高纯4,5-二氰基-2-三氟甲基咪唑锂的制备与性能研究

Study on preparation and properties of high⁃purity lithium 2-trifluoromethyl-4,5-dicyanoimidazole

以4,5-二氰基-2-三氟甲基咪唑(TDI)和无水氯化锂为原料,制备高纯4,5-二氰基-2-三氟甲基咪唑锂(LiTDI)。考察了原料物质的量比、反应温度和反应时间对粗品收率的影响,以及重结晶溶剂、溶剂用量、降温速率、重结晶时间对产品纯度和收率的影响。实验结果表明:在m(DMC)/m(TDI)=2、n(LiCl)/n(TDI)=1、反应温度为45℃、反应时间为5 h条件下,反应液经过滤-浓缩-降温结晶后,粗品收率可达78%;在重结晶溶剂为乙二醇二甲醚、m(乙二醇二甲醚)/m(LiTDI粗品)=2、降温速率为3℃/h、结晶时间为10 h条件下,制得的LiTDI纯度≥99.95%、收率可达88%。此外,LiTDI作为锂离子电池添加剂,可以显著提升锂电池的常温和高温循环性能。

Lithium 2-trifluoromethyl-4,5-dicyanoimidazole(LiTDI)with high purity was synthesized by the raw materials of 2-trifluoromethyl-4,5-dicyanoimidazole(TDI)and lithium chloride.The effects of volume ratio of reactants,reaction temperature,reaction time on the crude product yield were investigated,and the effects of recrystallization solvent,amount of solvent,cooling rate,recrystallization time on the product purity and yield were studied.The experimental results showed that after filtration-concentration-cooling crystallization of the reaction liquid,the crude product yield was 78%at m(DMC)/m(TDI)=2,n(LiCl)/n(TDI)=1,reaction temperature of 45℃,reaction time of 5 h,and the product purity was greater than or equal to 99.95%and the yield was 88%,when the recrystallization solvent was dimethoxyethane,m(dimethoxyethane)/m(crude LiTDI)=2,the cooling rate was 3℃/h,the recrystallization time was 10 h.In addition,adding LiTDI in electrolyte could significantly improve the performance of battery at room temperature and high temperature.