乙醇-水-离子液体三元体系的气液平衡测定及其萃取精馏试验

在101.32 kPa下,用改进的Othmer釜测定了乙醇-水-1,3-二甲基咪唑磷酸二甲酯盐([MMIM]+[DMP]-)物系等压气液平衡数据。实验结果表明,加入[MMIM]+[DMP]-使气液平衡线偏离乙醇-水二组分物系的气液平衡线,[MMIM]+[DMP]-含量越高,偏离程度越大;[MMIM]+[DMP]-表现出盐效应,使乙醇对水的挥发度发生改变,消除了乙醇-水物系的共沸点;并以[MMIM]+[DMP]-作为乙醇-水物系萃取精馏的溶剂,进行了萃取精馏的小型工艺试验,结果塔顶乙醇质量分数达到99.5%,能够满足工业要求。

Vapor-liquid equilibrium and extractive distillation for ethanol-water-ionic liquids ternary system

Isobaric vapor-liquid equilibrium data for ethanol-water-+-ternary systems were measured at 101.32 kPa using modified Othmer still.The experimental results indicate that the vapor-liquid equilibrium curves of the ethanol-water-ionic liquid(IL) systems deviate from that of the IL-free system and the deviation increases with increasing amounts of IL.The ionic liquid shows a salt-out effect,which increases the relative volatility of ethanol to water,and even leads to an elimination of the azeotropic point.+-can be used as the solvent of ethanol-water system for extractive distillation.The small extractive distillation process test was carried out as well.The purity of ethanol at top of the tower reaches 99.5%,which can meet the requirement of industry.