Abstract:

Dodecylamine polyoxyethylene ether （DAEO₅） was synthesized by ethoxylation of dodecyl amine with ethylene oxide （EO） using catalysts KOH, SnCl₄, and a weakly basic heterogeneous catalyst （NHGC） made by our laboratory. The total EO number in the molecular structure of DAEO₅ was 5. According to the literature, the type of catalysts directly affects the molecular weight distribution of the product. Therefore, those DAEO₅ products prepared with different catalytic systems were analyzed, as well as their molecular weight distribution, surface tension of aqueous solutions, physicochemical properties, and application performance. The results showed that, the DAEO₅ prepared with NHGC had narrower distribution and lower content of free amine than those prepared with conventional catalysts of ethoxylation, and its viscosity and cloud point in aqueous solution were higher than those of other products. The ∆G_mic and ∆G_mic of DAEO₅ synthesized using different catalytic systems were all negative, indicating that DAEO₅ could spontaneously form micelles and adsorption layer in water. The wetting and emulsifying properties of the product synthesized with NHGC were better, and its wetting time was much shorter than those products synthesized using KOH and SnCl₄ as catalysts. The detergency of products synthesized with different catalysts did not differ much, but their detergency was different for carbon black stained cloth and sebum stained cloth, which was significantly better for carbon black stained cloth than for sebum stained cloth.

Key words: fatty amine, ethoxylation, narrow distribution, physical and chemical properties, application property