Kinetic study and process simulation of esterification of acetic acid and ethanol catalyzed by [HSO3-bmim][HSO4

Abstract

Ethyl acetate is an important chemical and versatile organic solvent. However, use of hazardous catalyst for preparing ethyl acetate, can lead to serious environmental problems. Herein we report two acid sites containing ionic liquid i.e. 1-sulfobutyl-3-methylimidazolium hydrogen sulfate ([HSO3-bmim][HSO4]) as a green catalyst in the esterification of acetic acid with ethanol. The reaction kinetics was investigated using IH and NIH models and the effect of reaction temperature, catalyst concentration, and initial reactant molar ratio were analyzed. To study the industrialization prospect of [HSO3-bmim][HSO4], reactive distillation process was established in Aspen Plus and the influence of catalyst amount, theoretical stages, reflux ratio, liquid holdup, and ethanol feeding location were investigated. Simulation results indicated the purity of ethyl acetate was 98.94wt.% while ethanol conversion was 91.51% under optimized operating conditions. [HSO3-bmim][HSO4] was found as superior catalyst, both in conversion and reaction rate, than an equivalent amount of Amberlyst 15 (in terms of H+ ion concentration). The present study based on the application of [HSO3-bmim][HSO4] as a green catalyst instead of sulfuric acid, can be envisaged as a promising alternative approach for the esterification of acetic acid on industrial level.