Pseudo-first-order rate constants (k(obs)) for the nucleophilic substitution reaction of piperidine (Pip) with ionized phenyl salicylate (PS-), obtained at a constant [PIP](T) (= 0.1 M), [PS-](T)( = 2 x 10(-4) M), [CTABr](T) (cetyltrimethylammonium bromide), <= 0.06 M NaOH, and a varying concentration of.MX ( = 3-FC6H4CO2Na, 3-FBzNa and 4-FC6H4CO2Na, 4-FBzNa), follow the kinetic relationship k(obs) = (k(0) + theta K-X/S[MX])/(1+ K-X/S[MX]) which is derived by the use of the pseudophase micellar (PM) model coupled with an empirical equation. The empirical equation explains the effects [MX] on CTABr micellar binding constant (K-s) of PS- that occur through X-/PS- ion exchange. Empirical constants theta and K-X/S give the parameters F-X/S and K-X/S, respectively. The magnitude of F-X/S gives the measure of the fraction of micellized PS- transferred to the aqueous phase by the limiting concentration of X- through X-/PS- ion exchange. The values of F-X/S and K-X,K-S have been used to determine the usual thermodynamic ion exchange constant (K-X(Y)) for ion exchange process X-/Y- on the CTABr micellar surface. The values of K-X(BR). (where Br = Y) have been calculated for X = 3-FBzNa and 4-FBzNa. The mean values of K-X(Br) are 12.8 +/- 0.9 and 13.4 +/- 0.6 for X- = 3-FBz(-) and 4-FBz(-), respectively. Nearly 3-fold-larger values of K-X(BR) for X = 3-FBz(-) and 4-FBz(-) than those for X = Bz(-), 2-ClBz-, 2-CH(3)Bz(-), and the 2,6-dichlorobenzoate ion (2,6-Cl(2)Bz(-)) are attributed to the presence of wormlike micelles in the presence of > 50 mM 3-FBz(-) and 4-FBz(-) in the [CTABr](T) range of 5-15 mM. Rheological properties such as shear thinning behavior of plots of shear viscosity versus the shear rate at a constant [3-FBz(-)] or [4-FBz(-)] as well as shear viscosity (at a constant shear rate) maxima as a function of the concentrations of 3-FBz(-) and 4-FBz(-) support the conclusion, derived from the values of K-X(Br), for the probable presence of wormlike/viscoelastic micellar solutions under the conditions of the present study.