The extensive application of naled compound (1,2-dibromo-2,2-dichloroethyl dimethyl phosphate) for controlling the Zika mosquitoes on South Florida beach area has increased an urgency to address the information gaps with respect to their stabilities and fate in an aqueous environment as these compounds are reported as a potential threat to human health and on the environment. Here, we present the temperature dependent reactivity of naled in neutral aqueous solution. NMR was used to monitor the concentration of naled during hydrolysis. Our results suggested that the rate of hydrolysis in neutral solution pH 6.5 was found slow at ambient temperature. From the pseudo-first order plot of naled hydrolysis at ambient temperature, the rate constant was calculated as 0.002 hr<sup>-1</sup> and half-life is around 15 days.  However, at the elevated temperatures of 40°C-80°C the hydrolysis of naled proceeded faster with a half-life of 2.4 days to 1.5 hrs. The activation energy of naled, calculated from the Arrhenius plot over the range of temperatures 40°C-80°C, was 19.5 kcal mole<sup>-1</sup>. The dimethyl hydrogen phosphate was identified as one of the end products during naled hydrolysis suggesting that the reaction may proceed via the cleavage of phosphorus-oxygen ester bond fission. The pH depended hydrolysis, kinetics and their detail products studies are ongoing.

Hydrolysis of the Zika pesticide naled: Kinetics and mechanistic investigation

255th National Meeting (2018)

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