Abstract: A catalyst system of ZnBr2-quaternary onium tribromide salt has been developed for the coupling reaction of carbon dioxide and epoxides. The effects of metal salts and reaction conditions and the recyclability of the catalysts were investigated. The results demonstrated that the coupling reaction of CO2 and epoxides to form cyclic carbonates with high yield proceeds very effectively at 413 K under 1.0 MPa by using ZnBr2 in conjunction with the phenyltrimethylammonium tribromide co-catalyst without solvent.

Key words: zinc bromide, quaternary onium tribromide salt, epoxide, carbon dioxide, coupling reaction, cyclic carbonate