磺酰脲除草剂单嘧磺隆水解和水中光解研究

Hydrolysis and Photolysis of Sulfonylurea Herbicide Monosulfuron in Water

实验室条件下,利用高效液相色谱研究了单嘧磺隆水解和水中光解动态特性。结果表明,25℃时单嘧磺隆在pH 5、pH 7和pH 9缓冲溶液中的水解半衰期分别为42.5 d、248 d和19.7 h,50℃时则分别为32.8 h、117 h和12.5 h,水解速率随温度升高而升高,温度效应系数为1.58～50.9。单嘧磺隆在碱性缓冲溶液中水解最快,在中性条件下水解最慢,pH 9缓冲溶液的水解活化能和活化熵最小。在本研究试验条件下,单嘧磺隆在水中光解半衰期为45.3 h。

The hydrolysis and photolysis of monosulfuron in water were investigated with high performance liquid chromatography in laboratory conditions.The results showed that the hydrolysis half-lives of monosulfuron were 42.5 d,248 d and 19.7 h in pH 5,pH 7 and pH 9 buffer solutions at 25℃,respectively.At 50℃,the levels of hydrolysis of monosulfuron were 32.8 h,117 h and 12.5 h in three different buffer solutions correspondingly.The hydrolytic rate of monosulfuron increased with the temperature increasing and the temperature coefficients were 1.58-50.9.The hydrolysis of monosulfuron was the most rapid in alkali buffer solution and the most tardy under neutral condition.The smallest values of activation energy and activation entropy were obtained from hydrolysis in pH 9 buffer solution.The photolysis half-life of monosulfuron was 45.3 h under the test condition.