Kinetics of chemical degradation of organophosphorus pesticides; hydrolysis of chlorpyrifos and chlorpyrifos‐methyl in the presence of copper(II)
Kinetics of chemical degradation of organophosphorus pesticides; hydrolysis of chlorpyrifos and chlorpyrifos‐methyl in the presence of copper(II)
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有机磷农药化学降解动力学；铜(II)存在下毒死蜱和甲基毒死蜱的水解
DOI：
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发表时间：
1982
期刊：
影响因子：
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通讯作者：
A. St‐George
中科院分区：
文献类型：
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作者：
P. Blanchet;A. St‐George
测定了在铜(II)存在下，甲基毒死蜱和毒死蜱在缓冲水溶液中的水解反应动力学。对于每个反应，都遵循-d[农药]/dt=K2[农药][Cu2+]的速率定律。随着铜(II)浓度的增加，水解率相应增加，直至铜(II)浓度达到约1×10−·2M。在这一点上，水解率变得与两个反应中铜(II)的浓度无关。根据实验数据，提出了铜(II)离子与环结构中的氮和硫代硫酸盐部分的硫形成六元环络合物的反应机理。PH值越高，水解率越高。在较高的pH值下，观察到Cu2+的析出，一般的碱解反应变得越来越重要。用烷基的诱导效应理论解释了观察到的速率常数的差异。
The kinetics of the hydrolysis reactions of chlorpyrifos-methyl and chlorpyrifos, in the presence of copper(II), have been measured in buffered aqueous solutions. For each reaction, a rate law of the type -d[pesticides]/dt= k2[pesticides][Cu2+] was observed. As the concentration of copper(II) increased, a corresponding increase in the rate of hydrolysis was observed until the concentration of copper(II) reached about 1.0 × 10−2M. At this point, the rate of hydrolysis became independent of the concentration of copper(II) in both reactions. Using the experimental data, a mechanism for each reaction is proposed, in which the copper(II) ion forms a six-membered ring complex with the nitrogen in the ring structure and the sulphur of the phosphorothioate moiety. The rate of hydrolysis increased with increasing pH. At higher pH values, precipitation of Cu2+ was observed and general base-hydrolysis reactions became more and more important. The differences in the rate constant observed is explained using the inductive effect theory of the alkyl group.