苯胺双子衍生物在盐酸中对Q235碳钢的缓蚀性能

Corrosion inhibiting performances of aniline gemini derivative for Q235 carbon steel in hydrochloric acid

对苯胺及其双子衍生物1,3-二苯胺基异丙醇在1 mol/L盐酸中对碳钢的缓蚀性能进行了对比研究,探讨了通过双子衍生化提高有机分子缓蚀性能的有效性.静态失重法测得20℃下苯胺缓蚀率为85.15%～91.62%,而苯胺始终为82%左右.腐蚀动力学分析显示苯胺及其双子衍生物加入均能明显提高腐蚀反应势垒,阻碍腐蚀反应的发生,且双子衍生物阻碍效果更佳,表观活化能提高到48.94～59.59 k J/mol,高于苯胺的44.61～49.59 k J/mol.相同条件下双子衍生物缓蚀效果明显高于苯胺,原因是双子衍生化通过共价键连接拉近了两个N原子的距离,使分子中极性部位电荷密度增大,吸附能力增强,同时也使与N相连的疏水苯环距离更近,当形成吸附层时,其疏水层中苯环的密度也相应增大,阻隔效果更好.极化曲线测试结果表明,苯胺双子衍生物作为缓蚀剂可同时抑制阴阳极反应,属于混合型缓蚀剂.

To investigate the effect of gemini derivation on the corrosion inhibiting performances, the study of comparison between aniline and 1,3-bisphenylamino-isopropanol was conducted. At the temperature of20 ℃, the gemini derivative shows higher efficiency of 85.14%-91.62%, increasing with the concentration.While the aniline shows efficiency of around 82% regardless of the concentration. The energy barrier of corrosion reaction is enhanced both by aniline and the gemini derivative with the apparent activation energies of48.94-59.59 k J / mol for the gemini derivative, also higher than that of 44.61-49.59 k J / mol for aniline. The results show that the corrosion inhibiting performance of gemini derivative is obviously improved compared with that of aniline. It can be attributed to the closer distances between N atoms which were connected by covalent bonds. So the charge densities of the polar groups are elevated, and thus the adsorption ability is enhanced. With closer distances, the density of hydrophobic benzene rings is also increased, resulting in better blocking ability when forming the adsorption layer. The polarization curves show that the gemini derivative can be defined as a mixed type inhibitor that inhibits the anodic and cathodic reaction spontaneously.