An empirical approach to study the occurrence of ion exchange in the ionic micellar‐mediated semi‐ionic reactions: Kinetics of the rate of reaction of piperidine with ionized phenyl salicylate in the presence of cationic micelles

Pseudo‐first‐order rate constants (k_obs)—obtained for the cleavage of ionized phenyl salicylate (PS^?) at constant [NaOH], [MeCN], [CTAZ]_T (total concentration of cetyltrimethylammonium chloride and bromide), [Pip]_T (total concentration of piperidine), and varying concentrations of sodium cinnamate, acetate, and butanoate ([NaX])—follow the relationship: k_obs = (k₀ + θ K[NaX])/(1 + K[NaX]), where θ and K are empirical parameters. The values of θ are almost independent of [CTAZ]_T, while K values decrease with the increase in [CTAZ]_T within its range 0.006–0.020 M. The values of θ and K are explained in terms of pseudophase model of micelle coupled with an empirical relationship: K_S = K_S⁰/(1 + Ψ_X/S [NaX]), where K_S is the CTAZ micellar binding constant of PS^? in the presence of NaX. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 288–294, 2001