Kinetics of the Catalytic Decomposition of Methanol, Formaldehyde and Methyl Formate over a Copper-wire Surface

Abstract

Abstract In order to reveal the selective action of nickel and copper in the catalytic decomposition of methanol, kinetic studies of the decomposition of methanol, and methanol-d1 (CH3OD), and also of that of formaldehyde and methyl formate, both the assumed intermediates of the methanol decomposition, were undertaken over the temperature range between 100 and 330°C and the pressure range up to 30 mmHg. We also made studies of the exchange reaction of methanol, formaldehyde, or methyl formate with deuterium. The obtained rate equation for the methanol decomposition and the results on the deuterium exchange lead to the following conclusion: the rate is controlled by the unimolecular dehydrogenation of adsorbed methanol, which gives formaldehyde at first and finally hydrogen and carbon monoxide via a more stable intermediate, methyl formate. A comparison of activities between copper and nickel was made on the basis of the different behavior of formaldehyde on these catalyst surfaces. The nature of the catalyst surface and of the sites effective for the reaction were also briefly discussed.