Synthesis And Properties Of The Amido Modified Carboxylate Surfactants

According to the requirement of foaming system used in oil recovering and literature research, two series of amido modification phthalic single amide carboxylic acid and leoyl single amide carboxylic acid surfactants were designed and synthesized with the materials of anhydride and alkyl amine. In this paper, low carbon phthalic anhydride and maleic anhydride were used as the materials react with long-chain alkyl amine(Stearic amine,palmitic amine,myristic amine,lauryl amine), it has the advantage of low cost and simple process.According to the yield,the effect of dissolvant,reaction temperature, reaction time and material ratio on reaction was discussed, the optimum synthetic conditions was determinated,which for phthalic single amide carboxylic acid are: phthalic anhydride / alkyl amine (mol ratio)=1.1:1,reaction temperature 35℃,reaction time 15 minutes,under the solvent of dichloromethane, yieid above 80%;for leoyl single amide carboxylic acid are: maleic anhydride/alkyl amine (mol ratio)=1.1:1,reaction temperature 35℃,reaction time 15 minutes,under the solvent of chloroform,yieid above 80%. The method of purifying was researched.Recrystallizition showed good result. The resolution of purity analyses of the produts by HPLC were studied. The result showed the purity of all the products after recrystallizition could achieve 95%. The structure of products were identified by IR,1H NMR correspondingly.For the different carbon chains and structure products, the foam performance, oil-water interfacial tension and surface tension were tested. The effeets of oleophilic group structures of surfactants on the surfacial and interfacial tensions were diseussed. Expect that it can provide basic theoretical evidences and practical value for the surfactants applied in oil recovering.In the condition of distilled water and Daqing oil field, the foam performance was compared. Mleoyl single amido acid salts match Daqing Oil field well. The FCI was up to 300000, showing excellent propertie of slt resistance.Aming at present condition of Daqing oil field, the oil-water interfacial tension was researched. The phthalic single stearic amido acid salts, phthalic single myristic amido acid salts, Mleoyl single stearic amido acid salts have excellent properties of oil-water interfacial tension. They can reach 2.16×10_-3 mN·m_-1,4.25×10_-3 mN·m_-1,4.02×10_-3 mN·m-1 at the optimum conditions. It turned out that in the same series of the products, when the hydrophobe alkyl carbon atoms were different, a long carbon chain had a better capacity to reduce the oil-water interfacial tension than the short one.The surface tension and CMC were tested at 25℃. The saturation adsorption values, at the air/water interface and the minimum area per surfactant molecule, standard free energy of micellizationand,standard free energy of adsorption of the products and the efficiency that thesurfactants reduce the surface tension pC₂0 were obtained from the slope of the surface tension versus log concentration plots by using the approximate form of the Gibbs adsorption isotherm equations.The surface tension of products changes between 30.34～38.24mN·m_-1, show that they are highly effective aqueous surfactants. The pC₂0 value is between 3.88～4.85, show that they can significantly reduce the surface tension of the solution at low concentration. TheΔG^o_mic values are negatives, indicate that they are autogentic processes.The surface properties of the products acquired in this paper are important parameters for the products applied in other fields.