Modelling of micellar effects upon substitution reactions with moderately concentrated hydroxide ion

Cationic micelles of cetyltrimethylammonium chloride and bromide (CTACl and CTABr) speed reactions of 2,4-dinitro-1-naphthyl chloride (DNNC) and p-nitrophenyl diphenyl phosphate (pNPDPP) with OH–. The pseudophase ion-exchange model fits the data for reaction with [OH–] < 0.05 mol dm–3, but the reaction is faster than predicted at higher ratios of [OH–]. The deviations from theory are largest with high ratios of [OH–] to [Cl–] or [Br–] and are larger in CTABr than in CTACl. A mass-action-like model with each anion binding independently to the micelle fits the data for 10–3–0.5 mol dm–3 OH–.