glycerol 1:1:1
Choline chloride: Urea: Glycerol 2:3:1
Choline chloride: Urea: Glycerol 2:1:3
Acetyl choline chloride: Urea: Glycerol 1:1:1
Acetyl choline chloride: Urea: Glycerol 2:3:1
Acetyl choline chloride: Urea: Glycerol 2:1:3
Choline chloride: Acetyl choline chloride: Urea 1:1:4
Choline chloride: Acetyl choline chloride: Urea 1:2:6
Choline chloride: Acetyl choline chloride: Urea 2:1:6
Choline chloride: Acetyl choline chloride: Glycerol 1:1:4
Choline chloride: Acetyl choline chloride: Glycerol 1:2:6
Choline chloride: Acetyl choline chloride: Glycerol 2:1:6
QAS+HBD (4combinations)
QAS+HBD+HBD (6 combinations)
QAS+QAS+HBD (6 combinations)
Phase Properties
Tc range from -37C to -15C Tm range from 12C to 25C Tc and Tm values of DES were far less than the
corresponding QAS and HBD used in their synthesis Tdecomp (10%) range from 186C to 208C
Viscosity Range from 5.4294 x 10-1 Pa.sec to 0.9243 x 10-2 Pa.sec As the choline chloride concentration increased, viscosity
decreased Viscosity studied as a function of temperature from 25C
-150C, with increasing temperature viscosity decreased
Range from 1.1684 g/mL to 1.264 g/mL As the glycerol concentration increased, density increased
Density
pH
Range from 10.44 to 5.42 As the acetylcholine chloride concentration increased, pH
decreased As the urea concentration increased, pH increased
Kow Range from 0.061 to 0.141 As the glycerol concentration increased, Kow increased
RefracHve Index
Ranges from 1.43-1.51 Relates to polarity (water is 1.33)
Choline Chloride
Urea
Glycerol
1:2 Choline Chloride: Urea
1:2 Choline Chloride: Glycerol
1:1:1 Choline Chloride:Urea: Glycerol
Water S S S S S S
Acetone IS IS IS IS IS IS
Acetonitrile IS IS IS IS IS IS
Methanol S S S S S S
Ethanol S S S S S S
Isopropanol IS IS S IS S IS
Dichloromethane IS SS IS IS IS IS
Chloroform SS SS IS IS IS IS
DMSO SS S S S S S
Pentane IS IS IS IS IS IS
Hexane IA IS IS IS IS IS
Toluene IS IS IS IS IS S
Miscibility with Common Solvents
S= soluble SS = slightly soluble IS = insoluble
DES soluble with polar solvents
*
Cyclohexane 0 0 0
Benzene 0 0.1 0.59
Acetonitrile 0.19 0.31 0.75
Water 1.17 0.47 1.09
1:2 Choline Chloride:Urea
0.734 0.632 0.987
1:2 Choline Chloride:Glycerol
0.927 0.642 0.979
1:1:1 Choline Chloride:Urea:Glycerol
0.917 0.765 0.985
= acidity, H-bond dona/ng ability = basicity, H-bond accep/ng ability * = polarity and polarizability
Kamlet-TaQ Solvatochromic Parameters
DES
DES
DES
DES
Dissolution of Sugars
Glucose Sucrose Dextrose Xylose
1:2 Choline chloride: Urea
Soluble Soluble Soluble Soluble
1:2 Choline chloride: Glycerol
Soluble Soluble Soluble Soluble
1:2 Acetyl choline chloride: Urea
Soluble Soluble Soluble Soluble
1:2 Acetyl choline chloride: Glycerol
Soluble Soluble Soluble Soluble
Naturally Occurring DES 1:2, 1:3 Citric Acid:Choline Chloride 1:1, 1:2, 1:3 Malic Acid:Choline Chloride 1:1, 1:2, 1:3 Maleic Acid:Choline Chloride 1:1 Aconi/c Acid:Choline Chloride 1:1:1 Glucose:Choline Chloride:Water 1:1:1 Fructose:Choline Chloride:Water 1:1:1 Sucrose:Choline Chloride:Water 1:1, 1:2, 1:3 Citric Acid:Proline 1:1 Malic Acid:Glucose 1:1 Malic Acid:Fructose 1:1 Malic Acid:Sucrose 2:2 Citric Acid:Glucose 2:1 Citric Acid:Trehalose 1:1 Citric Acid:Sucrose
4:1 Maleic Acid:Glucose 1:1 Maleic Acid:Sucrose 1:1 Glucose:Fructose 1:1 Fructose:Sucrose 1:1 Glucose:Sucrose 1:1:1 Sucrose:Glucose:Fructose
Plant Physiology 156: 1701-1705 (2011).
Analy.cal Chemistry 85: 6272-6278 (2013).
CONCLUSIONS
Deep eutec/c solvents comprise a class of novel, green solvents suitable for separa/ons and other chemical processes.