KINETICS AND HYDROLYSIS MECHANISM OF TRIASULFURON

The hydrolysis of the sulfonylurea herbicide triasulfuron [(2-(2-chlor oethoxy)-N-[[4-methoxy-6-methyl-1,3,5 -triazin-2-yl) amino] carbonyl]b enzenesulfonamide] was studied in aqueous buffers of pH values 2, 3, 4 , 5, 6, 7, and 9. The reaction was of first-order and pH-dependent. Tr iasulfuron was more persistent in neutral or weakly basic than in acid ic solution. Five metabolites have been isolated and identified. At al l pH values studied, the primary pathway of degradation was the cleava ge of the sulfonylurea bridge. However, minor degradation pathways hav e also been observed like O-demethylation and opening of the triazine ring. The product distribution was pH-dependent.