Dual-ionic liquid system: an efficient catalyst for chemical fixation of CO2 to cyclic carbonates under mild conditions

Abstract

An easily prepared novel dual-ionic liquid system was developed for cyclic carbonate synthesis from carbon dioxide and epoxides under mild conditions (1 atmos CO₂, T = 30–60 °C) with excellent yields in the absence of any solvents or additives. Moreover, after a simple separation the dual-ionic liquid system could be recycled six times with no loss of catalytic activity. The dual-ionic liquid system contained a functional carboxylate anion, a bromide anion and the N–H bond of the iminium ion, and they had an excellent synergistic catalytic effect on promoting the reactions.