Bis(2-ethylhexyl)Sodium 2-Sulfonatosuccinate(Aerosol OT)およびそのリチウムまたはカリウム置換塩の水中におけるミセル形成

概要

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Critical micelle concentrations of bis(2-ethylhexyl) sodium 2-sulfonatosuccinate (Aerosol OT ; abbr. AOT-Na) and its lithium or potassium substituted salt (abbr. AOT-Li or AOT-K) in water were determined by surface-tension measurement at 25-45°. The heat of micelle formation was obtained from heat-of-dilution measurement using a twintype microcalorimeter at 25-45°. Critical micelle concentrations of AOT-Li, AOT-Na, and AOT-K were 3.0,2.5,and 2.3×10^<-3>M at 25°, respectively, and vary slightly with the increase of temperature, showing minimum near 30° for or all salts, which was ascertained from the fact that the enthalpy of micelle formation for these salts changes coincidentally from endothermic(e.g., 0.5 kcal/mole at 25°) to exothermic (e.g., 1.6 kcal/mole at 45°) taking null value at 30°. From these data, the partial molar Gibbs free energy, enthalpy, and entropy of micelle formation were calculated, indicating the significant difference of values according to the kind of counter-ion. The analysis of heat capacitiy, i.e., temperature coefficient of enthalpy, of micelle formation suggests the agglomeration of two hydrophbic chains of these salts, even in monomeric dispersion, in water.
社団法人日本薬学会の論文
1975-11-25