PHOTODEGRATION OF 3-PHENOXYBENZOIC ACID IN WATER AND ON SOLID-SURFACES

3-Phenoxybenzoic acid (I) was irradiated with a xenon lamp (lambda > 290 nm) in buffered aqueous solutions and on the surfaces of Noichi upland soil, kaolinite clay, and silica gel. Hydroxylation at both phenyl rings and ether cleavage were the main photodegradation pathways, and I was finally mineralized to carbon dioxide. Chemical oxidation and O-18 isotopic dilution studies showed that the participation of a hydroxyl radical was of importance in photodegradation of I and that the ether cleavage proceeded via reaction with a hydroxyl radical but via neither photonucleophilic substitution by water molecule nor degradation of 2'-hydroxylated derivative of I.