Mixed ionic liquids have excellent physicochemical properties; therefore, they are increasingly used in academic research. The separation of mixed ionic liquids is a key problem for the recycle of ionic liquids, and liquid–liquid extraction is an effective process to separate mixed ionic liquids. The COSMO-SAC model was used to screen solvents to separate the ionic liquid mixture 1-octyl-3-methylimidazolium tetrafluoroborate ([C₈mim][BF₄]) + 1-ethyl-3-methylimidazolium tetrafluoroborate ([C₂mim][BF₄]) by liquid–liquid extraction, and water is selected as solvent. The liquid–liquid equilibrium (LLE) data for the ternary system of [C₈mim][BF₄] + [C₂mim][BF₄] + water were measured at temperatures of 298.15, 308.15, and 318.15 K under atmospheric pressure. The experimental LLE data were well correlated by the nonrandom two-liquid model. The experimental results show that water is an effective solvent for the separation of the ionic liquid mixture of [C₈mim][BF₄] and [C₂mim][BF₄].

中文翻译：

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三元体系1-辛基-3-甲基咪唑鎓四氟硼酸盐+1-乙基-3-甲基咪唑鎓四氟硼酸盐+水的液-液平衡的测量和关联

混合离子液体具有优异的理化性能；因此，它们越来越多地用于学术研究。混合离子液体的分离是离子液体回收利用的关键问题，液液萃取是分离混合​​离子液体的有效工艺。采用COSMO-SAC模型筛选溶剂，分离离子液体混合物1-辛基-3-甲基咪唑鎓四氟硼酸盐([C ₈ mim][BF ₄ ])+1-乙基-3-甲基咪唑鎓四氟硼酸盐([C ₂ mim]) [BF ₄ ])通过液-液萃取，选择水作为溶剂。在大气压下，在298.15、308.15和318.15 K温度下测量了[C ₈ mim][BF ₄ ] + [C ₂ mim][BF ₄ ] +水三元体系的液液平衡（LLE）数据。实验 LLE 数据与非随机双液模型具有良好的相关性。_{实验结果表明，水是分离[C 8} mim][BF ₄ ]和[C ₂ mim][BF ₄ ]离子液体混合物的有效溶剂。