Effect of pH on Solubilization of Benzene Derivatives by Dodecyltrimethylammonium Bromide Micelles

Abstract

Semiequilibrium dialysis measurements have been made to investigate the solubilization of benzene derivatives such as phenol, dimethylphthalate (DMP), benzoic acid (BA) in dodecyltrimethylammonium bromide micelles. Solubilizing capacity and solubilization equilibrium coefficients for phenol whose dissociation degree changes with increasing pH decrease with an increase in the pH of micellar solution, but those for DMP which is not dissociated in water are independent of pH of the micellar solution. Solubilizing capacity and solubilization equilibrium coefficients for BA are independent of pH in the region of pH=5.5-9.0 where BA almost dissociates in water.
It is found that solubilization of the benzene derivatives is strongly dependent on their dissociation degree and polar groups.