The oxidation of acetylene

Abstract

The oxidation of acetylene at temperatures between 300 and 400 °C has been studied both manometrically and by detailed product analysis. The results of previous investigators have in general been confirmed but in addition important new kinetic data have been established. In particular, experiments involving the addition of glyoxal and formaldehyde to the reaction mixture have shown that glyoxal has the characteristics of a degenerate branching intermediate while the effect of the addition of formaldehyde is complex and depends on the nature of the surface. In addition to the products previously identified, namely, carbon monoxide, carbon dioxide, water, hydrogen, glyoxal, formaldehyde, formic acid and acetaldehyde, we have shown that reaction between acetylene and oxygen can give rise to traces of acrolein, glyoxalic acid, oxalic acid and hydrogen peroxide. The consumption of acetylene has been shown to involve two major reactions representing the two modes of attack of the proposed main chain carrier, OH, on the molecule, namely abstraction and addition. To a first approximation, however, the abstraction reaction can be ignored and the course of the oxidation of acetylene can be successfully described by a degenerately branched chain reaction with glyoxal as the most important branching agent.