环己烷-乙醇-离子液体液液相平衡数据测定及关联

Measurement and correlation of liquid-liquid equilibrium data for cyclohexane-ethanol-ionic liquids

环己烷-乙醇是化工生产中常见的共沸体系,溶剂萃取是分离环己烷-乙醇的重要途径。在常压,303.15 K实验条件下,以[EMIM][OTF](1-乙基-3-甲基咪唑三氟甲烷磺酸盐)、[EMIM][SCN](1-乙基-3-甲基咪唑硫氰酸盐)、[EMIM][DCA](1-乙基-3-甲基咪唑双氰胺盐)3种离子液体为萃取剂,测定环己烷-乙醇的液液相平衡数据。利用分配系数和选择性评价不同离子液体的萃取性能。此外,根据Othmer-Tobias和Hand方程对相平衡实验数据进行一致性和可靠性校验。最后,采用Aspen Plus软件选择NRTL模型对相平衡数据进行关联,获得二元交互作用参数,并将其用于计算相应的相平衡组成。通过研究发现,计算值和实验值的均方根偏差小于0.02,表明NRTL模型能够准确描述三元相平衡过程。

A cyclohexane-ethanol mixture is a common azeotropic system in the production of chemical production.Solvent extraction is an important way to separate cyclohexane-ethanol mixtures.Under the experimental conditions of atmospheric pressure and 30 ℃,three kinds of ionic liquids,namely [EMIM][OTF](1-ethyl-3-methylimidazole trifluoromethane sulfonate),[EMIM][SCN](1-ethyl-3-methylimidazole thiocyanate) and [EMIM][DCA](1-ethyl-3-methylimidazolium dicyandiamide) were used as extractants to obtain the liquid-liquid equilibrium data for the system of cyclohexane-ethanol.The extraction performance of different ionic liquids was evaluated by the distribution coefficient and selectivity.Besides,the consistency and reliability of the phase equilibrium experimental data were verified according to the Othmer-Tobias and Hand equations.Finally,Aspen Plus software was used to select the NRTL model to correlate the phase equilibrium data and obtained the binary interaction parameters,which were used to calculate the corresponding phase equilibrium composition.The root mean square deviation between the calculated value and the experimental value is less than 0.02 through the above research,indicating that the NRTL model can describe the ternary phase equilibrium process accurately.