Synthesis And Properties Of A Novel Zwitterionic Gemini Phosphate Surfactant

A new generation of surfactants, Gemini surfactant has attracted widely attention in some industrial fields and academic research institutions. The Gemini surfactant molecule has two hydrophobic groups and two hydrophilic groups, which connected by a spacer. By this way, the separation approach between the polar headgroups within Gemini surfactants is strongly decreased when they aggregate and thus the surface activity is greatly enhanced. There are many papers related to the synthesis of anionic, cationic and nonionic Geminis, but few of literature is about the systematic studies on the zwitterionic surfactant. Until recently little work has been reported on Gemini zwitterionic phosphate surfactant. In this thesis, an exploring study was conducted on the synthesis and test performance of a new zwitterionic phosphate Gemini surfactant (named C₁₂GP).The preparation of the phosphate Gemini surfactant includes three steps. Firstly, the 1, 3-2chlorine-2-propyl alcohol was prepared by opening ring reaction of epoxy chloropropane with hydrochloric acid. Purification of reaction mixture was performed by reduced pressure and the yield was determined to be 96.5% above by GC. The structure of the aim product was analyzed and confirmed by the IR, refractive index and boiling point. Then the spacer group, the 2-(oxygen-prosphorusacyl-2 chlorine)-1, 3-2 chloropropane was prepared by esterification of phosphorus oxychloride and the l,3-dichlorine-2-propyl alcohol. Through optimizing the reaction conditions, the highest productivity could reach 98.6%. By analyzing the IR spectrum, the structure of the spacer group was confirmed. Finally, the phosphate zwitterionic Gemini surfactant C₁₂GP was synthesized with two molecules of Dodecyldimethylamine and the spacer group, 2-(oxygen-prosphorusacyl-2 chlorine)-1,3-2 chloropropane. The structure of the surfactant was also confirmed by analyzing the IR spectrum.The properties of the surfactant C₁₂GP were studied. It was indicated that at room temperature the surfactant can easily dissolved in water, and Krafft point is 0 ℃; the ultimate foaming height at the concentration of 1 × 10^-2 mol/L is 25 mm. Emulsifyingtest showed that the surfactant has super emulsifying ability and the value of HLB is 13-16. The lowest surface tension of the surfactant solution is 31.9 mN/m, C2o is 1.41xlO'5 mol/L, critical micelle concentration (CMC) is 1.4X10"4 mol/L, which demonstrated that the C^GP has high surface activity; and the isoelectric point of this zwitterionic compound is between pH 8.5 and pH 10.5. Lime soap dispering power is 50, much than sodium dodecyl benzene sulfonate. Detersive power is the same as the surfactant sodium dodecyl benzene sulfonate. The C12GP has good wetting power. The solubilization value for benzene in 0.2 mol/L surfactant solution is 1.6 XIO3 mL/mol. Synergism property of C12GP/SDS mixed system was studied. It is found that when the molar fraction of C12GP is about 0.2 in the mixed system, the surface activity shows a maximum. The experimental results also showed that surface tension of the mixture system was lower than those of single surfactant solutions, the minimum value being 27.4 mN/m at 25 °C. Addition of inorganic salts led to reduction of CMC too, but the effect was insignificant. Surface tension and critical micelle concentration of the mixture were determined. The influences of different inorganic salts, long and short chain alcohols on surface properties of C12GP/SDS mixed system were also studied.