Self-aggregation of ionic liquids in aqueous media: A thermodynamic study
Self-aggregation of ionic liquids in aqueous media: A thermodynamic study
复制标题
DOI：
10.1016/j.colsurfa.2007.12.043
复制
发表时间：
2008-04
期刊：
影响因子：
--
通讯作者：
Tejwant Singh;Arvind Kumar
中科院分区：
文献类型：
--
作者：
Tejwant Singh;Arvind Kumar
用电导率、密度和声速表征了离子液体1-丁基-3-甲基咪唑四氟硼酸盐[C4mim][BF4]、3-甲基-1-辛基咪唑四氟硼酸盐[C8mim][BF4]、3-甲基-1-辛基咪唑氯[C8mim][Cl]和N-丁基-3-甲基吡啶氯[C4mpy][Cl]在298.15K时的电导率、密度和声速。由实验数据求出了离子液体的临界聚集浓度(CAC)、聚集的标准吉布斯能Δ、∘、等熵压缩性κ和聚集时等熵压缩性的变化Δκ、S、Aggr。研究了ΔGag.∘和ΔκS对阳离子和阴离子性质的依赖关系。根据电导率和压缩系数随浓度变化的质量作用理论，确定了各种离子液体的聚集数n。聚集性质与我们之前报道的核磁共振氢谱和荧光光谱的结果很好地吻合。
Aggregation process of the ionic liquids (ILs), 1-butyl-3-methylimidazolium tetrafluoroborate [C4mim][BF4], 3-methyl-1-octylimidazolium tetrafluoroborate [C8mim][BF4], 3-methyl-1-octylimidazolium chloride [C8mim][Cl], and N-butyl-3-methylpyridinium chloride [C4mpy][Cl], in the aqueous solutions has been characterized by electrical conductivity, density, and speed of sound measurements at 298.15K. The critical aggregation concentration (CAC), the standard Gibbs energy of aggregation ΔGagg.∘, isentropic compressibility κsand changes in the isentropic compressibility upon aggregation Δκs,aggfor the ionic liquids were derived from the experimental data. The dependence of the CAC, ΔGagg.∘, and Δκs,aggon the nature of the cations and anions has been examined. The aggregation number n for various ILs was determined by applying the mass action theory to the concentration dependence of electrical conductivity and compressibility. Aggregation properties showed fairly good agreement with our previously reported results of1H NMR and fluorescence spectroscopy.