Kinetic Study on the Effects of Sodium Benzoate on Piperidinolysis of Phenyl Salicylate in Alkaline Pure Cationic and Mixed Cationic-Nonionic Micelles

Abstract

Pseudo-first-order rate constants (kobs) for piperidinolysis of ionized phenyl salicylate (PS−), obtained at 0.1 M piperidine (Pip), constant concentration of pure CTABr as well as mixed CTABr–C12E23 micelles and varying values of [C6H5CO2Na], follow the empirical relationship: kobs = (k0 + θ KX/S[MX])/(1 + KX/S[MX]) where θ and KX/S are empirical constants, MX = C6H5CO2Na and k0 = kobs at [MX] = 0. The values of θ and KX/S are explained in terms of pseudophase micellar (PM) model coupled with an empirical relationship: where KX/S is an empirical constant as well as KS and are CTABr micellar binding constants of PS− (i.e., S = PS−) in the presence and absence of MX, respectively.