Separation of the Methanol–Ethanol–Water Mixture Using Ionic Liquid

Abstract

Vapor pressure data for the binary systems (water/methanol/ethanol + 1-ethyl-3-methylimidazolium acetate ([EMIM]+[Ac]−)) and the ternary systems (methanol + water + [EMIM]+[Ac]−, ethanol + water + [EMIM]+[Ac]−, and methanol + ethanol + [EMIM]+[Ac]−) were measured by a modified equilibrium still. For the above systems, the maximum average relative deviation between experimental data and the UNIFAC-Lei model predicted values was 7%, confirming the prediction accuracy of the UNIFAC-Lei model. Thus, this model was further used to predict the isobaric vapor–liquid equilibrium (VLE) data at 101.3 kPa for the methanol + water + [EMIM]+[Ac]−, ethanol + water + [EMIM]+[Ac]−, and methanol + ethanol + [EMIM]+[Ac]− systems at a fixed mole fraction of ionic liquid (IL) (xIL = 0.2). It was demonstrated that the ionic liquid [EMIM]+[Ac]− was an appropriate entrainer to separate the methanol–ethanol–water mixture. On this basis, the extractive distillation process was simulated using the rigorous equilibrium (EQ) stage m...