| Abstract: | In order to study the photoreactivity and possible photodegradation pathways of ethiofencarb (2-ethylthiomethylphenyl methylcarbamate) on plant surfaces, model experiments in the presence of cyclohexane, cyclohexene methylcarbamate)onand iso-propanol were performed. Both artificial light (λ > 280 nm) and natural sunlight were used. Half-lives of the ethiofencarb photodegradation were in the order cyclohexane < isopropanol < cyclohexene and ranged from 75 min to more than 20 h. Depending on the solvent and the light source chosen, different photo-products were obtained. When ethiofencarb was irradiated in the presence of cyclohexane, photo-oxidation to the corresponding sulfoxide was the main degradation pathway, followed by a cyclization reaction. In the case of isopropanol as model solvent, numerous photoproducts were detected as a result of photo-oxidation, hydrolysis and the addition to ethiofencarb of the solvent molecule. |
