Isobaric Vapor–Liquid Equilibrium for 2-Butanone + Ethanol System Containing Different Ionic Liquids at 101.3 kPa

Abstract

In this work, ionic liquids (ILs) were selected as extractive distillation entrainers to separate the 2-butanone + ethanol binary azeotropic mixture because of their remarkable molecular designability, high selectivity, low volatility, and other excellent characteristics. The isobaric vapor–liquid equilibrium (VLE) data for the ternary systems of 2-butanone + ethanol + acetate-based ILs (1-ethyl-3-methylimidazolium acetate [EMIM][OAC], 1-butyl-3-methylimidazolium acetate [BMIM][OAC], and 1-hexyl-3-methylimidazolium acetate [HMIM][OAC]) were measured at 101.3 kPa in an all-glass dynamic recirculating still. The addition of ILs can significantly enhance relative volatility of 2-butanone to ethanol, and the azeotropy of the 2-butanone + ethanol binary mixture is eventually eliminated by increasing the IL content to a certain value. The separation efficiency of the three ILs follows the order [EMIM][OAC] > [BMIM][OAC] > [HMIM][OAC]. Additionally, the binary and ternary VLE data are well-correlated with the nonrandom two-liquid model.