Stabilization of the pesticide Fenitrothion toward O and N nucleophiles in the presence of cyclodextrins

Abstract

The reaction of Fenitrothion with O and N nucleophiles (H2O2, NH2OH, n-butylamine and piperidine) was studied at 25 °C in water containing 2% 1,4-dioxane in the presence of native cyclodextrins (α-, β-, and γ-CD). For all the nucleophiles, the presence of CD produces reaction inhibition with saturation kinetics. The greatest effect in all cases is observed with β-CD, and the greatest inhibition was observed for the reaction of Fenitrothion with H2O2 (81%), which is the most efficient nucleophile in promoting Fenitrothion degradation in homogeneous media. In the absence of CD, competition between the SN2(P) and the SN2(C) pathways was observed with piperidine as was reported before for the reaction with NH2OH and n-butylamine. The presence of β-CD does not modify product distribution in the case of the reaction with NH2OH and n-butylamine, whereas there is an increase in SN2(C) pathway when the nucleophile is piperidine.