GC MS ANALYSIS OF PHOTODEGRADATION PRODUCTS OF DICHLOPHOP-METHYL

The photochemical transformation products of 2-[4-(2,4-dichlorphenoxyphenylen]propionic acid methyl ester (I), the active ingredient of the herbicide Dichlophop methyl (trade mark Illoxane) after irradiation with Hg (lambda(max)=254 nm) and Xe (lambda>290 nm) lamps in solution, in thin film on the glass surface and in soil were studied by GC-MS. The main photodegradation pathway was found to be reductive and oxidative dechlorination, intramolecular cyclisation and ester bonds cleavage. The photodegradation of Illoxane is considered as a model for chlorophenoxy pesticides degradation and toxic methabolites formation in the environment.