Synthesis And Surface Activity Properties Of A Series Of Gemini Surfactants

Gemini surfactants are a new class of surfactant for their novel structure and unique properties, and thus it is significantly important to study and develop the Gemini surfactants. In this paper, the environment-friendly synthesis process of the Gemini surfactants was optimized based on the current study and application of surfactant and the Gemini quaternary ammonium cationic surfactants and the zwitterionic Gemini surfactants were synthesized.The intermediate products containing chlorine substituent was synthesized using TBAB as phase transfer catalyst, docecyl branched alchohol, n-dodecanol, n-tetradecyl alcohol and n-hexadecanol as raw materials which separately reacted with epichlorohydrin. Moreover, four quaternary ammonium gemini surfactants were synthesized through the reaction of intermediate product and tetramethylethylenediamine. The intermediate products were sulfonated by chlorosulfonic acid and neutralized by NaOH solution in order, and the four zwitterionic gemini surfactants were obtained. They were recrystallized and dried at vacuum, at last, they were analyzed by IR.Surface tensions of the two series surfactant solution were measured by drop volume method at 25℃under eight different concentrations, and the critical micelle concentration (cmc), excess adsorption amount (Γ_max), single molecule adsorption area (A_min) were obtained from these data; meanwhile, the sterilization rate and the emulsifying properties of the surfactants were determined.The results showed that all the eight Gemini surfactants had high surface activity and good emulsifying properties. In the two class surfactants, the surfactants using n-tetradecyl alcohol as raw materials have lower surface tension compared with other surfactants, in addition, both the Gemini quaternary ammonium cationic surfactants and zwitterionic Gemini surfactants (0.1wt%) have good emulsifying properties, while the emulsifying properties of the branched surfactants were better than that the surfactants with the same number of carbon straight chain. sterilization rate of quaternary ammonium gemini surfactants and emulsifying properties of four quaternary ammonium surfactant and four gender surfactant were determined. The results showed that the eight gemini surfactants have higher surface activity and good emulsifying properties respectively.