Degradation studies of the organophosphorus pesticide, fenitrothion, mediated by cationic surfactants

The thesis describes a kinetic study of the degradation of the pesticide fenitrothion as mediated by cationic surfactants and alpha nucleophilic reagents using UV-visible and 31P NMR spectroscopy.; The reaction of fenitrothion with HO− in the presence of inert counter-ion surfactants was carried out by keeping the total counter-ion concentration constant.; Inert counter-ion salts were found to lower the rate enhancement. The obtention of low k_2m/k_2w values suggests that the rate enhancement is due to the increased concentration of the reactants within the micelles, i.e. a “concentration effect”.; The reaction of fenitrothion with a series of alpha-nucleophile oximates having pK_a in the range of 7.7–11.8 was studied both in the absence and presence of surfactants.; The binding constants, K_S, obtained for fenitrothion in CTA-oximates are variable with different counter-ions, and the rate enhancement depends on the combination of the values of K_S and k_2m.; A Brønsted β_Nu value of 0.21 was obtained for the reaction of fenitrothion with oximates. (Abstract shortened by UMI.)...