Highly efficient solvent-free conversion of CO2 into cyclic carbonates by acrylamide-KI

The cycloaddition of CO2 with epoxide has been a promising way to fix CO2. Developing efficient, low-cost catalysts for this reaction is highly desired. In this paper, we report a novel cocatalyst system that consists of acrylamide and KI for the synthesis of propylene carbonate using CO2 and propylene oxide as starting materials. Different amides (i.e., acrylamide, benzamide, nicotinamide, acetamide, N-isopropylacrylamide, N-tert-butylacrylamide, and N,N-dimethylacrylamide) were combined with different potassium halides to investigate their catalysis capability. KI/acrylamide showed the highest efficiency, and a synergetic effect occurred between acrylamide and KI. At the KI: acrylamide ratio of 1:1 (mol/mol) and concentration of 2.5 mol% for both of them (based on PO), the reaction reached a yield of 95.3%. The catalytic system applies to the cycloaddition reaction using different epoxides. The reaction mechanism was proposed.