Continuous Esterification of n-Butyl Acetate Catalyzed by Ionic Liquid

Abstract

An ionic liquid, 2-Pyrrolidonium hydrogen sulfate (IL, [Hnhp]HSO4) together with a rectification column, was applied in continuous preparation of n-butyl acetate (n-BuAc) from n-butanol (n-BuOH) and acetic acid (HAc). [Hnhp]HSO4 was used as a catalyst which showed good activity for the esterification. Optimum conditions were as follows: base fluid n(HAc):n(n-BuOH): n(IL) =6:1:0.3 in reactor at 120 °C, feedstock n(n-BuOH):n(HAc) =1.05:1 by feeding to the reactorat 20 mL·h-1, aqueous reflux 18 mL·h-1 by feeding to the upper segment of the column and reflux ratio 1. During 48 hours of continuous reaction time, n-BuAc content ranged from 97 % to 85 % in the ester phase from overhead liquid-liquid separator and the reactive distillation system could maintain a good balance.