The Solubilization of Orange OT in Anionic Surfactant Solutions

• Published in: Bulletin of the Chemical Society of Japan Vol. 44; no. 6; p. 1503
• Main Authors: Hayano, Shigeo, Shinozuka, Noriko
• Format: Journal Article
• Language: English
• Published: Tokyo Chemical Society of Japan 01.06.1971
• ISSN: 0009-2673; 1348-0634

Orange OT (1-o-tolyl-azo-β-naphthol) solubilized in sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (SDBS) solutions showed a well-defined irreversible polarographic wave. The proportionality of the limiting current to the square root of the mercury height and to the dye concentration indicates the wave to be diffusion-controlled. It is noted that the anionic surfactants showed the waves due to the adsorption-de-sorption and reorientation of the surfactant molecules on the electrode. The apparent diffusion coefficients of the solubilized dye calculated from the polarographic data were in good agreement with those of the anionic surfactant micelle with electrolyte. We may conclude that the polarographic diffusion coefficient of the solubilized dye is equal to that of the micelle of the solubilizer surfactant. The marked surfactant concentration dependence of the diffusion coefficient was observed with both surfactants and was attributed to the interaction of the micelles. The transfer coefficient of the electrode reaction of Orange OT increased with an increase in the concentration of the surfactant. This tendency is different from the effect of the surface-active agents on the transfer coefficient in the reduction of inorganic ions. From the experimental observations, it seems that the electrode reaction of the solubilized dye is little effected by the charged micelles.