Photodegradation of buprofezin

Abstract

Buprofezin, a new insecticide cum insect growth regulator, when subjected to UV ‐ photodegra‐dation in methanolic solution (1000 ppm) yielded seven photoproducts which on the basis of Chromatographic and spectroscopic evidences were characterised as (i) N‐tert‐butyl‐N'‐isopropyl thiourea, (ii) N‐ (N‐methyl carbamoyl) ‐N‐isopropyl‐N'‐tert‐butyl thiourea, (iii) N‐phenyl‐N'‐iso‐propyl urea (iv) Phenyl urea (v) isopropyl urea (vi) Phenyl isocyanate and (vii) N‐methyl aniline. In the solid state, buprofezin as a thin film on inert glass surface decomposed rapidly (t1/2 = 32 h) on irradiation with UV‐light (254 mm) . However, under sunlight condition, degradation was comparatively slower (t1/2 = 15 days) . In methanolic solution, the half life in quartz vessel was 4.0 h which on addition of H2O2 (5%) was significantly reduced to 2.25 h.