Photolytic oxidation of aliphatic acids by aqueous sodium hypochlorite

Abstract

Photolytic oxidation of acetic and propionic acids by aqueous sodium hypochlorite has been studied. In the presence of excess of sodium hypochlorite, these acids were photo-oxidised effectively to CO₂ and H₂O, but the reaction did not occur in the dark. By contrast, irradiation of an equimolar mixture of propionic acid and sodium hypochlorite gave the oxygenated products CH₃CH(OH)CO₂H, HOCH₂CH₂CO₂H, CH₂(CO₂H)₂, CH₃COCO₂H, CH₃CO₂H, HOCH₂CO₂H, and CO₂ together with small amounts of the chlorinated products CH₃CHClCO₂H, ClCH₂CH₂CO₂H, and ClCH₂CO₂H. The chlorination products were favoured at lower wavelength (e.g. >300 nm). Secondary photo-oxidation of these products was also studied and the reactivities are discussed.