Selectivity of a heterogeneous rhodium catalyst for the carbonylation of monohydric alcohols

Abstract

The carbonylation activity of a heterogeneous rhodium-zeolite catalyst has been examined for the reactions of methanol, ethanol and propan-2-ol. A marked contrast in the behaviour of these three alcohols is seen. Selectivity for the carbonylation of methanol is high (>90 %) at all temperatures, whereas the sole reaction product with propan-2-ol is propene. Ethanol shows intermediate behaviour, exhibiting high selectivity (approaching 100%) for carbonylation at low temperatures, but very poor selectivity at higher temperatures. The results are consistent with the relative ease with which dehydration of the reactants occurs on polar catalysts.