铝基离子液体BMIAlCl_4的热力学性质

Thermodynamic Properties of Ionic Liquid BMIAlCl_4

在高纯氩气氛下,直接将摩尔比为1:1的高纯无水AlCl3和BMIC(氯化1-甲基-3-丁基咪唑)搅拌混合,得到一种无色透明的离子液体BMIAlCl4.在278.2～343.2K范围内,用最大气泡法测定了BMIAlCl4的表面张力,用Westphal天平法测定了该离子液体的密度;利用Glasser经验方程讨论了该离子液体的热力学性质,并与其它离子液体作了比较.根据空隙模型计算了BMIAlCl4离子液体的恒压热膨胀系数,与本文实验值基本一致,说明空隙模型具有一定的合理性.

An ionic liquid （IL） has been prepared by directly mixing AlCl3 and 1-methyl-3-butylimidazolium chloride （BMIC） with molar ratio 1/1 under dry argon atmosphere. The densities and surface tensions of the pure IL were determined in the temperature range of （278.2±0.1） to （343.2±0.1） IC The properties for the ionic liquid were discussed in terms of Glasser＇s empirical model. The values of volume of anion AlCl4^- were obtained. The mean contribution of per methylene（CH2） group to standard entropy of the IL is 35.2 J·K^-1·mol^-1 and is in good agreement with＇contribution of 35.1 J· K^-1·mol^-1 from [Cn-min] [NTf2]. The crystal energy of the IL is much lower than that of ionic solids, which is the main reason for the liquid state of the IL at room temperature. In addition, the interstice model was applied to calculate the thermal expansion coefficient of the IL, and the result agrees reasonably with the experimental value.