INFLUENCE OF CETYLTRIMETHYLAMMONIUM BROMIDE 1-HEXANOL AND CETYLTRIMETHYLAMMONIUM BROMIDE 1-OCTANOL MIXED MICELLES ON THE BASIC HYDROLYSIS OF CRYSTAL VIOLET - DIFFERENT THEORETICAL APPROACHES

1-Hexanol and 1-octanol incorporation into CTAB micelles mainly produces an inhibitory effect on the basic hydrolysis of crystal yiolet. The concentration of both alcohols, which saturate the micellar aqueous solution, is small, and the alcohol amount in the micellar phase does not greatly affect physical properties of the micelle such as cmc, micellar aggregation number, micellar effective dielectric constant, and fraction of neutralized micellar head groups according to our conductivity and steady-state fluorescence measurements. The kinetic results are analyzed on the basis of the pseudophase ion-exchange equilibrium model and on an electrostatic treatment that considers ion distribution around micelles according to the nonlinearized Poisson-Boltzmann equation, with specific adsorption between the micellar surface and bromide ions. This treatment predicts that substrate to micelle binding depends on the micellar surface potential. In order to explain the results, it is necessary to consider that both alcohols displace the substrate from the micellar to the aqueous phase, which is related to the inhibitory effect we found. © 1990, American Chemical Society. All rights reserved.