Nucleophilicity of bromide ion in mixed cationic/sulfoxide micelles

Abstract

Addition of the non-ionic surfactant, n-decyl methylsulfoxide (C₁₀SO) to aqueous cetyltrimethylammonium bromide (CTABr) inhibits the micellar-mediated reaction of Br^– with bound methyl naphthalene-2-sulfonate (MeONs). The concentration of Br^– at the micellar surface is reduced due to an increase in the fractional micellar ionization, α, and in the volume of the micellar pseudophase, which slows the reaction of Br^–. These concentration effects are partially offset by an increase in the second-order rate constant in the micellar pseudophase on addition of C₁₀SO.