咪唑类脯氨酸离子液体水溶液体积性质  

Volume Properties of Imidazolium Proline Ionic Liquids Aqueous Solution

作　　者：徐金乔 朱雨航 张少泽 程用熹 彭昌军[1] 刘洪来[1] XU Jin-qiao;ZHU Yu-hang;ZHANG Shao-ze;CHENG Yong-xi;PENG Chang-jun;LIU Hong-lai(School of Chemistry and Molecular Engineering,East China University of Science and Technology,Shanghai 200237,China)

机构地区：[1]华东理工大学化学与分子工程学院,上海200237

出　　处：《华东理工大学学报（自然科学版）》2018年第5期691-698,共8页Journal of East China University of Science and Technology

基　　金：国家自然科学基金(21276073;20476070);国家重点基础研究发展计划(2015CB251401)

摘　　要：在298.15～323.15 K的温度范围内,分别测定了1-丁基-3-甲基咪唑脯氨酸盐[C4mim][L-Pro]、1-己基-3-甲基咪唑脯氨酸盐[C6mim][L-Pro]和1-辛基-3-甲基咪唑脯氨酸盐[C8mim][L-Pro]这3种咪唑类脯氨酸离子液体与水组成的二元混合溶液在全部组成范围内的密度,计算了混合溶液的过量摩尔体积和无限稀释偏摩尔体积,并用相关经验公式进行了拟合。结果表明,混合溶液的密度均随温度的升高而线性减小;当温度和组成一定时,混合溶液的密度随离子液体阳离子上烷基链长度的增加而减小;3种混合溶液的过量摩尔体积均为负值;在相同温度下,3种离子液体和水的无限稀释偏摩尔体积均小于纯离子液体和纯水的摩尔体积,并且下降幅度随离子液体烷基链长度的增加而减小。Densities for three binary mixtures of 1-butyl-3-methylimidazolium proline[C 4mim][L-Pro]、1-hexyl-3-methylimidazolium proline[C 6mim][L-Pro]and 1-octyl-3-methylimidazolium proline[C 8mim][L-Pro]with water were measured at the temperature ranging from 298.15 K to 323.15 K over the entire compositions.The influence of temperature and composition on densities was studied.The excess molar volumes for mixtures and partial molar volumes at infinite dilution for ionic liquids and water were calculated and correlated using empirical equations.The results showed that the densities linearly decreased with temperature,and the relationship between densities and temperature can be correlated precisely using equationρ=α+β(T-273.15).The densities for mixtures decreased with alkyl length of the cation at the same temperature and composition.The excess molar volumes were exclusively negative for these three mixtures because of strong hydrogen bonding and bulk stacking effect between amino acid based ionic liquids and water molecules.The relationship between excess molar volumes and composition can be correlated well using a Redlich-Kister equation.The partial molar volumes at infinite dilution for ionic liquids and water were all lower than molar volumes for pure ionic liquids and water at the same temperature.This is also due to the strong hydrogen bonding between ionic liquids and water.As the alkyl length of the cation increases,the degree of decline decreased for partial molar volumes at infinite dilution compared with molar volumes for ionic liquids and water.The interaction energy between ionic liquids and water were calculated and the results showed that the interaction energy between ionic liquids and water decreased gradually with alkyl length of the cation.

关 键 词：咪唑脯氨酸离子液体 混合溶液 密度 过量体积 

分 类 号：O64[理学—物理化学]