1-乙基-3-甲基咪唑四氟硼酸盐[Emim]BF4离子液体的制备和表征

Ionic liquids 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim]BF4) were synthesized by the two-steps method. The structure of intermediate product [Emim]Br and ironic liquid[Emim]BF4 were confirmed by UV and IR spectrum. The factors affecting the product yield such as solvent, the ratio of reactants, time of synthesis, temperature have been studied. The optimum synthetic conditions were selected with the orthogonal test and the synthesis mechanism was analyzed. The experiment results showed that the optimal result of synthesis is obtained from reactants at molar ratio1:1.5 with bromoalkane as solvent for about 6 h. The intermediate product [Emim]Br yield is about 95.90%, then equimolar potassium hexafluorophosphate was added and the react time was 10 h under 25 ℃，the yield of ionic liquid [Emim]BF4 is about 97.26%.