| Alkali-surfactant-polymer (ASP) flooding has been one of the useful tertiary oil recovery techniques in China. However, field tests in China have revealed that serious side effects may occur due to using alkali. Thus alkali-free SP flooding is more favorable in China. Unfortunately, surfactants effective in ASP flooding are usually ineffective in the absence of alkali and new surfactants need to be developed.In this paper the synthesis, characterization, basic interfacial properties and potential application in SP fooding of a novel anionic surfactant, N-(3-Oxapropanoxyl) dodecanamide, was studied. The target compound was synthesized by two rutes, as a pure compound synthesized by reaction of lauroyl chloride with diglycolamine in the presence of MgO and as a homologue mixture with narrow EO number distribution synthesized by addition of an ethylene oxide to coconut acid monoethanolamide (CMEA), respectively. The related fatty acid monoethanolamide can be synthesized by reaction of fatty acid methyl ester with monoethanol amine (MEA) in the presence of CH3ONa. Characterized by chemical analysis, thin layer liquid chromatograph (TLC), IR, Mass spectra and 1HNMR, the synthesized products were confirmed to have molecular structure of the target product.The products synthesized display both high surface activity and good application performances. At 45°C, they all show a critical micelle concentration as low as 10-610-5 mol/L and aγcmc lower than 28mN/m. The saturated adsorption of the surfactants at air/water interface are so high that the cross section area of each molecule in a monolayer at air/water interface is 0.290.36 nm2, which are much lower than that of sodium dodecyl sulfate, 0.5nm2. As a nonionic surfactant, N-(3-Oxapropanoxyl) dodecanamide displays good tolerance to electrolytes. It can be well dissolved without visible precipitation in an aquous solution of 2000 mg/L Ca2+ and the cmc of the N-(3-Oxapropanoxyl) dodecanamide is not sensitive to CaCl2 added. As a key surfactant, N-(3-Oxapropanoxyl) dodecanamide and its homologues have been successfully formulated to an oil displacement agent by which the Daqing crude oil/water interfacial tension can be reduced to 10-3 to 10-4 mN/m in a total surfactant concentration range of 0.010.5%wt.% at 45°C without adding any alkaline chemicals or salts, and a tertiary oil recovery as high as 18.6±0.4 % OOIP (original oil in place) can be achieved in oil displacement tests using nature cores.
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