Journal of Chemical and Engineering Data, Vol.54, No.3, 1015-1021, 2009
Thermodynamic Properties of Micellization of Sodium Dodecylbenzene Sulfonate in the Aqueous-Rich Region of 1-Pentanol and 1-Hexanol
Apparent molar volumes, Phi v, and isentropic compressibilities, k(s), of the aqueous solutions of anionic surfactant, sodium dodecylbenzene sulfonate (SDBS), have been derived from experimental densities, rho, and speed of sound, u, data measured below 0.40 mol center dot kg(-1) at T = (298.15, 303.15, 308.15, and 313.15) K using an Anton Paar densimeter (DSA-5000). Conductance measurements were also made for aqueous solutions of SDBS to obtain critical micelle concentration at the above temperatures. Apparent molar volumes and isentropic compressibilities of I-pentanol and I-hexanol dissolved in aqueous micellar solutions of SDBS were determined as a function of molalities of surfactant (0.05 and 0.1) mol center dot kg(-1) and alcohols at T = (298.15 and 308.15) K. The standard partial molar volumes, Phi degrees v, and transfer volume, Phi degrees v((tr)), have been calculated for rationalizing various interactions in the studied solutions. Viscosity measurements were made for the above-mentioned alcohols in aqueous solutions of SDBS to obtain relative viscosity and viscosity B-coefficient. The second transition of aqueous sodium dodecylbenzene sulfonate in the postmicellar region has been obtained. Proton NMR chemical shift measurements in micelle solutions containing I-pentanol have also been made, the results of which support the conclusions drawn from thermodynamic measurements.