Studies On Synthesis And Properties Of Gemini Surfactants

Gemini surfactant is a significant breakthrough of improving surface activity, breaking a new path for practical application with wide business foreground. After its cost is reduced, Gemini surfactants will take the place of conventional surfactants in many fields.We make the general and detailed review about Gemini surfactants in this paper, and analyze the problem in Gemini surfactants' research. We also put forward the ideas and routes for our study. The main contents and results of investigations are as follows:1. A series of cationic Gemini surfactants with dodecyl, tetradecyl and hexadecyl hydrocarbonic chains in hydrophobic groups were synthesized by a one-pot convenient method using longchain alkylamine, hydrochloride and epichlohydnn. At the same time, we synthesized the same products with longchain alkylamine and l,3-dichloro-2-propanol. Its structure was characterized by IR, ~1H-NMR and elmements analysis.2. By orthogonal examination we got the optimum process condition of synthesizing cationic dodecyl Geminis: (1) Molar ratio of N, N-dimethyldodecyl amine, hydrochloride and epichlohydrin was 2.2:1.1:1.0; epichlohydnn was added after complete reaction of N, N-dimethyldodecylamine and hydrochloride, then refluxing for 16h in ethanol solution. (2) Molar ratio of N, N-dimethyldodecylamine and l,3-dichloro-2-propanol was 2.4:1.0, refluxing for 30h in propane solution. Results indicated that the former method is prior to the latter. Compared with the method reported in literature, we shortened reaction time and predigested operation flow apparently.3. The hydroxyl of Geminis was sulfonated by chlorosulfonic acid, then neutralized by sodium hydroxide to afford zwitterionic Gemini surfactants with three-head groups and two-hydrophobic chains. Its structure was characterized by IR, MS and elmements analysis.4. The optimum reaction condition of synthesizing zwitterionic Geminis was investigated through orthogonal examination. The optimal molar ratio of Gemini and chlorosulfonic acid is 1.0:1.3, and the reaction time is 4 hours at the temperature of 30 ℃.5. Critical micelle concentration (CMC) and surface tension (γ cmc) wereinvestigated by the ring method. Experiment results indicated that surface activity of the novel zwitterionic Gemini surfactants is excellent. We also investigated the properties of two-serier Gemini surfactants, such as solubility, emulsification, enhancing dissolution, hard water resistance and reduced viscosity at different temperature. In the end, the application in Enhanced Oil Recovery and other fields was forecasted.