Highly recyclable polymer supported ionic liquids as efficient heterogeneous catalysts for batch and flow conversion of CO2 to cyclic carbonates

Abstract

A series of cross-linked polymer supported ionic liquids based on quaternary ammonium salts have been prepared using a facile method of radical polymerization. Styrene-functionalized quaternary ammonium chloride salts, which are derived from imidazole, trimethylamine, triethylamine and triethanolamine, were copolymerized with divinyl benzene (DVB) under solvothermal conditions. These polymer supported ionic liquids displayed high efficiency in catalytic conversion of CO₂ to cyclic carbonates. Notably, to the best of our knowledge, it was the first time that the polymeric ionic liquid catalyst was applied in a continuous flow fixed-bed reactor. During the study period of 130 hours, the polymer supported ionic liquids exhibited high stability.