Photodegradation of imidacloprid

The photolytic decomposition of the insecticide imidacloprid (1) in HPLC grade water and of imidacloprid as the formulated product Confider insecticide in tap water was studied using HPLC methodology. The structures of several degradates have been determined in aquatic medium, and the DT50 values of imidacloprid and Confider have been measured. In addition, the influence of TiO2 on the photodegradation of Confider was studied. The photoproduct 1-(6-chloro-3-pyridinyl)methyl-2-imidazolidinone (5) has been identified as the main degradate in each of the three series of experiments by several analytical techniques. The photolytic half-lives for imidacloprid under the conditions of this study were 43 min in HPLC grade water, 126 min formulated as Confider in tap water, and 144 min formulated as Confider in tap water in the presence of TiO2.