MICELLAR EFFECTS OF SURFACTANTS IN CLEAVAGE OF 4-NITRO-PHENYL DIETHYL PHOSPHONATE BY HYDROPEROXIDE ANION

We have studied the nucleophilicity of the hydroperoxide anion relative to 4-nitrophenyl diethyl phosphonate (NPDEPS) in the presence of cetyltrimethylammonium bromide (water, 25 °C) while varying the acidity of the medium and the hydroperoxide anion concentration over a broad range. The increase in the reaction rate when the reaction is transferred to a micellar pseudophase is as high as ~10-fold, which is explained by concentration effects. In CTAB micelles, as in water, the hydroperoxide ion is one of the most effective alpha-nucleophiles, and the size of the alpha-effect, characterized by the ratio of the second-order rate constants for reactions of HOO– and OH– anions with NPDEPS, remains practically constant and reaches a value of ~50-fold.