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分别以十二烷基二甲基叔胺、十四烷基二甲基叔胺和对二氯苄(XDC)为原料,“一步法”合成了两种季铵盐双子表面活性剂,通过正交实验优化了合成条件,结果表明,当n(叔胺)∶n(XDC)=2.4∶1、反应温度75℃、反应时间2 h时,XDC转化率达到100%;产物结构经红外光谱(FTIR)、核磁共振氢谱(1HNMR)和碳谱(13CNMR)进行了确认。研究了其表面活性,结果表明:25℃时,碳链长度分别为12和14时,表面活性剂临界胶束浓度(CMC)分别为1.36×10-5和2.56×10~(-6)mol/L,表面张力(γCMC)分别为40.71和35.37 m N/m;p C20值分别为5.63和6.18;表面过剩吸附量(Γmax)分别为2.41×10~(-6)和3.09×10~(-6)mol/m~2;分子最小截面积(Amin)分别为0.69和0.54 nm~2。动态表面张力参数n值分别为0.85、0.74,t*分别为1.05和0.27 s,R1/2分别为14.11和69.79 m N/m/s,R=14的双子表面活性剂的动态表面张力优于R=12时。该季铵盐双子表面活性剂与结构相似的季铵盐表面活性剂如十六烷基三甲基溴化铵(CTAB)相比CMC低2个数量级。
Two kinds of quaternary ammonium salt gemini surfactants were synthesized by the one-step method using dodecyl dimethyl tertiary amine, tetradecyl dimethyl tertiary amine and p-dichlorobenzyl chloride (XDC) The synthesis conditions were optimized by orthogonal experiments. The results showed that the conversion rate of XDC reached 100% when n (tertiary amine): n (XDC) = 2.4:1, reaction temperature 75 ℃ and reaction time 2 h. Spectra (FTIR), 1 HNMR and 13CNMR were confirmed. The results showed that the critical micelle concentration (CMC) of surfactant at 25 ℃ was respectively 1.36 × 10-5 and 2.56 × 10 ~ (-6) mol / L and the surface tension (γCMC) were 40.71 and 35.37 mN / m, respectively, and the values of p C20 were 5.63 and 6.18 respectively. The excess surface adsorption capacity (Γmax) was 2.41 × 10 -6 and 3.09 × 10 ~ -6) mol / m ~ 2. The minimum molecular cross-sectional area (Amin) was 0.69 and 0.54 nm ~ 2, respectively. The dynamic surface tension parameters n were 0.85,0.74, t * were 1.05 and 0.27 s, R1 / 2 was 14.11 and 69.79 m N / m / s, respectively. The dynamic surface tension of gemini surfactants with R = 14 was superior to R = 12 o’clock. The quaternary ammonium salt gemini surfactant is structurally similar to quaternary ammonium surfactants such as cetyltrimethylammonium bromide (CTAB) by two orders of magnitude lower than the CMC.