Abstract
Two main steps of photodecomposition were observed at the initial stage on the irradiation of ultraviolet light to Kitazin P® in a thin film. One was the isomerization to a thionate, O-benzyl O, O-diisopropyl phosphorothionate, which was gradually hydrolyzed or oxidized to its oxygen analogue. The other step was the cleavage of P-S bond to produce O, O-diisopropyl phosphonate and α-toluenethiol, the latter of which was degraded to produce α-toluenesul-fonic acid via dibenzyl disulfide, and finally sulfuric acid and benzoic acid. O, O-Diisopropyl hydrogen phosphorothioate, O, O-diisopropyl hydrogen phosphate and benzyl alcohol were detected as hydrolyzates. Benzyl alcohol was further oxidized to benzoic acid via benzaldehyde. In addition to these compounds, O, O, S-triisopropyl phosphorothiolate, O, O, O-triisopropyl phosphorothionate, O, O, O-triisopropyl phosphate and benzyl isopropyl sulfide were also detected.
