KINETIC TREATMENT OF THE REACTION OF M-CHLOROPERBENZOIC ACID AND IODIDE IN MIXED ANIONIC NON-IONIC MICELLES/

Catalysis and inhibition of the title reaction in mixed micelles of Br ij-35 and SDS is described. The kinetics are treated using a combined multiple micellar pseudophase model and transition state pseudoequilib rium constant approach that was previously used for the catalysis and inhibition of the reaction of peracids and iodide in non-ionic and ani onic micelles, respectively (D. M. Davies, N. D. Gillitt and P. M. Par adis, J. Chem. Soc., Perkin Trans. 2, 1996, 659). In the present mixed micellar system the following factors are taken into account: (i) the mole ratio of the surfactants in the mixed micelle, which is the rele vant quantity for the micellar kinetics and is different from the stoi chiometric mole ratio of the surfactants; (ii) non-ideal mixing of the surfactants, which also influences the composition of the mixed micel le; (iii) the ideal behaviour of the apparent molar volume of micelliz ed surfactant in mixed micelles; and (iv) deviations from ideality of the partitioning of reactants and transition state between mixed micel les and the bulk aqueous phase. Logarithms of micellar association con stants of the reactants and transition state in the two surfactants ha ve been obtained, together with parameters closely related to the exce ss Gibbs function associated with the deviations from ideality describ ed by (iv). The relationship between the parameters that describe non- ideal mixing of the surfactants in (ii) and the deviations from ideali ty in (iv) is discussed.