Polystyrene-supported Novel Imidazolium Ionic Liquids: Highly Efficient Catalyst for the Fixation of Carbon Dioxide under Atmospheric Pressure

A novel polystyrene-supported ionic liquid (PS-IMPCOOHTMGBr) is synthesized and successfully applied to catalyze the cycloaddition of CO2 and epichlorohydrin (ECH). The 97.2% product yield is achieved at 80 degrees C under atmospheric pressure. The high activity is attributed to the ability of CO2 capture and multiple active centers of immobilized imidazolium ionic liquids. The catalytic activity is enhanced with the increasing amount of immobilized ionic liquids. Even after 9 runs, there is no obvious decrease for the catalytic activity of PSIMPCOOHTMGBr. To further elucidate the catalyst structure and its catalytic feature, the PS-IMPCOOHTMGBr is characterized by elemental analysis, thermal gravimetric analysis, infrared spectroscopy, scanning electron microscopes, solid state NMR, and Brunauer-Emmett-Teller analysis. Two possible reaction mechanisms are proposed according to the characterized results and reported literature. The ionic liquids supported on the PS would have the comparable catalytic activity with those immobilized on the porous materials by judicious choice of ionic liquids.