Kinetic assessment of relative counterion penetration into cationic micelles: Effects of inert salt on the rate of piperidinolysis of phenyl salicylate in alkaline cationic micellar medium

摘要

Pseudo-first order rate constants for piperidinolysis of ionized phenyl salicylate, obtained at 0.1 M piperidine, constant concentration of CTABr micelles and varying values of [NaOC6H4CO2Na], follow the empirical relationship: k_(obs) =(k0 + θ K~(X/S)[MX])/(1 + K~(X/S)[MX]), where θ and K~(X/S) are empirical constants, MX = NaOC6H4CO2Na and k0 = k_(obs) at [MX] = 0. The values of θ and K~(X/S) are explained in terms of pseudophase micellar model coupled with an empirical relationship: K_S = K_S~0/(1 + .K_(X/S)[MX]), where K_(X/S) is an empirical constant and K_S and K_S~0 are CTABr micellar binding constants of PS" (i.e., S = PS") in the presence and absence of MX, respectively.