Effects of organic salts on the rate of intramolecular general base-catalyzed piperidinolysis of ionized phenyl salicylate in the presence of cationic micelles

Pseudo-first-order rate constants (k(obs)), obtained for the cleavage of io nized phenyl salicylate (PS-) at constant [NaOH], [MeCN], [CTABr](T) (total concentration of cetyltrimethylammonium bromide), [Pip](T) (total concentr ation of piperidine) and varying concentrations of sodium o-, m- and p-tolu ate ([MX]), follow the relationship: k(obs)=(k(0)+thetaK[MX])/(1+K[MX]), wh ere theta and K are empirical parameters. The values of theta are almost in dependent of [CTABr](T), while the K values decrease with increasing [CTABr ](T) within its range 0.005-0.020 mol dm(-3). The values of theta and K are explained in terms of a pseudophase model of the micelle coupled with an e mpirical relationship: K-S=K-S(0)/(1+k(X/S)[MX]), where K-S is the CTABr mi cellar binding constant of PS- in the presence of MX. The value of K-X/S, f or the o-toluate ion is nearly 2.5-fold smaller than those for the m- and p -toluate ions. The values of theta/(k(W)(n)[Pip](T)) {where k(W)(n)[Pip](T) =k(obs) at [CTABr](T)=[MX]=0} vary from nearly 0.5 to 0.6 within the [CTABr ](T) range 0.005-0.020 mol dm(-3).