2-Pyrrolidinecarboxylic Acid Ionic Liquid Catalyzed Knoevenagel Condensation

The pyrrolidinecarboxylic functionalized ionic liquid, 1-butyl-3-methylimidazolium-(S)-2-pyrrolidinecarboxylic acid salt ([bmim][Pro]), was prepared using an improved procedure. α,β-Unsaturated carbonyl compounds were selectively synthesized and high yields (88%–97%) were obtained at room temperature in aqueous media when [bmim][Pro] was used as the catalyst for the Knoevenagel reaction between a methylene compound and an aldehyde or ketone. [bmim][Pro] was reused six times without loss of catalytic activity. The catalytic mechanism is briefly discussed. 改进了 1-丁基-3-甲基咪唑 L-脯氨酸 ([bmim][Pro]) 功能化离子液体的合成路线, 并将该离子液体用于催化含活泼亚甲基化合物与醛或酮的 Knoevenagel 缩合反应. 在水介质中, 室温下, 该离子液体可快速催化上述 Knoevenagel 缩合反应, 并选择性生成 α,β-不饱和羰基化合物且分离收率可达到 88%–97%. 该脯氨酸离子液体循环重复使用 6 次后, 催化活性没有明显的下降. 此外, 初步探讨了其催化过程机理.