Acid–base equilibria in aqueous micellar solutions. Part 1.—‘Simple’ weak acids and bases

Abstract

The acid–base equilibria of a number of phenols, amines and carboxylic acids in aqueous micellar solutions and organic solvent–water mixtures have been examined. For the majority of the molecules investigated, the differences between the pK_a values in pure water and the apparent pK_a values when the molecules reside within micellar interfacial microenvironments can primarily be ascribed to the differenes between the mean intrinsic solvent properties of the interfacial and bulk phases, with an additional contribution from the electrostatic micellar surface potential in the case of the charged aqueous micellar solutions.