Visible light assisted chemical fixation of atmospheric CO2 into cyclic Carbonates using covalent organic framework as a potential photocatalyst

Abstract

We have demonstrated the photo-catalytic fixation of CO2 over epoxides for the formation of corresponding cyclic carbonates using a mesoporous Covalent Organic Framework (COF) which acts as a potential photocatalyst with TBAB (Tetrabutyl ammonium bromide), 5 mol% as the co-catalyst under atmospheric pressure in visible light. Greater than 86% yield of the isolated product is achieved with the use of 5 mg of catalyst. The use of Catalyst and co-catalyst TBAB controls the reaction cycle. There is no progress of the reaction occurred in the absence of light (445 nm) even on the elevation of reaction temperature. We have also demonstrated that 25% of the isolated product could be obtained with the use of sunlight using the catalytic cycle. These results open the door to an entirely new class of protocol for photo catalytically fixation of CO2 into cyclic carbonate from epoxide using COF as photocatalyst under visible light.