摘要
合成了同时含有Lewis碱和Brnsted碱的复合碱性离子液体,研究了其在Knoevenagel缩合反应中的催化性能。结果表明,它们对醛/酮与氰乙酸乙酯的缩合具有很好的催化活性,芳香醛的反应收率可达85%～99%。考察了它们催化Knoevenagel缩合反应的溶剂效应,发现质子溶剂可以促进缩合反应,这一促进作用可能是由于质子溶剂通过氢键活化反应底物的羰基而降低了反应能垒所造成的。该离子液体可以循环使用3次,反应活性没有下降。
Lewis-Bronsted combined basic ionic liquids were successfully synthesized. Their catalytic activity for the condensation of aldehydes/ketones with ethyl cyanoacetate was also investigated. The results showed that these combined basic ionic liquids possess very high activity for Knoevenagel condensation. Different aromatic aldehydes reacted with cyanoacetate to give the corresponding products in 85 % - 99 % yields. It was found that protonated solvents had higher activity than other solvents. This solvent effect was probably caused by the activation of carbonyl through hydrogen bond. The combined basic ionic liquids could be reused for 3 times without decrease of activity.
出处
《化学通报》
CAS
CSCD
北大核心
2008年第8期626-630,共5页
Chemistry
基金
国家自然科学基金项目(20533010)资助
