烷基苯磺酸盐Gemini表面活性剂的结构与界面性质

以烷基酰氯为原料,经傅克酰基化反应、格林反应、催化氢化还原及磺化、中和等步骤,合成了10-4-10、12-4-12和10-6-10(10和12代表疏水基碳数,4和6代表连接基团碳数)3种不同结构的双烷基双苯双磺酸盐Gemini表面活性剂,并用核磁共振氢谱和电喷雾质谱对产物进行了结构鉴定。用旋滴法测定了其水溶液与正庚烷的界面张力,发现磺酸盐Gemini表面活性剂的CMC比对应的传统的表面活性剂的CMC低两个数量级,并且随着疏水基碳数或连接基团碳数的增加而降低。10-4-10、12-4-12和10-6-10的饱和吸附面积(Amin)分别为0.23、0.35和0.97 nm2,饱和吸附量(Γmax)分别为7.37×10-10、4.65×10-10和1.72×10-10mol/cm2,临界胶束浓度下的界面张力(γCMC)分别为3.60、3.06和1.89 mN/m。

Structures and Interfacial Properties of Alkylbenzenesulfonate Gemini Surfactants

Three dialkyldibenzenedisulfonate gemini surfactants with different structures 10-4-10,12-4-12 and 10-6-10(10,12 and 4,6 are referred to as the carbon numbers of the hydrophobic chain and those of the spacer respectively) were synthesized through five-step process,including Friedel-Crafts acylation,Grignard reaction,Pd-catalyzed hydrogenation,sulfonation and neutralization.Their structures were identified by 1HNMR and ESI-MS.The interfacial tension between anionic sulfonate gemini surfactant solution and heptane was measured by spinning drop method.It was found that CMC's of gemini surfactants were two orders of magnitude lower than those of the corresponding monomeric surfactants,and the CMC increased with the increase of carbon numbers of the hydrophobic chains or the spacer.A(min)(the minimum area per surfactant molecule) of 10-4-10,12-4-12 and 10-6-10 are 0.23,0.35 and 0.97 nm2 respectively,their Γ(max)(the maximum surface excess concentration) are 7.37×10(-10),4.65×10(-10) and 1.72×10(-10) mol/cm2 respectively,and their γ(CMC)(the interfacial tension at CMC) are 3.60,3.06 and 1.89 mN/m respectively.