乙酸乙酯-乙醇-离子液体等压汽液平衡数据的测定  

Isobaric vapor-liquid equilibria for ethyl acetate-ethanol-ionic liquid ternary systems

作　　者：朱久娟[1] 张继国[1] 李群生[1] 邢风英[1] 

机构地区：[1]北京化工大学化学工程学院,北京100029

出　　处：《北京化工大学学报（自然科学版）》2009年第3期15-19,共5页Journal of Beijing University of Chemical Technology(Natural Science Edition)

摘　　要：在101.32kPa下,用改进的Othmer釜测定了两种乙酸乙酯-乙醇-离子液体三元物系的等压汽液平衡数据,即乙酸乙酯-乙醇-1-丁基-3-甲基咪唑四氟硼酸盐([BMIM]BF4)与乙酸乙酯-乙醇-1-辛基-3-甲基咪唑四氟硼酸盐([OMIM]BF4)。实验结果表明:加入[BMIM]BF4和[OMIM]BF4,汽液平衡线偏离乙酸乙酯-乙醇物系的汽液平衡线;离子液体摩尔分数越大,偏离程度越大;[BMIM]BF4与[OMIM]BF4表现出明显盐效应,使乙酸乙酯对乙醇的相对挥发度发生改变,均消除了乙酸乙酯-乙醇物系的共沸点。离子液体对乙酸乙酯的盐析效应顺序为:[OMIM]BF4>[BMIM]BF4。因此,[BMIM]BF4和[OMIM]BF4可以作为乙酸乙酯-乙醇物系萃取精馏的溶剂,汽液平衡数据的测定可为分离过程优化设计提供依据。Isobaric vapor-liquid equilibrium data for ethyl acetate-ethanol-ionic liquid ternary systems were mea- sured in a modified Othmer still at 101.32 kPa. The ionic liquids employed were 1-butyl-3-methylimidazolium tetrafluoroborate （ [ BMIM ] BF4） and ethyl 1-octyl-3-methylimidazolium tetrafluoroborate （ [ OMIM ] BF4 ）. The vapor-liquid equilibrium curves of the ethyl acetate-ethanol-ionic liquid systems deviate from that of the IL-free system and the deviation increases with increasing amounts of IL. The ILs show a salting-out effect, which increases the volatility of ethyl acetate relative to that of ethanol, and even leads to an elimination of the azeotropic point. The salting-out effect on ethyl acetate decreases in the order： [OMIM]BF4 〉 [BMIM]BF4. As a result, it is concluded that [BMIM]BF4 and [OMIM]BF4 can be used as entrainers for the separation of ethyl acetate and ethanol, and the VLE data obtained here can be used to optimize the process.

关 键 词：汽液相平衡 乙酸乙酯 乙醇 1-丁基-3-甲基咪唑四氟硼酸盐 1-辛基-3-甲基咪唑四氟硼酸盐 

分 类 号：TQ013.1[化学工程]