Selective formation of chloroethane by the hydrochlorination of ethene using zinc catalysts

A detailed study of the hydrochlorination of ethene and higher alkenes using ZnCl2/SiO2 and ZnCl2/Al2O3 catalysts is described and discussed. Based on earlier observations that supported gold can be an active catalyst for both ethyne hydrochlorination and oxidation reactions, we initially investigated using supported gold as catalysts for the oxychlorination of ethene. However, we found that oxychlorination did not occur in the presence of oxygen and, furthermore, that the gold acted as a poison/inhibitor during the initial reaction period, with the underlying reaction being ethene hydrochlorination. Supported Zn2+ was found to be a very effective catalyst for this reaction. The hydrochlorination of higher alkenes occurred, with high selectivity to a range of relatively complex chlorinated hydrocarbon products at rates of ca. 10–13 mol/(kgcat h).