The methanolysis of ionized phenyl salicylate, PS-, has been studied in the absence and presence of 0.03 M cetyltrimethylammonium bromide, CTABr, at 0.01 M NaOH and within the CH3OH content range of 10-80 or 90% (v/v). The pseudo-first-order rate constants, K-obs, remain unchanged with change in [CTABr](T) from 0.0 to 0.03 M at greater than or equal to 65% (v/v) CH3OH. The ratio, K-obs (0.0 M CTABr)/k(obs) (0.03 M CTABr) decreases from 4.6 to 1.1 with increase in CH3OH content from 10 to 60% (v/v). At the constant temperature and [CH3OH](T), the rate constants, k(obs), show a decrease with increase in [CTABr](T). These results are explained in terms of a pseudophase model of micelle. At 30 degrees C, the pseudo-first-order rate constants, k(M)(MeOH), for the reaction of CH3OH with PS- in the micellar pseudophase and cmc of CTABr increase from 9.63 x 10(-4) and 1.8 x 10(-4) to 78.8 x 10(-4) s(-1) and 60.0 x 10(-4) M, respectively, while the binding constants, K-1, decrease from 8080 to 39 M(-1) with increase in methanol content from 10 to 50% (v/v). Similar results are obtained at different temperatures ranging from 25 to 45 degrees C. The activation parameters, Delta H* and Delta S*, for k(M)(MeOH) are larger than those for k(NM)(MeOH) (where k(NM)(MeOH) represents pseudo-first-order rate constant for the reaction of CH3OH with PS- in the nonmicellar pseudophase) at 10, 20, and 30% (v/v) CH3OH. These results are attributed to the increased ground-state stability of a monomeric methanol in the micellar pseudophase compared to that in the nonmicellar pseudophase. The thermodynamic parameters, Delta H-o and Delta S-o, for binding constant, K-1, reveal the decrease from -8.6 and -10.5 to -14.1 kcal/mol and -31.9 cal/(K mol), respectively, with increase in CH3OH content from 10 to 30% (v/v). Significantly lower values of k(M)(MeOH) compared to those of k(NM)(MeOH) low contents of CH3OH are ascribed to (i) reduced [CH3OH] in the micellar pseudophase, where PS- molecules exist, compared to [CH3OH] in the nonmicellar pseudophase and (ii) partial loss of the efficiency of intramolecular general base catalysis due to probable ion-pair formation between anionic site of micellized PS- molecule and the cationic micellar headgroups.