三烷基苯磺酸盐的合成与表面性能研究

为了研究三直链烷基苯磺酸钠的分子结构与表面活性之间的关系,以3,4-二甲基-4-氯苯为原料,经格林试剂交叉耦合反应、氢碘酸改进法还原反应、磺化反应以及中和反应等步骤,合成了2种不同烷基长碳链的三直链烷基苯磺酸钠(分别记为a和b),产物的总收率达45%～53%。用两相滴定法测定产物的纯度均大于99%,并用红外光谱进行了结构鉴定。25℃时用滴体积法测定表面活性剂a和b水溶液的表面张力和临界胶束浓度(cmc),分别为31.15 mN/m,25.48 mN/m和3.28×10-4mol/L,8.13×10-4mol/L。结果表明,随着长碳链碳原子数的增加,表面活性剂的cmc逐渐减小,临界胶束浓度下的表面张力(γcmc)逐渐增大。

Study on synthesis of trialkylbenzene sulfonates and surface properties

In order to study the relationship between the molecular structure and surface activity of sodium 3 linear alkylbenzene sulfonate, two kinds of sodium 3 linear alkylbenzene sulfonate （denoted as a and b） with different carbon chain of alkyl are synthesized using 3,4-dimethyl-4-chlorobenzene as raw material, and after some processes including cross-coupling reaction of Grignard reagent, hydriodic acid improved act of reduction reaction, sulfonation reaction and neutralization reaction. The total yield of the product is 45 % -53%. The purity of the products are both more than 99% by two-phase titration method, and the structural identification is conduc- ted with infrared spectroscopy. The surface tension and critical micellar concentration （cmc） of the aqueous solution of surfactant a and h are measured by drop volume method at 25℃, which is 31.15 mN/m, 25.48 mN/m and 3.28 ×10^-4mol/L, 8.13×10^-4mol/L, respectively. The results show that with the number of carbon atoms of the long carbon chain increasing, the cmc of the two surfactants decreases gradually, and the surface tension under emc （ γcmc ） increases gradually.