Dependence of transformation rate

The dependence of transformation rate on pH is not always consistent among pesticides within the same chemical class. For example, while the hydrolysis reactions of most OP (Konrad and Chesters, 1969 Konrad et al., 1969 Mabey and Mill, 1978) and carbamate insecticides (Wolfe et al., 1978) are primarily base-catalyzed, both diazinon (Konrad et al., 1967) and carbosulfan (Wei et al., 2000) are also subject to the acid-catalyzed reaction. Summaries of the pH dependence of hydrolysis rates for a variety of pesticides have been provided by Mabey and Mill (1978), Bollag (1982), Schwarzenbach et al. (1993), and Barb ash and Resek (1996). 

The temperature dependencies of both nucleation of a new phase and its rate of growth result in a strong temperature dependence of transformation rate. 

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