Supported choline chloride/urea as a heterogeneous catalyst for chemical fixation of carbon dioxide to cyclic carbonates

In this work, the catalytic efficiency of ionic liquid (IL) choline chloride/urea supported on molecular sieves for the reactions of CO2 and epoxides was studied under different conditions. It was demonstrated that this biodegradable and green catalyst is very active and selective, and choline chloride and urea showed a synergetic effect in promoting these reactions. After reaction, the solid catalyst and the products could be separated easily because the IL was insoluble in the products, and the catalyst was reusable. The origin of the high catalytic efficiency and the reaction mechanism were also discussed.