Reactivity of Brönsted acid ionic liquids as dual solvent and catalyst for Fischer esterifications

Zuojun Wei, Feijin Li, Huabin Xing, Shuguang Deng, Qilong Ren

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)666-672
Number of pages7
JournalKorean Journal of Chemical Engineering
Issue number3
StatePublished - May 2009
Externally publishedYes


  • Brönsted Acid Catalyst
  • Fischer Esterification
  • Ionic Liquid
  • Reaction Kinetics
  • Water Content

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering


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