系列十二烷基二甲苯基磺酸钠的合成与表面性能

Synthesis and Surface Properties of a Series of Sodium Dodecyl Xylenesulfonate Isomers

以酰氯、邻二甲苯为原料,经傅-克酰基化反应、格氏反应、还原反应、磺化及中和5步反应,合成了6种结构明确的十二烷基二甲苯基磺酸钠异构体。用FT-IR、ESI-MS和1HNMR测试技术鉴定了中间产物和最终产物的结构。用滴体积法测定表面活性剂水溶液25℃时的表面张力,从而确定其临界胶束浓度,研究了支链结构对其表面性质的影响。6种表面活性剂(化合物Ⅰ～Ⅵ)的临界胶束浓度CMC(mmol/L)和表面张力γCMC(mN/m)分别为:Ⅰ0.25和30.00;Ⅱ0.50和28.21;Ⅲ0.79和28.10;Ⅳ1.00和27.01;Ⅴ2.00和26.41;Ⅵ2.50和26.40。结果表明,随着苯环由边缘移动至长链烷基的中间,表面活性剂的CMC增高,γCMC减小。

Six isomers of sodium dodecyl xylenesulfonate were synthesized from chloride and o-xylene via a five-step process involving Friedel-Crafts reaction, Grignard reaction, reduction, sulfonation, and neutralization. The structures of the intermediates and the final products were characterized by IR, ESI-MS and ^1H NMR. The surface tensions of dilute aqueous solutions of product were measured at 25 ℃ by drop-volume method and then the critical micelle concentration （CMC） was determined. The values of C MC （mmol/L） and γCMC （raN/m） are Ⅰ. 0.25, 30.00 ; Ⅱ.0. 50, 28.21 ; Ⅲ. 0. 79, 28.10; Ⅳ. 1.00, 27. 01 ; Ⅴ. 2.00, 26. 41 ; Ⅵ. 2. 50, 26.40. These results indicate that the CMC increases but the γCMC decreases as the position of benzene ring is moved from the edge to the middle of the long chain alkyl.