First Photocatalytic Synthesis of Cyclic Carbonates from CO2 and Epoxides Using CoPc/TiO2 Hybrid under Mild Conditions

First report on the photocatalytic coupling of carbon dioxide with epoxides to give cyclic carbonates under extremely mild conditions such as room temperature and atmospheric pressure conditions using a hybrid photocatalyst consisting of cobalt phthalocyanine grafted on titanium oxide (CoPc/TiO2) under visible irradiation is described. The developed protocol provided almost quantitative conversion of various epoxides to corresponding cyclic carbonates in excellent yields without any evidence for the formation of any byproduct. At the end of the reaction, the photocatalyst was separated by centrifugation and reused for several subsequent recycling runs without any significant loss in activity, and no leaching had been observed during the photocatalytic reactions.