MICELLAR KINETICS OF ACYL TRANSFER FROM N-NONANOYLOXYBENZENESULFONATEAND PHENYL NONANOATE BLEACH ACTIVATORS TO HYDROGEN-PEROXIDE AND PERNONANOIC ACID - EFFECT OF CHARGE ON THE SURFACTANT AND ACTIVATOR

The effect of surfactants on the kinetics of the title reactions is an alysed using a combined multiple micellar pseudophase model and transi tion state pseudoequilibrium constant approach which leads to the mice llar association constants of the reactants and the apparent (virtual) micellar association constants of the transition states. These associ ation constants reflect the stabilisation of the reactants and transit ion states, respectively, by the micelle compared with their stability in the bulk aqueous phase. For the reaction of n-nonanoyloxybenzenesu lfonate with pernonanoate in the presence of sodium dodecyl sulfate (S DS) the apparent micellar association constant of the transition state is larger than the micellar association constant of the activator; th is is consistent with micellar catalysis, whilst micellar inhibition o ccurs with the anion of hydrogen peroxide, The micellar association co nstant of phenyl nonanoate with SDS is four orders of magnitude greate r than that of n-nonanoyloxybenzenesulfonate due to the absence of the negatively charged sulfonate group, whilst the apparent micellar asso ciation constant of the transition state for its reaction with pernona noate is more than an order of magnitude less. In the non-ionic surfac tant Brij-35, the micellar association constant of n-nonanoyloxybenzen esulfonate and the corresponding apparent quantity for the transition state for the reaction with the hydroperoxide anion are, respectively, about one and two orders of magnitude greater than in SDS.