Chinese Journal of Chemical Engineering, Vol.28, No.3, 766-776, 2020
Effects of imidazolium-based ionic liquids on the isobaric vapor-liquid equilibria of methanol plus dimethyl carbonate azeotropic systems
The separation of methanol (MeOH) and dimethyl carbonate (DMC) is important but difficult due to the formation of an azeotropic mixture. In this work, isobaric vapor-liquid equilibrium (VLE) data for the ternary systems containing different imidazolium-based ionic liquids (ILs), i.e. MeOH + DMC + 1-butyl-3-methy-limidazolium bis[(trifluoromethyl)sulfonyl]imide ([Bmim][Tf2N]), MeOH + DMC + 1- ethyl-3-methyl-imidazolium bis [( trifluoromethyl)sulfonyl]imide ([Emim][Tf2N]), and MeOH + DMC + 1-ethyl-3-methylimidazolium hexafluorophosphate ([Emim][PF6])) were measured at 101.3 kPa. The mole fraction of IL was varied from 0.05 to 0.20. The experimental data were correlated with the NRTL and Wilson equations, respectively. The results show that imidazolium-based ILs were beneficial to improve the relative volatility of MeOH to DMC, and [Bmim][Tf2N] showed a much more excellent performance on the activity coefficient of MeOH. The interaction energies of system componentswere calculated using Gaussian program, and the effects of cation and anion on the separation coefficient of the azeotropic system were discussed. (C) 2019 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.