Vapor-phase photodecomposition of aldrin and dieldrin.

Abstract

A special reactor was constructed to study the vapor-phase photodecomposition of pesticides by ultraviolet (UV) light. The reactor was designed in such a way that wall reactions would be minimized and could be distinguished from actual vaporphase transformations. The vapor-phase photodecomposition of the insecticides aldrin and dieldrin were studied with this reactor. Irradiation of aldrin vapor with UV light resulted in the formation of photoaldrin and dieldrin. Irradiation of either photoaldrin or dieldrin vapor resulted in a single photoproduct, photodieldrin, which was resistant to further photolysis. Hence, irradiation of aldrin vapor ultimately produced photodieldrin by way of two separate pathways: a photoisomerization followed by photooxidation and a photooxidation followed by photoisomerization.