新型不对称双季铵盐表面活性剂的制备及缓蚀性能

Preparation and corrosion inhibition performance of new asymmetric double quaternary ammonium salt surfactant

本文以十二烷基二甲基叔胺、十六烷基二甲基叔胺、氯乙酰氯和1,3-丙二胺为原料,通过三步法制得一种新型高效、环境友好的不对称双季铵盐表面活性剂,研究了其在1 mol/L盐酸溶液中对2024 Al-Cu-Mg合金表面的缓蚀性能和机理。通过红外光谱和核磁共振氢谱对其结构进行表征;通过表面张力获得其临界胶束浓度(CMC);利用静态挂片失重法和电化学方法研究了其对2024铝合金的缓蚀性能。实验结果表明:其CMC为2.0×10^(-3) mol/L;当其浓度为CMC时缓蚀效率最高,可达94.9%,缓蚀效率随浓度增加而增加;当浓度小于CMC时其在2024 Al-Cu-Mg合金表面的吸附自由能为-30.84 kJ/mol,遵循Langmuir吸附等温线。阐明了其作用于合金表面的吸附为单分子层吸附,更倾向于物理吸附。

Dodecyl dimethyl tertiary amine,hexadecyl dimethyl tertiary amine,chloroacetyl chloride,and 1,3-propanediamine were used as raw materials to prepare a new type of asymmetric double quaternary ammonium salt surfactant with high efficiency and environmental friendliness through a three-step method.The corrosion inhibition performance and mechanism of the new surfactant on the surface of 2024 Al-Cu-Mg alloy in 1 mol/L hydrochloric acid solution were studied.The structure was characterized by infrared spectroscopy(IR)and nuclear magnetic resonance(NMR),the critical micelle concentration(CMC)of the product was obtained by surface tension,and the corrosion inhibition performance was analyzed by static weight loss method and electrochemical method.Results show that the CMC of the new surfactant was 2.0×10^(-3) mol/L,under which the corrosion inhibition efficiency was the highest and up to 94.9%.The corrosion inhibition efficiency increased with the increase of the concentration.The free energy of adsorption on the surface of 2024 Al-Cu-Mg alloy was-30.84 kJ/mol,according with the Langmuir adsorption isotherm.It clarified that the adsorption of the new surfactant on the alloy surface was monolayer adsorption,more inclined to physical adsorption.