Parathion was once a commonly used pesticide that acts as an acetylcholinesterase inhibitor making it toxic to humans. Further, it can metabolize to paraoxon, a molecule that is even more toxic. It is very stable, immobile in soil, and can be washed into waterways. Previous work has indicated that the pH of the environment has an impact on the hydrolysis rates of Parathion. We explored this phenomena using density functional theory. Our work looks at the degradation mechanism of parathion into paraoxon and 4-nitrophenol at the atomistic level, as well as paraoxon degradation to 4-nitrophenol. Two levels of basicity were explored to elucidate the impact of the underlying alkaline environment. Explicit water molecules were included to determine if a pentacoordinate intermediate would form – a hotly debated aspect in the computational literature. Our work is in-line with previous experimental work and gives atomistic insight into the hydrolysis mechanism.

Parathion and paraoxon hydrolysis with increasing basicity: A density functional theory study

Where thousands of chemistry professionals meet to share ideas and advance scientific and technical knowledge. Spring 2023 abstracts, posters, and presentations will launch at the end of March.

ACS Spring 2023

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.