Abstract: Polymer-supported quaternary phosphonium salts were explored to catalyze the cycloaddition of CO₂ and epoxides. The results indicated that this heterogeneous catalyst possessed high activity and selectivity in the cycloaddition reaction. The catalyst was characterized by thermogravimetric analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy. The influence of CO₂ pressure, reaction temperature, reaction time, and catalyst amount on the cycloaddition reaction was investigated. Excellent yield (97.7%) and high selectivity (> 99%) of cyclic carbonates were achieved under the conditions of p(CO₂) = 4.5 MPa, 150 ^oC, 6 h, and catalyst 0.09 g. The catalyst could be recovered easily and reused several times. A possible reaction mechanism for the cycloaddition of CO₂ and epoxide to cyclic carbonate over the polymer-supported quaternary phosphonium salt was discussed.

Key words: polymer, quaternary phosphonium salt, carbon dioxide, epoxide, cycloaddition, cyclic carbonate