Ion Binding and Micellar Effects upon Reactions of Carboxylic Anhydrides and Carbonate Esters

Article abstract of DOI:10.1021/jo00346a003

Cationic micelles speed reactions of benzoic anhydride and bis(4-nitrophenyl) carbonate with hydroxide and carboxylate ion.With micellized cetyltrimethylammonium bromide (CTABr) the variation of the first-order rate constant, k_ψ, with can be fitted to the pseudophase ion-exchange model, but this model fails when the counterion of the surfactant is OH^- or carboxylate ion.The variations of k_ψ with concentration of these reactive counterion surfactants fit a kinetic model in which the distribution of the nucleophilic anion between the aqueous and micellarpseudophases depends upon the concentration of nucleophilic ion.Despite the apparent differences between these two models, they predict similar values for the second-order rate constants of reaction of a given anion in the different types of micelles, and the implications of these findings to the interactions of micelles with counterions are discussed.