乙醇-碳酸甲乙酯-离子液体体系液液相平衡数据的测定及关联

Determination and correlation of liquid-liquid equilibrium data of ethanol-methyl ethyl carbonate-ionic liquid systems

在常压、303.15 K条件下,以离子液体(IL)1-乙基-3-甲基咪唑磷酸二氢盐([EMIM][DHP])、1-丙基-3-甲基咪唑磷酸二氢盐([PMIM][DHP])、1-丁基-3-甲基咪唑磷酸二氢盐([BMIM][DHP])为萃取剂,测定了乙醇-碳酸甲乙酯(EMC)-IL体系的液液相平衡(LLE)数据,分别计算了不同IL对乙醇-EMC体系的分配系数和选择性系数,并研究了IL对乙醇-EMC共沸体系相平衡行为的影响。采用Aspen Plus软件中的NRTL模型对乙醇-EMC-IL体系的LLE数据进行模型关联,得到相应的非随机参数和二元相互作用参数,为IL萃取分离乙醇-EMC的工艺设计奠定基础。实验结果表明,以[EMIM][DHP],[PMIM][DHP],[BMIM][DHP]为萃取剂分离乙醇-EMC共沸体系的选择性系数均大于1,3种ILs都具有良好的分离效果,其中,[EMIM][DHP]的选择性系数最高;采用NRTL模型关联得到的计算值与实验值的均方根偏差小于5%,表明NRTL模型关联乙醇-EMC-ILs三元体系的LLE数据准确性较好。

Using ionic liquids(IL)1-ethyl-3-methylimidazole dihydrogen phosphate([EMIM][DHP]),1-propyl-3-methylimidazole dihydrogen phosphate([PMIM][DHP])and 1-butyl-3-methylimidazole dihydrogen phosphate([BMIM][DHP])as extractants,the liquid-liquid equilibrium(LLE)data of ethanol-methyl ethyl carbonate(EMC)-IL system were determined at atmospheric pressure and 303.15 K.The distribution coefficients and selectivity coefficients of different ILs for the ethanol-EMC system were calculated respectively,and the effect of IL on the phase equilibrium behavior of the ethanol-EMC azeotropic system was studied.The NRTL model in Aspen Plus software was used to correlate the LLE data of the ethanol-EMC-IL system,and the corresponding non-random parameters and binary interaction parameters were obtained,laying the foundation for the process design for ethanol-EMC separation with IL.The experimental results show that the selectivity coefficients of ethanol-EMC azeotrope systems using[EMIM][DHP],[PMIM][DHP],[BMIM][DHP]as extractant are all greater than 1,and the selectivity coefficients of[EMIM][DHP]are the highest.The root-mean-square deviation between the calculated values and the experimental values using the NRTL model is less than 5%,indicating that the accuracy of the LLE data of ethanol-EMC-ILs ternary system is good.