2,5-二甲基十四烷基苯磺酸钠异构体的合成及其EACN值的测定

以对二甲苯和不同碳数的酰氯为原料,经酰化、格氏反应、催化加氢及磺化中和等步骤合成了亲水基在碳链不同位置的3种同分异构体,通过正交实验确定烷基苯酮合成的最优化条件:n(对二甲苯):n(酰氯):n (AlCl_3)=3:1:1.3,滴加酰氯时体系温度17℃,反应时间为4.5 h,在上述条件下得到烷基苯酮收率为76.4%～78%。采用电喷雾质谱和核磁共振氢谱对合成磺酸盐进行结构表征,用两相滴定法测定产物含有效物为97%以上,配制0.1%单组分异构体磺酸盐水溶液对烷烃进行界面张力扫描,测定表面活性剂亲水基在碳链4,6,7号位置的EACN值分别为7,12,17。

SYNTHESIS OF ISOMERIC SODIUM 2,5-DIMETHYLTETRADECYLBENZENE SULFONATES AND DETERMINATION OF THE EACN VALUE

Three isomers of sodium 2,5-dimethyltetradecylbenzene sulfonate with the hydrophilic group attached to different carbon of the long chain were synthesized from p-xylene and different acyl chloride through five-step process involving Friedel-Crafts reaction,Grignard reaction,catalytic hydrogenation, sulfonation and neutralization.The optimum conditions for synthesizing alkylphenyl ketone screened by orthogonally arranged experiments were found as follows:the addition of acyl chloride at 17℃,the molar ratio of p-xylene to acyl chloride 3:1,molar ratio of AlCl_3 to acyl chloride 1.3:1 and reaction time 4.5 h.Under these conditions,the yield of alkylphenyl ketone was 76.4%- 78%.The structures of the sulfonates were characterized by ESI-MS and ~1H NMR.The mass fractions of the active substances in the final products were all above 97%determined by two-phase titration. Through interfacial tension scanning,the EACN values were determined to be 7,12 and 17,respectively, for the isomers(0.1%) with the hydrophilic group attached to the No.4,No.6 and No.7 carbon of the long chain.