Abstract:

A series of fatty alcohol ether carboxylates （AEC） with narrow distribution （AEC₃/AEC₅/AEC₇/AEC₉） were synthesized by oxidation and using narrow distribution AEO （AEO₃/AEO₅/AEO₇/AEO₉）, oxygen and sodium hydroxide as raw materials. The process conditions of synthesis of narrow distribution AEC₇ （7EO units） were optimized. The surface tension, foaming performance and wettability of a series of narrow distribution AEC at different pH values were also investigated. The results show that： Given that the palladium carbon supported catalyst is in an amount corresponding to 0.4% of the mass of alcohol ether （by palladium chloride）, the optimized conditions to synthesize AEC₇ are as follows： the reaction temperature is 75 ℃, the oxygen pressure is 0.03 MPa, the rotating speed is 700 r/min, the molar ratio of narrow distribution AEO₇ to NaOH is 1∶1.02, and the yield thus obtained can reach 93.8%; The pH value has significant effects on the properties of AEC with narrow distribution. Among the AECs under investigation, the surface tension of AEC₇ being 41.66 mN/m is the highest compared with AEC₃/AEC₅/AEC₉ under neutral conditions; AEC₃ （3EO units） has the weakest foaming performance under acidic conditions and the strongest foaming performance under alkaline conditions; Among the narrow distribution AECs, AEC₃ has obvious advantages in wetting and surface tension compared with AEC₅/AEC₇/AEC₉ under neutral and alkaline conditions.

Key words: narrow distribution fatty alcohol ether carboxylate, oxidation, synthesis, performance