The effect of structure of alkylammonium halides on the outcome of cycloaddition of carbon dioxide to oxiranes was studied. The conversion of epichlorohydrin to chloromethylethylene carbonate depends nonlinearly on the length of the hydrocarbon chain in the alkylammonium halide catalyst. Tetraethylammonium and benzyltriethylammonium were the most effective cations in the catalyst used. Acetone was the solvent of choice for this reaction under the studied conditions.