Copolymerization of 1,2-Epoxycyclohexane and Carbon Dioxide Using Carbon Dioxide as Both Reactant and Solvent

The copolymerization of 1,2-epoxycyclohexane (cyclohexene oxide, CHO) and carbon dioxide was performed using no other solvent than carbon dioxide itself. A CO2-soluble, ZnO-based catalyst was synthesized and used to catalyze the polymerization. Polymerizations were conducted at different temperatures, pressures, and mole fractions of CHO giving rise to polymer yields as high as 69% with catalyst activities as high as 400 g of polymer/g of Zn. The best results were obtained at temperatures of 100−110 °C and at mole fractions of CHO above XCHO = 0.15. This polymer was >90% polycarbonate with weight average molecular weights (Mw) ranging from 50 000 to 180 000.