十八烷基己基甲基羧基甜菜碱的合成及性能

Synthesis and Properties of Stearylhexylmethyl Carboxyl Betaine

以硬脂酸和己酸为原料合成了不对称双长链烷基羧基甜菜碱——十八烷基己基甲基羧基甜菜碱（C18＋6B）,测定了C18＋6B的表面活性,并与总碳原子数相等的对称型双十二烷基甲基羧基甜菜碱（di C12B）进行比较,以了解表面活性剂分子结构对性能的影响。结果表明,C18＋6B的表面活性与di C12B基本相当,但水溶性远好于di C12B。作为无碱驱油用表面活性剂,C18＋6B对大庆原油来说HLB值略偏高,45℃下单独使用能将大庆原油/地层水界面张力降至10^-2m N/m数量级,在大庆油砂上的饱和吸附量比di C12B低30%。C18＋6B单独能将C7-C9正构烷烃/大庆地层水界面张力降至10^-3m N/m数量级,而通过与亲油性更强的di C12B以及亲水性甜菜碱复配后,能将大庆原油/地层水界面张力降至10^-3m N/m数量级,并能显著改善配方的水溶性。

In order to gain insights into the effects of molecular structure on the properties of surfactants,an asymmetric double long-chain alkyl betaine,stearylhexylmethyl carboxyl betaine（ C18 ＋ 6B）,was synthesized using stearic acid and hexanoic acid as starting materials and its surface activity was measured and compared with that of didodecyl methyl carboxyl betaine（ di C12B）,a symmetric double long-chain betaine with equal total carbon number. The results show that C18 ＋ 6B has a surface activity similar to that of di C12 B in general,but displays an aqueous solubility much better than that of di C12 B. As a surfactant for surfactant-polymer flooding free of alkali,C18 ＋ 6B seems to be slightly less hydrophobic against Daqing crude oil,which solely can reduce the Daqing crude oil / connate water interfacial tension（ IFT） to 10^- 2m N / m magnitude and gives a saturated adsorption 30% lower than that of di C12 B at Daqing sandstone / water interface at 45 ℃. C18 ＋ 6B solely can reduce C7- C9 nalkanes / connate water IFT to 10^- 3m N / m magnitude at 45 ℃,and can reduce the Daqing crude oil /connate water IFT to 10- 3m N / m magnitude at 45 ℃ by mixing with the more hydrophobic surfactant di C12 B and other hydrophilic betaine surfactant,where the aqueous solubility of the formulation is greatly improved by the presence of C18 ＋ 6B.