甲醇-甲乙酮-1-乙基-3-甲基咪唑双三氟甲磺酰亚胺盐物系等压汽液相平衡数据的测定及分析

考察了离子液体1-乙基-3-甲基咪唑双三氟甲磺酰亚胺盐（EMIM]NTf₂]）对甲醇-甲乙酮共沸物系等压汽液相平衡的影响。首先测得了101.3 kPa下甲醇-甲乙酮-EMIM]NTf₂]三元体系的等压汽液相平衡数据，然后用非随机双液（NRTL）模型进行了关联，平均相对偏差为1.39%，表明了NRTL模型对含离子液体三元体系的良好适用性。经NRTL模型计算，在EMIM]NTf₂]的摩尔分数为0.047时可消除甲醇-甲乙酮共沸点。实验结果表明：EMIM]NTf₂]的加入对甲醇-甲乙酮体系表现出极强的盐效应，改变了体系的汽液相平衡，提高了甲醇对甲乙酮相对挥发度。因此EMIM]NTf₂]可作为甲醇-甲乙酮萃取精馏的萃取剂。

Isobaric vapor-liquid equilibrium for methanol+methyl ethyl ketone+1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide

The isobaric vapor-liquid equilibrium (VLE) data for the ternary system methanol+methyl ethyl ketone (MEK)+1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM]NTf₂]) were obtained at 101.3 kPa. The VLE data were correlated by the NRTL model with ARD=1.39%, which indicates that the NRTL model has a good applicability to systems containing ionic liquids (IL). The experimental results showed that EMIM]NTf₂] had a strong salt effect on the VLE behavior of the azeotropic system and enhanced the volatility of methanol relative to MEK. The azeotrope of methanol and MEK could be eliminated when the mole fraction of EMIM]NTf₂] in the liquid phase was more than 0.047, as calculated by the NRTL model. EMIM]NTf₂] can thus serve as a good entrainer for the separation of methanol and MEK in extractive distillation.