异丙醇-水-1-辛基-3-甲基四氟硼酸咪唑盐物系等压汽液平衡数据的测定

在101.32 kPa下,用改进的Othmer釜测定了含离子液体1-辛基-3-甲基四氟硼酸咪唑盐([OMIM]BF4)的异丙醇-水物系的等压汽液平衡数据。实验结果表明,加入[OMIM]BF4摩尔分数为10%时异丙醇-水二组分物系的汽液平衡线就开始偏离,[OMIM]BF4摩尔分数分别为20%和30%时,偏离程度越大;[OMIM]BF4表现出盐效应,使异丙醇对水的相对挥发度发生改变,消除了异丙醇-水物系的共沸点;[OMIM]BF4摩尔分数越大,盐效应越明显,随着[OMIM]BF4摩尔分数的增加,异丙醇对水的相对挥发度增加。[OMIM]BF4可以作为异丙醇-水物系萃取精馏的溶剂,适宜的[OMIM]BF4摩尔分数为20%。用NRTL模型对数据进行了关联,关联的结果和实验计算值差不多,符合实验趋势。

Isobaric vapor-liquid equilibrium data for the isopropanol-water-1-octyl-3-methylimidazolium tetrafluoroborate system

Isobaric vapor-liquid equilibrium (VLE) data for the isopropanol-water system containing the ionic liquid (IL) 1-octyl-3-methylimidazolium tetrafluoroborate ([OMIM] BF4) have been measured at 101.32 kPa in a modified Othmer still. The vapor-liquid equilibrium curve for the isopropanol-water system with added IL deviates from the line when the mole fraction of [OMIM] BF4 reaches 10%. When the mole fraction of [OMIM] BF4 reaches 20% or 30%, the deviation from the line increases further. The IL shows a salt effect, which increases the volatility of isopropanol relative to that of water, and even leads to the disappearance of the azeotropic point. As a result,it is concluded that [OMIM] BF4 can be employed as an entrainer for the extractive distillation of the isopropanol-water system. Based on the VLE data, the optimum mole fraction of [OMIM] BF4 is about 20%. The measured ternary data were correlated using the NRTL model, and the correlated result was found to be similar to the experiment data.