The pyrolytic reactions of acetaldehyde in presence of nitric oxide

Abstract

Except at very low concentrations where a slight inhibition is observable nitric oxide strongly catalyses the decomposition of acetaldehyde. The rate of the induced reaction is approximately proportional to [aldehyde] 3/2 [NO] ½ . The ratio of nitric oxide consumed to aldehyde decomposed remains small even in conditions where the corresponding ratio for the nitric-oxide-induced ether decomposition approaches unity. The induced decomposition is reduced in rate to a limit by the addition of propylene. From kinetic and analytical measurements it is concluded that the thermal acetaldehyde decomposition occurs partly by a molecular rearrangement mechanism and partly by a radical chain process. The catalysis by nitric oxide involves a chain reaction initiated by hydrogen abstraction, and probably also an acceleration of the molecular process under the influence of collisions with the nitric oxide. The steps of the nitric-oxide-induced chain process are discussed.