2-羟基-3-辛基-5-长链烷基苯磺酸钠的合成及表面活性

以脂肪酸、苯酚为原料,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,合成出了2-羟基-3-辛基-5-长链烷基苯磺酸钠表面活性剂。两相滴定法测定了产物的质量分数均大于99%;用核磁共振氢谱、傅立叶红外光谱和质谱对产物进行了结构鉴定。用悬挂滴法测定了30℃时该系列表面活性剂的表面张力。实验发现,纯水溶液中表面活性剂的临界胶束浓度(CMC)达到10-6mol/L数量级,临界胶束浓度下的表面张力(γCMC)均小于28 mN/m;随着苯环上长链烷基碳数(n=8,10,12)的增加,CMC降低,分别为1.06×10-5,3.35×10-6,2.65×10-6mol/L;而γCMC变化不明显,分别为26.77,26.89,27.22 mN/m。结果表明,此类表面活性剂具有比较好的表面活性。

Synthesis and Surface Properties of Sodium 2-Hydroxy-3-octyl-5-alkylbenzenesulfonates

Three novel surfactants,sodium 2-hydroxy-3-octyl-5alkylbenzenesulfonates,were synthesized from fatty acid and phenol through Friedel-Crafts acylation,esterification,Fries rearrangement,Pd-catalyzed hydrogenation,sulfonation and neutralization.The contents of sodium 2-hydroxy-3-octyl-5-alkylbenzenesulfonates in the products,determined by two-phase titration,were all above 99%.The structures were characterized by ~1HNMR,IR and MS methods.The critical micelle concentration(CMC) and the surface tension at the CMC(γ_(CMC)) of the surfactants in aqueous solution at 30 ℃ were measured by means of the pendant drop method.The values of CMC(mol/L~3) reached to be of the order of magnitude of 10~(-6) and the values of γ_(CMC) were lower than 28 mN/m.The change of carbon atom number(n=8,10,12) of the substituted hydrophobic chain of benzene ring showed no obvious influence on γ_(CMC)(respectively 26.77 mN/m,26.89 mN/m,27.22 mN/m),however,CMC decreased as the number of carbon atoms increased(respectively 1.06×10~(-5) mol/L,3.35×10~(-6) mol/L,2.65×10~(-6) mol/L).The experiment results showed that these surfactants have high surface activities.