Fine Synthesis And Properties Of Sodium Pentadecyl-aryl Sulfonates

Four kinds of isomers of sodium pentadecyl aryl sulfonates were synthesized from fatty acids, m-xylene andα-chloride through five-step process, involving Friedel-Crafts reaction, Grignard reaction, reducation, sulfonation and neutralization. Part of physical property of intermediates were measured, and the structures of the intermediates and final products were characterized by FT-IR, ¹³C NMR and ¹H NMR.The surface properties of sodium pentadecyl m-xylene sulfonates in pure water and 0.0393mol·L^-1 isopropanol solution were measured at 25℃. The measurements indicated that the critical micelle concentration (cmc) increased while the surface tension at the cmc (γcmc) decreased. And with the addition of isopropanol the cmc decreased apparently. The interfacial tension between the solutions of sodium pentadecyl m-xylene sulfonates and a serie of n–alkanes were studied by Spinning drop method at 45℃, nmin values of m-C15-2S,m-C15-4S,m-C15-6S,m-C15-8S were determined as 10, 12, 12 and 15; the effects of the concentration of NaCl and isoamylol were also investigated.The foamability of the sulfonates were measured by Ross-Miles foaming apparatus, the measurements indicated that the height of the foam increased at first and then became smooth ,the stability of the foam decreased at first and then became smooth as the surfactant concentration increasing at 45℃; the height of the foam increased and the stability decreased with the growing of the temperature.The effects of the concentration of surfactants, NaCl, NaOH, NaHCO₃, n-butyl alcohol or molecular structures of surfactants on pentadecyl aryl sulfonates adsorption on the oil sands of Daqing are discussed at 45℃. The experimental data showed that with the increasing concentration of sulfonate first and then became decreased;with the increasing concentration of NaCl and NaOH the absorption capacity increased; while decreased with the addition of n-butyl alcohol and NaHCO₃; with the moving of the aryl from the terminal to the center of the long alkyl chain the absorption capacity decreased.