1-丁基-3-甲基咪唑四氟硼酸盐的热稳定性、平衡蒸汽压和标准蒸发焓

利用非等温、等温热重分析(TG)法,研究了高纯氮气气氛下1-丁基-3-甲基咪唑四氟硼酸盐([bmim][BF4])离子液体的热稳定性、平衡蒸汽压和标准蒸发焓.非等温热重(TG)曲线表明[bmim][BF4]的初始分解温度(Tonset)和最大分解速率对应的温度(Tm)分别为697和734K.然而长期等温TGA研究表明,[bmim][BF4]的最高可使用温度约为513K.另外,利用基于TG的蒸发技术研究了[bmim][BF4]的平衡蒸汽压(pe)与温度的关系并计算了标准蒸发焓.在503-543K温度范围内,离子液体[bmim][BF4]的pe和温度的关系是:lgpe=(16±1)+(-6.85±0.25)×103/T.[bmim][BF4]的标准蒸发焓为(131±5)kJ·mol-1.

Thermal Stability,Equilibrium Vapor Pressure and Standard Enthalpy of Vaporization of 1-Butyl-3-methylimidazolium Tetrafluoroborate

The thermal stability, equilibrium vapor pressure, and standard enthalpy of vaporization of 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) ion liquid were investigated using both non-isothermal and isothermal thermogravimetric analysis (TGA) under high purity nitrogen as a carrier gas. The non-isothermal thermogravimetric (TG) curve showed that the onset and peak decomposition temperatures were 697 and 734 K, respectively. However, long-term isothermal TGA studies revealed that the highest application temperature for [bmim][BF4] was 513 K. Moreover, the temperature dependence of the equilibrium vapor pressure and the standard enthalpy of vaporization of [bmim][BF4] were also investigated by TG-based transpiration. In the temperature range of 503-543 K, the relationship between the equilibrium vapor pressure (pe) of [bmim][BF4] and temperature was lgpe=(16±1)+(-6.85±0.25)×103/T. The standard enthalpy of vaporization (△vapHΘ) of [bmim][BF4] was found to be (131±5) kJ·mol-1.