Solubilization of triphenylamine, triphenylphosphine, triphenylphosphineoxide and triphenylmethanol in single and binary surfactant systems

Solubilization and co-solubilization of triphenyls (TPs) viz., triphenylphosphine (TPP), triphenylphosphineoxide (TPPO), triphenylamine (TPA) and triphenylmethanol (TPM) were studied in various single and binary surfactant systems at 25 °C using UV–visible spectroscopy and HPLC. The solubilization capacities of different micelles towards TPs were found to be a function of the nature and structure of solubilizates, locus of solubilization, size of micelles and the nature of interactions between the solubilizate and micelles. The effect of surfactant mixing on the solubilization of TPs was evaluated using the Regular Solution Approach (RSA). The solubility enhancement of TPs within mixed micelles relative to that observed in single surfactant systems was explained in light of the structural micellar changes associated with the mixing of ionic and non-ionic surfactants. Moreover, kinetics of oxidation of TPP by hydrogen peroxide investigated in these surfactant systems was found to be sensitive to the nature of micelle and the locus of solubilization of TPP within the micelles.

Correlation of λmax (nm) of Triphenyl phosphine oxide (TPPO) in various surfactants and the model solvents at 25 °C to provide an insight into its locus of solubilization in these surfactant assemblies.Figure optionsDownload high-quality image (165 K)Download as PowerPoint slideHighlights
► We report solubilization of triphenyls in single and mixed surfactant systems.
► The solubilization capacity of the micelles was dependent on the locus of solubilization and structure of the solubilizates.
► The extent of co-solubilization is strongly affected by the competition for the same solubilization site.
► The locus of solubilization of triphenylphosphine within micelles significantly affects its rate of oxidation.