Solubilization of 2-phenylethanol by dodecyldimethylamine oxide in aqueous solution

• Published in: Langmuir Vol. 7; no. 1; pp. 95 - 100
• Main Authors: Uchiyama, Hirotaka, Christian, Sherril D., Scamehorn, John F., Abe, Masahiko, Ogino, Keizo
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.01.1991
• Subjects: 400201 - Chemical & Physicochemical Properties; ALCOHOLS; Chemistry; Colloidal state and disperse state; DATA; ETHANOL; Exact sciences and technology; EXPERIMENTAL DATA; General and physical chemistry; HYDROXY COMPOUNDS; INFORMATION; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; MEASURING METHODS; MICELLAR SYSTEMS; Micelles. Thin films; NUMERICAL DATA; ORGANIC COMPOUNDS; PH VALUE; SOLUBILITY; SURFACTANTS; Micelle; Aqueous solution; Solubilization; Amphoteric surfactant
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la00049a019

The solubilization of 2-phenylethanol (PEA) was measured over a wide range of solute activities and pH values by using dodecyldimethylamine oxide (DDAO) as the surfactant. The DDAO in micellar form is all cationic (protonated) at low pH and all nonionic at high pH. At intermediate pH levels, the DDAO forms mixed micelles containing both the cationic and nonionic forms of surfactant. Thus, measurement of the solubilization of PEA as a function of pH produces solubilization data as a function of mixed micelle composition for this amphoteric surfactant. The solubilization equilibrium constant was found to decrease with increasing mole fraction of PEA in the micelle for all pH values and to be less in the mixed micelles than in either pure cationic or pure nonionic micelles. This latter effect could be due to the hydrophilic region of the mixed micelle being more compact than that of the single-component micelles.