Solubilization and transfer free energy of some organic compounds from bulk aqueous phase to micelle of a new type of surfactant
A new type of surfactant, 3-alkoxyl-2-hydroxylpropyltrimethyl ammonium bromide (CnH2n+1OCH2CH(OH) CH2N(CH3)3+Br-, abbreviated as RnTAB, n = 8, 12, 14, 16) was synthesized. The solubilization of n-pentanol, n-hexanol, n-heptanol, benzyl alcohol, n-hexane, benzene, toluene, heptane, and carbon tetrachloride in aqueous solutions of RnTAB, sodium dodecyl sulfonic(R12 SO3Na), and in the mixed solution of R16 TAB/R12SO3Na have been studied by the microtitration method. The experimental results show that the solubilized amounts of the organic compounds increase with the growing of the hydrocarbon chain of RnTAB, and the solubilizing ability of the binary system is lower for polar substances than for a mono-surfactant aqueous solution. "V" isothermal curves of the solubilized amount of polar substances have been observed, and the minimum solubilized amount is at the molar ratio 1:1 of R16 TAB/R12SO3Na. However, the solubilizing ability of mixed surfactants for non polar substances is higher than that for a mono-surfactant solution, the solubilizing isotherm curves present a "saddle" shape, and the maximum solubilized amount is at the molar ratio 1:1 of R16TAB/R12SO3 Na too. The length of hydrophobic chains of surfactant and the polarity of the organic compound affect the transfer free energy from aqueous to micelle phase. The longer the hydrophobic chain of RnTAB and the lower the polarity of the organic compound, the more easily will the compound transfer from aqueous phase to micelle phase. Copyright © Taylor & Francis, Inc.
Wei, XL; Yin, BL; Liu, J; Sun, DZ; Li, GZ
Journal of Dispersion Science and Technology
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