Chemical fixation of carbon dioxide with epoxides to form cyclic carbonates proceeds very effectively under mild conditions by using a chitosan-supported zinc chloride catalyst in conjunction with 1-butyl-3-methylimidazole halides (BMImX) without any organic solvents. Reaction temperature, carbon dioxide pressure, effects of co-catalysts and the molar ratio of catalyst to co-catalyst were investigated. The optimum reaction conditions were 110degreesC and 1.5 MPa. and BMImBr was the best co-catalyst. The catalyst system was recycled and reused. (C) 2004 Elsevier B.V. All rights reserved.