TY - JOUR
T1 - Reactivity of Brönsted acid ionic liquids as dual solvent and catalyst for Fischer esterifications
AU - Wei, Zuojun
AU - Li, Feijin
AU - Xing, Huabin
AU - Deng, Shuguang
AU - Ren, Qilong
N1 - Funding Information:
The authors gratefully acknowledge the support from the National Natural Science Foundation of China (No. 20506023), Zhejiang Provincial Natural Science Foundation (No. Y406250), the Foundation of the “Top Disciplines” of Zhejiang province in China, and the Foundation of the “State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology”.
PY - 2009/5
Y1 - 2009/5
N2 - Several water-stable ionic liquids with different acidity and affinity were synthesized and applied as both solvents and acid catalysts for Fischer esterification of ethanol reacting with four aliphatic carboxylic acids (acetic acid, n-hexanoic acid, lauric acid, and stearic acid). Among the studied ionic liquids, [(n-bu-SO3H) MIM][HSO4] (3-butyl-1-(butyl-4- sulfonyl) imidazolium sulfate) and [(n-bu-SO3H) MIM][p-TSO] (3-butyl-1-(butyl-4-sulfonyl) imidazolium toluenesulfonate) show higher reactivity for the production of ethyl esters. The catalytic activities of these ionic liquids are strongly dependent on the acidity of their anions and cations, as well as their hydrophilicity and affinity with the reactants. Water refluxing through the condenser may be another important reason for obtaining high conversion of esterification, indicating a water-sequester process is still needed in order to obtain a higher yield of ester in the ionic liquid catalyzed esterification system. Kinetics studies show the conversions of the acids increase with reaction temperature and time, and reach equilibrium within about two hours. The apparent activation energies are 39.1±2.0, 49.7±2.5, 51.4±2.5 and 59.3±3.0 kJ•mol-1 for the formation of ethyl acetate, ethyl n-hexanoate, ethyl laurate and ethyl stearate, respectively.
AB - Several water-stable ionic liquids with different acidity and affinity were synthesized and applied as both solvents and acid catalysts for Fischer esterification of ethanol reacting with four aliphatic carboxylic acids (acetic acid, n-hexanoic acid, lauric acid, and stearic acid). Among the studied ionic liquids, [(n-bu-SO3H) MIM][HSO4] (3-butyl-1-(butyl-4- sulfonyl) imidazolium sulfate) and [(n-bu-SO3H) MIM][p-TSO] (3-butyl-1-(butyl-4-sulfonyl) imidazolium toluenesulfonate) show higher reactivity for the production of ethyl esters. The catalytic activities of these ionic liquids are strongly dependent on the acidity of their anions and cations, as well as their hydrophilicity and affinity with the reactants. Water refluxing through the condenser may be another important reason for obtaining high conversion of esterification, indicating a water-sequester process is still needed in order to obtain a higher yield of ester in the ionic liquid catalyzed esterification system. Kinetics studies show the conversions of the acids increase with reaction temperature and time, and reach equilibrium within about two hours. The apparent activation energies are 39.1±2.0, 49.7±2.5, 51.4±2.5 and 59.3±3.0 kJ•mol-1 for the formation of ethyl acetate, ethyl n-hexanoate, ethyl laurate and ethyl stearate, respectively.
KW - Brönsted Acid Catalyst
KW - Fischer Esterification
KW - Ionic Liquid
KW - Reaction Kinetics
KW - Water Content
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U2 - 10.1007/s11814-009-0111-0
DO - 10.1007/s11814-009-0111-0
M3 - Article
AN - SCOPUS:65949112708
SN - 0256-1115
VL - 26
SP - 666
EP - 672
JO - Korean Journal of Chemical Engineering
JF - Korean Journal of Chemical Engineering
IS - 3
ER -