Efficient synthesis of cyclic carbonates from CO₂under ambient conditions over Zn(betaine)₂Br₂: Experimental and theoretical studies

It is very interesting to synthesize high value-added chemicals from CO2 under mild conditions with low energy consumption. Here, we report that a novel catalyst, Zn(betaine)2Br2, can efficiently promote the cycloaddition of CO2 with epoxides to synthesize cyclic carbonates under ambient conditions (30 °C, 1 atm). DFT calculations provide important insights into the mechanism, particularly the unusual synergistic catalytic action of Zn2+, Br- and NR4+, which is the critical factor for the outstanding performance of Zn(betaine)2Br2. The unique features of the catalyst are that it is cheap, green and very easy to prepare.