Solubilization and separation of dicarboxylic acids by surfactant micelles and polyelectrolytes

Semi-equilibrium dialysis (SED) and micellar enhanced ultra filtration (MEUF) methods are used to determine the extent of solubilization of water-insoluble compounds by surfactant and polyelectrolyte. In this study, solubilization of ortho-, meta- and para-phthalic acids (OPA, MPA and TPA), 1,4- and 2,6-naphthalene dicarboxylic acids (1,4-NDCA and 2,6-NDCA) into hexadecylpyridinium chloride (CPC), and the behavior of these acids to bind to the polyelectrolyte ionizable groups were investigated at 25 degreesC, using SED and MEUF methods. Polydimethyldiallylammonium chloride (PDMDAAC) is used in this study. It was found that the solubilization of organic acids decreases with increasing the solute mole fractions in micelles. Also, the best separation occurs at the lowest concentration of the phthalate ions and high concentrations of either CPC or PDMDAAC. The results support the idea of charge interaction between the anionic dicarboxylate groups and cationic surfactant or polyelectrolyte. The results also show that the presence of a second phenyl ring does not greatly affect the solubilization behavior of the acids.