NUCLEOPHILICITY OF BROMIDE ION IN MIXED CATIONIC SULFOXIDE MICELLES

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