Abstract
The effects of cetytrimethylammonium bromide (CTABr) micelles on pseudo first-order rate constants ( k obs) for the alkaline hydrolysis of N-hydroxyphthalimide (NHPH) have been studied at different NaOH and NaBr concentrations. Pseudo first-order rate constants were treated with a pseudo-phase ion-exchange model of micelles. The rate constants for micellar-mediated reactions are independent of NaBr concentration, while the binding constant of anionic NHPH with CTABr miceles decreases with increasing NaBr concentration. The rate of reaction in the micellar pseudo-phase is significantly smaller than that in the aqueous pseudo-phase. The effects of KBr and KCl concentration on k obs at constant CTABr and NaOH concentrations reveal that an increase in KBr or KCl concentration causes the expulsion of micellized anionic NHPH molecules (NHP M −) from the micellar pseudo-phase to the aqueous pseudo-phase. Bromide ions expel NHP M − more strongly than chloride ions.
Published Version
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