Your Current Location is:Home > Data Resource > Articles

Ionic Liquids Articles

★ Articles list

File name
File size
Download path
Pechmann Reaction in Non-Chloroaluminate Acidic Ionic Liquids under Solvent-Free Conditions
顾彦龙 / 邓友全
81.32 KB

Four non-chloroaluminate acidic ionic liquids have been used as catalysts for Pechmann condensations of phenols under solvent-free conditions. SO3H-functionalized trifluoromethanesulfonate imidazolium ionic liquid has proved to be the most active catalyst. Ionic liquid loads as low as 5 mol % can be used leading to high yields with activated phenols at an oil bath temperature of 80 degrees C. The acidities of the four ionic liquids have also been tested using the Hammett method in dichloromethane. The results are consistent with their catalytic activities as observed in the Pechmann reaction of resorcinol. This methodology offers significant improvements for the synthesis of coumarins with regard to yield of products, simplicity in operation, and green aspects by avoiding toxic catalysts and solvents.

★★★☆☆ Keywords: acid catalysis; coumarins; determination of acidity; ionic liquids; Pechmann condensation

★★★☆☆ Adv. Synth. Catal. 2005, 347, 512– 516.