An empirical approach to study the occurrence of ion exchange in the alkaline hydrolysis of phthalimide in the presence of cationic micelles and inert salts

Pseudo first-order rate constants, kobs, for pH-independent hydrolysis of phthalimide, PTH, obtained at constant [CH3CN], [CTABr]T (total concentration of cetyltrimethylammonium bromide), and varying concentrations of MX (MX = sodium acetate, sodium butanoate, disodium adipate, sodium phenoxyacetate, sodium 4-methoxybenzoate, sodium 3-, 4- and 2-toluate) follow a relationship derived from an empirical equation coupled with a pseudophase model of micelle. This relationship gives an empirical constant (KX/S) whose magnitude is the measure of the ability of an ion, X−, to expel another counterion, S−, from a cationic micellar to the aqueous pseudophase. The empirical KX/S is used to derive the usual ion-exchange constant (KXY). The values of KXBr have been calculated for all X− ions of the present study, and most of the calculated values of KXBr are comparable with the corresponding KXBr values obtained directly by other physical techniques.