Cyclic carbonate formation from cycloaddition of CO₂ to epoxides over bismuth subgallate photocatalyst

One of the lucrative means of CO₂ fixation is the chemical transformation of CO₂ and epoxides into cyclic carbonates. In this regard, we report the photocatalytic synthesis of several cyclic carbonates using cycloaddition of CO₂ to epoxides catalyzed by a bismuth subgallate coordination polymer photocatalyst, (Bi-gallate), under mild reaction conditions. Bi-gallate photocatalyst was characterized using various analytical and spectroscopic techniques including powder X-ray diffraction (PXRD), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) analyses, nitrogen sorption measurements, and thermogravimetric analysis (TGA). The photocatalytic cycloaddition quantitatively converted various epoxides to corresponding cyclic carbonates in moderate to high conversions. Moreover, the photocatalyst could catalyze the cyclization reactions in three consecutive cycles without any loss of photocatalytic activity.