吡咯烷酮酸性离子液体中硼酸酯的催化合成

Synthesis of Boric Acid Ester Catalyzed by Pyrrolidonium Acidic Ionic Liquid

研究了硼酸与频哪醇和环己醇在离子液体1-甲基-2-吡咯烷酮硫酸氢盐([Hnmp]HSO4)、1-丁基-3-甲基咪唑四氟硼酸盐([Bmim]BF4)及1-丁基-3-甲基咪唑六氟磷酸盐([Bmim]PF6)中生成2-环己氧基-4,4,5,5-四甲基-1,3,2-二氧硼烷的酯化反应。考察了不同离子液体、反应温度、反应时间和离子液体与反应物物质的量比等对反应的影响。结果表明,当n(硼酸):n(频哪醇):n(环己醇):n([Hnmp]HSO4)=1:1:1:1,反应温度为70℃和反应时间为4h时,硼酸酯的产率为72.5%,离子液体重复使用4次,催化活性无明显降低。

Esterification reaction of boric acid,pinacol and cyclohexanol has been studied in ionic liquids（IL）,including 1-methyl-2-pyrrolidonium hydrogen sulfate（[Hnmp]HSO4）,1-butyl-3-methylimidazolium tetrafluoroborate（[Bmim]BF4） and 1-butyl-3-methylimidazolium hexafluorophosphate（[Bmim]PF6）.The influences of the types of ionic liquids,reaction temperature,reaction time and molar ratio of reactants to IL on the yields of 2-cyclohexyloxy-4,4,5,5-tetramethyl-[1,3,2]dioxaborolan have been investigated.The results showed that under the optimized conditions[n（boric acid）：n（pinacol）：n（cyclohexanol）：n（[Hnmp]HSO4） = 1：1：1：1,70 ℃ and 4 h],the yield of 2-cyclohexyloxy-4,4,5,5-tetramethyl-[1,3,2] dioxaborolan could reach up to 72.5%.The ionic liquid can be used repeatedly for four times without remarkable loss of the catalytic activity.