Photoinduced oxidation of benzoic acid with aqueous hydrogen peroxide

Abstract

The photodecomposition of benzoic acid in aqueous hydrogen peroxide has been studied. When the ratio [H₂O₂]₀/[PhCO₂H]₀ is low, the decomposition of benzoic acid and hydrogen peroxide stops during irradiation, while at a high [H₂O₂]₀/[PhCO₂H]₀ ratio, benzoic acid is completely decomposed with cleavage of the aromatic ring. Hydroxybenzoic acid is a major product, and benzene and phenol are minor products during the initial stages of oxidation. Later lower aliphatic acids such as malonic acid appear. The probable mechanism for decomposition is discussed on the basis of product yields.