Hydrolytic cleavage of paraoxon and parathion by oximate and functionalized oximate ions: A comparative study

Abstract

Bimolecular reactions of O,O-diethyl-O-p-nitrophenylphosphate (paraoxon) and O,O-diethyl-O-p-itrophenyl phosphorothioate (parathion) with oximate (pyridinealdoxime 2-PyOx^- and 4-PyOx^-) and its functionalized oximate, 4-(hydroxyimino)methyl)-1-alkylpyridinium bromide ions (alkyl = C₁₀H₂₁ (4- ₁₀PyOx^-); alkyl = C₁₂H₂₅ (4-C₁₂PyOx^-)) have been investigated in aqueous and cationic micellar media of cetylpyridinium bromide, cetyltrimethyl-ammonium bromide and cetyltetradecyltrimethylammonium bromide at pH 9.5 and 27 ^oC. Under the micellized condition, a 1.2×10³ fold and 9.0×10⁶ fold rate enhancement over the aqueous reaction of paraoxon (k_o = 7.5×10^-8s^-1) and parathion (k_o = 9.5×10^-11) is observed.