Boosting catalytic performance for CO2 cycloaddition to cyclic carbonates by an imidazolium tetrabromidozincate-modified polystyrene resin

In this study, the [ZnBr4]2- coordination anions, serving as the active component, were successfully immobilized onto chloromethylated polystyrene resin microspheres modified with imidazolium salts, fabricating the heterogeneous catalyst ZnBr4-Imi-CMPS. ZnBr4-Imi-CMPS were characterized by X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS). Under the reaction conditions of 1 MPa CO2, 80 °C, and 3 h, ZnBr4-Imi-CMPS demonstrated excellent catalytic performance in the cycloaddition reaction of CO2 to 1,2-epoxybutane, achieving a conversion rate of 96% with a turnover frequency of 63.3 h-1, which is significantly superior to most of catalysts ever reported. It is anticipated that this heterogeneous catalyst, which obviates the need for solvents and cocatalysts, will offer significant advantages for industrial applications.