Study On The Synthesis And Physicochemical Properties Of Novel Cationic And Zwitterionic Surfactants

The molecular design of oil -displacing surfactants is the researchful leading front in the field of enhanced oil recovery, and its key problem is the relationships between the molecular structures of the surfactants and their properties. The in-depth studies on this problem can provide the academic foundation for the expoitation of new type, high performance and economical oil-displacing surfactants.In the dissertation, two types of cationic and zwitterionic surfactants with hydroxy propyl have been synthesized and their properties have been studied. The experiments and results are as following:Eight straight (and branched) chain ammonium chloride cationics and glycine Betaine zwitterionics with high purity and definite structure were synthesized through several processes including short chain alpha-olefin dimerizing, anti-Markovnikov addition, glycidyl etherification, Williamson reaction and quaternization. Seven of those compounds never had been reported in the literature. The chemical structures of all products and main intermediates were characterized by IR, 1H-NMR and. ESI-MS.The di-substituted alpha-olefins with purity and definite structure were prepared by the dimerization of short chain alpha-olefin and the preparation of primary aliphatic bromide by the reaction of di-substituted alpha-olefins and gaseous hydrogen bromide was first studied .The effects of reaction variables(for example solvent, temperature and initiator etc.) upon conversion of alpha -olefin and the selectivity of primary aliphatic bromide were investigated. The results indicated that temperature in the range of -6～75C0 did not affect the conversion of alpha -olefin while markedly affected the selectivity of primary aliphatic bromide, which increased with the temperature decreasing; the solvent also had significantly effect upon the selectivity, and the nopolar solvent benefited the selectivity of primary aliphatic bromide.The effects of both hydrophobic structure and polyoxyethylene (EO) of straight (and branched) chain ammonium chloride cationics and glycine Betaine zwitterionics on interfacial properties were systematically investigated. The surface tensions of straight (and branched) chain ammonium chloride cationics and glycine Betaine zwitterionics were investigated by Wilhelmy plate method in aqueous solutin and in NaCl solutions. The values of critical micelle concentration (cmc), surface tension at cmc (γcmc), efficiency in surface tension reduction (pC20), saturation adsorption amount (Γm ax), standard free energy of adsorption (ΔGa0d), and of micellization (ΔGm0ic) were obtained by thermodynamic calculation fromγ?lgc curves. It was shown that all of those surfactants have the relatively low values of cmc (10-5-10-6mol/L ) andγcmc(25-34mN/m). In aqueous solution, the branching of the hydrophobic structure enhanced the surface activities, and theΓm ax decreased with polyoxyethylene (EO) added in molecular. These phenomena were reasonably explained by Blankschtein's theory based on two-dimensional gas model.The dynamic interfacial tensions between straight (or branched) long chain ammonium chloride cationics (and glycine Betaine zwitterionics) in NaCl solution (or Na2CO3 solution) and crude oil from Chendong shengli have been measured by spinning drop method. It was discovered that the super-lower interfacial tensions of the branched chain ammonium chloride cationics and glycine Betaine zwitterionics surfactants have been produced by a few addition of alkali(Na2CO3). Thus the branched chain ammonium chloride cationics and glycine Betaine zwitterionics surfactants may have a good prospect in the practical application.The relative contact angle and simulation oil recovery of the straight (and branched) long chain ammonium chloride cationics and glycine Betaine zwitterionics solution on the silicon gel powder have been obtained by Washburn method. The relationship between the relative contact angle and simulation oil recovery has also been discussed. The results indicated that the most change of wettability of these surfactants aqueous solution on silica gel powder appears near the cmc, and the best recovery of the laboratory model oil is also reached around the cmc. It proved that the wettability of the surfactant has a relationship with enhanced oil recovery.The foam properties of the straight (and branched) long chain ammonium chloride cationics and glycine Betaine zwitterionics in the aqueous solution under different physicochemical condition were measured by air flowing method. The results indicated that the branched chain ammonium chloride cationics surfactants showed good foaming ability. The foaming ability increased with the temperature increasing, while the foaming stability showed opposite tendency. The foaming stability of the straight (and branched) chain glycine Betaine zwitterionics increased with addition of NaCl, while the foaming ability was influenced little by addition of NaCl in our study.