基于UNIFAC模型的离子液体相平衡及萃取研究

Phase equilibria and extraction of ionic liquids based on the universal functional activity coefficient model(UNIFAC)

通过拟合季膦类、咪唑类离子液体中无限稀释的苯和醇类等溶质的实验数据,得到了离子液体中[TRP][BF4]等7种新主基团的UNIFAC(universal functional activity coefficient)模型参数。基于该参数,预测了乙醇和甲醇在离子液体[EMIM][ES]和[BMIM][C5H12O6S]中的气液相平衡,计算值与实验结果之间吻合较好,这表明本文中仅使用无限稀释溶液活度系数回归出的UNIFAC模型参数仍然是可靠的。最后,对4种离子液体在甲苯/苯-乙醇/甲醇体系中的萃取性能进行了筛选,发现[BMIM][C5H12O6S]在甲苯/苯-醇类体系的萃取选择性最高,达到15.3。

Universal functional activity coefficient （UNIFAC） model parameters of seven novel groups such as trihexyl（tetradecyl） phosphonium tetrafluoroborate （ [ TRP ] [ BF4 ] ） have been regressed by fitting the experimental activity coefficients at infinite dilute of benzene and alcohols in phosphonium halide and imidazole ionic liquids. Based on these model parameters, the vapor-liquid phase equilibria of ethanol and methanol in 1-ethyl-3-methylimidazolium ethylsulfate （ [ EMIM ] [ ES ] ） and 1-butyl-3-methylimidazolium 2-（2-methoxyethoxy） ethyl sulfate （ [ BMIM] [ C5H12O6S] ） were predicted. Good agreement between calculation and experiment was obtained, indicating that our UNIFAC model parameters fitted only from the activity coefficients at infinite dilution of solutes are reliable. Finally, the extraction performance of four ionic liquids in toluene/benzeneethanol/methanol systems was screened. [ BMIM] [ C5H12O6S] showed the greatest extractive selectivity, reaching a maximum of 15.3, and was thus selected as an optimal extractant.