2,4-二甲基-5-(7'-十三烷基)-苯磺酸钠的界面活性

研究了实验室自制的高纯度2,4-二甲基-5-(7'-十三烷基)-苯磺酸钠(C13-7Sa)的界面活性。采用旋滴法测定C13-7Sa水溶液-正构烷烃体系的油-水界面张力，采用滴体积法测定C13-7Sa纯水溶液的表面张力。考察了水溶液中NaCl、异戊醇和C13-7Sa浓度对C13-7Sa水溶液-正癸烷体系油-水界面张力的影响。结果表明，使C13-7Sa水溶液-正癸烷体系油-水界面张力达到最低值的C13-7Sa水溶液最适宜的NaCl质量分数、异戊醇体积分数和C13-7Sa质量分数分别为0.15%、1.8%和0.1%，此时，体系油-水界面张力降到1.3×10-3mN/m；C13-7Sa水溶液的临界胶束浓度(cmc)为1.28×10-4mol/l，最小表面张力(γcmc)为26.53mN/m。说明C13-7Sa具有较好的界面活性。

INTERFACE PROPERTIES OF SODIUM 2,4-DIMETHYL-5-(7'-TRIDECYL) BENZENE SULFONATE

The interfacial properties of the solution of sodium 2,4-dimethyl-5-(7'-tridecyl )benzene sulfonate codenamed C13-7Sa with high purity synthesized in the laboratory was studied. The oil-water interfacial tensions of the system of C13-7Sa solution and n-hydrocarbon were measured by spinning drop method and the surface tension of dilute aqueous solutions of C13-7Sa was measured by drop-volume method. The effects of the NaCl, isoamylol and C13-7Sa concentrations in C13-7Sa solution on oil-water interfacial tension of the system of C13-7Sa solution and n-decane were investigated. The results showed that the best conditions, under which the oil-water interfacial tension of C13-7Sa solution and n-decane system reached 1.3×10-3 mN/m, were NaCl mass fraction of 0.15%, alcohol volume fraction of 1.8% and C13-7Sa mass fraction 0.1% in C13-7Sa solution. The critical micelle concentration (cmc) of C13-7Sa dilute aqueous solution was 1.28×10-4mol/l, at which the surface tension γcmc was 26.53mN/m. C13-7Sa had good interfacial properties.