Reaction of chlorpyrifos-methyl in aqueous hydrogen sulfide/bisulfide solutions
Reaction of chlorpyrifos-methyl in aqueous hydrogen sulfide/bisulfide solutions
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DOI：
10.1021/jf020955w
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发表时间：
2003-03-26
影响因子：
6.1
通讯作者：
Miah, MH
中科院分区：
文献类型：
--
作者：
Jans, U;Miah, MH
测定了有机磷杀虫剂甲基毒死蜱与硫化氢(H_2S)和二硫化氢(HS-)在水溶液中的反应动力学。甲基毒死蜱与二硫化物的拟一级反应速率常数为(2.1+/-0.3)x 10(-3)M-1 S(-1)。甲基毒死蜱与硫化氢的二级速率常数明显慢于与二硫化氢的二级速率常数。当H_2S浓度达到4 mM时，H_2S对观察到的甲基毒死蜱降解速率常数的贡献不大。甲基毒死蜱与H_2S的二级反应速率常数太低，无法测定。结果表明，环境相关浓度的HS-可能是沿海海洋环境中硫代磷酸三酯的重要汇，而H2S的反应太慢，不能与环境相关(pH 6-9)。甲基毒死螨水解的主要产物三氯吡啶是甲基毒死蜱与二硫化物反应的次要产物，但在本实验条件下，三氯吡啶是稳定的。
The kinetics of the reactions of chlorpyrifos-methyl, an organophosphorus insecticide, with hydrogen sulfide (H2S) and bisulfide (HS-) were determined in well-defined aqueous solutions. The resulting pseudo-first-order rate constant for chlorpyrifos-methyl with bisulfide yielded a second-order rate constant of (2.1 +/- 0.3) x 10(-3) M-1 s(-1). The second-order rate constant for chlorpyrifos-methyl with hydrogen sulfide is significantly slower than the second-order rate constant with bisulfide. The contribution of H2S to the observed degradation rate constant of chlorpyrifos-methyl at concentrations of up to 4 mM H2S is not significant. The second-order rate constant of chlorpyrifos-methyl with H2S was too low to be measured in this study. The results indicate that HS- present at environmentally relevant concentrations may represent an important sink for phosphorothionate triesters in a coastal marine environment, while H2S reacts too slowly to be environmentally relevant (pH 6-9). Trichloropyridinol, the major product of hydrolysis of chlorpyrifos-methyl, is only a minor product of the reaction of chlorpyrifos-methyl with bisulfide; however, trichloropyridinol was found to be stable under the experimental conditions.