咪唑型离子液体热物理性质测量

利用自行搭建的热线法液体热导率和热扩散系数装置测试了两种咪唑型离子液体(C6m Im]BF4]和C4m Im]BF4])在不同温度下的热导率和热扩散系数。根据文献报道的密度数据获得了样品的比热容。结果表明:两种离子液体的热导率与温度的相关性不大;两种阳离子结构相似的离子液体热扩散率相近,热扩散率随温度的升高有明显的变化,本文认为离子液体内部的离子动量分布与温度紧密相关,离子间的动量交换随温度的升高而增加,离子动量分布随温度升高逐渐趋于一致,离子间碰撞产生的动量交换不再明显改变离子的动量,导致热扩散率的变化随温度升高而减小。

Thermo-physical properties measurement of imidazolium ionic liquids

Thermal conductivity and diffusivity of two imidazolium ionic liquids(C₆mIm]BF₄] and C₄mIm]BF₄]) were measured by self-built hot wire method instrument. Heat capacity was calculated according to an equation of thermal conductivity, thermal diffusivity and density. The results show that the thermal conductivities of two ionic liquids have weak relation with temperature. Thermal diffusivities of two ionic liquids are very close. Thermal diffusivity changes with the increasing temperature noticeably. According to the analysis of the change of diffusivity in the micro-perspective mechanism, the momentum distribution of ions in ionic liquids has strong relation with temperature and thus affects the change of diffusivity.