烷基咪唑类离子液体的合成与表征

Synthesis and Characterization of Alkyl Imidazolium-Based Ionic Liquids

采用绿色化学合成法,以N-丁基咪唑和1,2-二甲基咪唑为反应原料,碳酸酯为烷基化试剂,合成了2种离子液体的中间体1-丁基-3-甲基咪唑碳酸甲酯盐([n-BMIM]OCO2Me)和1,2-二甲基-3-乙基咪唑碳酸乙酯盐([EMMIM]OCO2Et),然后通过与HBF4及HPF6的反应,得到产率高、稳定性好的4种离子液体:1-丁基-3-甲基咪唑四氟硼酸盐([n-BMIM]BF4)、1-丁基-3-甲基咪唑六氟磷酸盐([n-BMIM]PF6)、1,2-二甲基-3-乙基咪唑四氟硼酸盐([EMMIM]BF4)和1,2-二甲基-3-乙基咪唑六氟磷酸盐([EMMIM]PF6).产物结构和结晶温度或熔点皆已确认.

The alkyl imidazolium-based ionic liquids,1-n-butyl-3-methylimidazole methyl carbonate（[n-BMIM]OCO2Me） and 1,2-dimethyl-3-ethylimidazole ethyl carbonate（OCO2Et）,were synthesized from N-methylimidazole,1,2-dimethylimidazole and carbonates.Reacting with HBF4 and HPF6 at room temperature,[n-BMIM]OCO2Me and OCO2Et were converted into four ionic liquids： 1-n-butyl-3-methylimidazolium tetrafluoroborate（[n-BMIM]BF4）,1-n-butyl-3-methylimidazolium hexafluorophosphate（[n-BMIM]PF6）,1,2-dimethyl-3-ethylimidazolium tetrafluoroborate（BF4）,and 1,2-dimethyl-3-ethylimidazolium hexafluorophosphate（PF6）.The six ionic liquids were characterized and analysed.Environmental pollution was avoided by the green chemical synthetic method in comparison with the traditional two-step synthesis.