Abstract: | During UV.-irradiation of aliphatic carboxylic acids and esters in aqueous and nonaqueous solutions various alkyl and acyl type radicals derived from parent compounds and solvents have been observed by ESR.-spectroscopy. The structures of the radicals point to α-cleavage, β-dehalogenation and photoreduction as major photolytic processes of carboxylic acids and esters. The relative contributions of these processes to the overall photodecompositions depend on the carboxyl substituents, on solvent and temperature. Similarities of carboxyl and carbonyl group photochemistry are discussed. |