以聚氧乙烯醚为连接基的烷基苯磺酸钠Gemini表面活性剂的合成和表面活性

 以脂肪酸、苯酚、聚乙二醇为原料，经酰化反应、酯化反应、Fries重排、氢化还原反应、磺化以及中和反应等步骤，合成出一系列含有不同长度聚氧乙烯醚中间连接基团（-(CH2CH2O)x-, x =1, 2, 3, 4, 8）的长链烷基苯磺酸钠Gemini表面活性剂。采用FT-IR、1H NMR 和电喷雾质谱(ESI-MS)对产物进行了结构鉴定。以Wilhelmy-plate法测定了该系列表面活性剂纯水溶液在30℃时的表面张力。结果表明，纯水溶液中表面活性剂的临界胶束浓度 (CMC) 数量级达到10-4 mol/L，临界胶束浓度下的表面张力 ( cmc) 在30~40 mN/m范围；随着中间连接基团长度(x = 1, 2, 3, 4, 8) 的增加，CMC先降低后升高，依次为5.94×10-4、1.88×10-4、1.16×10-4、1.12×10-4、5.18×10-4 mol/L；同时 cmc逐渐降低，分别为36.88、39.17、38.93、37.85、32.02 mN/m。此类表面活性剂具有比较好的表面活性。

SYNTHESIS AND SURFACE ACTIVITY OF GEMINI SURFACTANTS OF SODIUM ALKYLBENZENE SULFONATES WITH POLYOXYETHYLENE SPACERS

A series of Gemini anionic surfactants, sodium alkylbenzene sulfonates, with the same nature except the spacer length of the polyoxyethylene chain were synthesized from fatty acid, phenol and oligoethylene glycol through Friedel-Crafts acylation, esterification, Fries rearrangement, Pd-catalyzed hydrogenation, sulfonation and neutralization. The structures of the products were characterized by FT-IR, 1H NMR and ESI-MS methods. The critical micelle concentration (CMC) and the surface tension ( cmc) at the CMC of the surfactants in aqueous solution at 30℃ were measured by means of the Wilhelmy-plate method. The order of magnitude of their CMC reached to 10-4 (mol/L) and the values of their cmc were in the range of 30-40 mN/m. The values of CMC were observed to decrease initially and then increase, which were 5.94×10-4，1.88×10-4，1.16×10-4 ，1.12×10-4，5.18×10-4 mol/L, respectively, and the values of cmc were observed to increase initially and then decrease, which were 36.88，39.17，38.93，37.85，32.02 mN/m, respectively, as the spacer length of the polyoxyethylene chain (x = 1, 2, 3, 4, 8) increased. The experiment results showed that these surfactants have high surface activities.