含离子液体水-醋酸物系等压汽液平衡

Isobaric vapor-liquid equilibria for water-acetic acid system containing ionic liquids at atmospheric pressure

在100 kPa下,用改进的Ellis双循环汽液平衡釜测定了含离子液体三乙基铵醋酸盐([N2,2,2,H][AC])质量分数分别为5%,10%,20%时水-醋酸体系的等压汽液平衡数据,并研究了离子液体对水-醋酸体系汽液平衡的影响。实验结果表明:当水-醋酸体系中[N2,2,2,H][AC]的质量分数为5%时水-醋酸二组分物系的汽液平衡线就开始偏离,但是偏离程度比较小;当[N2,2,2,H][AC]的质量分数增加为10%和20%时,偏离程度增大,[N2,2,2,H][AC]对水-醋酸体系表现出明显的盐效应,使水对醋酸的相对挥发度发生改变;随着离子液体[N2,2,2,H][AC]质量分数增大,水-醋酸体系的盐效应越明显,水对醋酸的相对挥发度也随着增加。[N2,2,2,H][AC]可以做为水-醋酸物系萃取精馏分离的有机盐,所测得的汽液平衡数据可为水-醋酸物系萃取精馏的工艺改进、模拟计算提供热力学基础数据。

At 100 kPa, the isobaric vapor-liquid equilibrium data for the water-acetic acid system containing ionic liquid （IL） triethylammonium acetate （[ N2,2,2,H ] [ AC ] ） were measured in an Ellis still. The vapor-liquid equilibrium curve of the water-acetic acid system began to deviate from the line when the mass fraction of [ Nz,2,2,H [ AC] reached 5%. When the mass fraction of [ N2,2,2,n ] [ AC] was 10% and 20%, the deviation from the line increased. The salt effect of IL changed the relative volatility of water and acetic acid. The more IL was added to the system, the more obvious the salt effect became. The relative volatility of water to acetic acid increased with the increase of IL. It reveals that [ N2,2,2,H ] [ AC ] can be used as an entrainer for extractive distillation of the water- acetic acid system.