Understand the Molecular Orbital Theory on the Hydrolytic Reactivity of Herbicide Flumioxazine

Hydrolytic reactivities of N-phenylphthalimid herbicide flumioxazine (S) were disccused using molecular orbital (MO) theoretical method. It is revealed that below pH 5.0, the protonation to carbonyl oxygens atom of 1,2-dicarboximino group by general acid catalysis with hydronium ion proceeds via charge controled reaction. Whereas, the specific base catalysis with hydroxide anion via orbital controled reaction occurs above pH 8.0. We may concluded that in the range of pH , the hydrolysis proceeds through nucleophilic addition elimination reaction, these two reactions occur competitively.