Peroxomonophosphoric acid oxidations: kinetics and mechanism of oxidation of aliphatic aldehydes

Abstract

The peroxomonophosphoric acid (PMPA) oxidation of six aliphatic aldehydes has been studied in the pH range 0–13. The reactions are second order, first order each in [aldehyde] and [PMPA] at constant pH. In alkaline medium the stoicheiometric ratio of PMPA to aldehyde is 1.0. In acid medium the ratio is significantly higher (1.5) pointing to the fact that an oxidation reaction and a carbonyl-assisted decomposition of PMPA occur simultaneously through a common intermediate. The pH–rate dependence was complex. A suitable rate law in a limited pH range 0–3 has been derived.