| This thesis aimed to study the synthesis, characterization, basic interfacial properties and application in enhanced oil recovery of novel zwitterionic surfactant, di-decylmethyl betaine and di-dodecylmethyl betaine. It is showed that the target chemicals can be synthesized by reacting di-alkylmethyl amine with chloroacetic acid in the presence of NaOH. The reaction is a two phase reaction, which significantly affected by molar ratio of reactants, temperature and reaction time. An optimal reaction condition was obtained by orthogonal experiments, at which a conversion of tertiary amine higher than 80% can be achieved. The molecular structure of the synthesized product was characterized by elemental analysis, IR and Mass spectra, and was confirmed to be in good agreement with that of the target chemicals.The purified products display very high surface activities. At 25°C, both surfactants show a critical micelle concentration as low as 10-6 mol/L magnitude and aγcmc lower than 30mN/m. The saturated adsorption of the surfactants at air/water interface is so high that the cross section area of each molecule in the monolayer is 0.350.36 nm2, corresponding to a hydrocarbon chain cross section area of 0.170.18 nm2, which is much lower than that of sodium dodecyl sulfate, 0.5nm2. The di-alkylmethyl betaines have a good tolerance to electrolytes. In 0.1mol/L NaCl aqueous solution, the cmc of the di-dodecylmethyl betaine decreases a little, and in CaCl2 aqueous solutions at concentration up to 1600 mg/L, di-dodecylmethyl betaine can be well dissolved without visible precipitation. As a key surfactant, di-dodecylmethyl betaine has been successfully formulated to an oil displacements agent used for surfactant-polymer flooding. Without adding any alkaline chemicals or salts, the Daqing crude oil/water interfacial tension can reduce to lower than 1×10-2 mN/m in a total surfactant concentration range of 0.010.3%wt.% at 45°C, and a high tertiary oil recovery, 18%, was achieved.
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