The hydrogenation of CO over molybdenum/alumina in the presence of ethylene; coupling of olefin metathesis and CO hydrogenation

Abstract

Three reactions, CO hydrogenation, metathesis of C2H4 and CO hydrogenation in the presence of C2H4, have been investigated on Mo(+2)/Al2O3 under identical experimental conditions. The products of hydrogenation reactions were methane, ethylene and propylene. The results show that the initial rate of propylene formation for CO hydrogenation in the presence of ethylene is much larger, by a factor of 7, than the sum of the rate of propylene formation for CO hydrogenation and metathesis alone. Furthermore, it was found that13C labelled propylene was formed in the hydrogenation of13CO in the presence of ethylene. These results, taken as a whole, suggest that the same intermediate is formed in both CO hydrogenation and metathesis of ethylene, and that these intermediates can be either incorporated into ethylene and higher hydrocarbons by polymerization or incorporated into ethylene to form propylene via olefin metathesis.