Phototransformation of clodinafop-propargyl

Photodegradation of the herbicide clodinafop-propargyl was investigated on glass surface under sunlight and UV light. Four photoproducts were identified by NMR, IR, and MS. Major photolysis products were 2-(5-chloro-3-fluoro-2-pyridyloxy) phenoxy] propanoic acid and prop-2-ynyl-2-(5-chloro-3-hydroxy-2-pyridyloxy) phenoxy] propanoate, while minor were ethyl 2-(5-chloro-3-fluoro-2-pyridyloxy) phenoxy] propanoate and 1-hydroxypropanyl-2-(5-chloro-3-fluoro-2-pyridyloxy) phenoxy] propanoate. Rate of photodegradation followed first-order kinetics with significant correlation coefficient. The major photoproducts were observed in maximum quantity on the 7th and 10th day and further degraded within 15-20 days.