Abstract: Oleyl monoethanolamide was synthesized by oleic acid and monoethanolamine through two steps.Then the oleyl monoethanolamide was stepwise phosphorylated and quarternarized with phosphorus oxychloride and cetyl dimethyl amine to synthesis of the product zwitterionic Gemini surfactant.Acid value and amine value were used as examination indices for synthesis conditions of oleyl monoethanolamide.Based on single factor tests results the suitable conditions were identified as:1 mol oleic acid and 0.8 mol monoethanolamine reacts at temperature of 160 ℃ for 5 h;then reduce the temperature to 80 ℃ and make up 0.25 mol of monoethanolamine for 3 h.The suitable preparing conditions for the product zwitterionic Gemini surfactant using emulsifying power and wetting power as examination indices were identified as:1 mol oleyl monoethanolamide and 0.7 mol POCl₃ reacts under temperature of 0 ℃ for 4 h;then 0.75 mol cetyl dimethyl amine is added at 65 ℃ for 18 h.The cmc of the product Gemini surfactant is 7.88×10^-4 mol/L;stable time of emulsified liquid achieves 680 s;wetting time is 35 s.

Key words: zwitterionic Gemini surfactant, oleic acid, phosphorylation, quarternarization