Unidad Anticorrosión, Instituto de Ingeniería, Universidad Veracruzana, Boca del Río, Veracruz 94292, Mexico.
Departamento de Ingeniería Metalúrgica, Facultad de Química, Universidad Nacional Autónoma de México, Av. Universidad No. 3000, Coyoacán, C.U., Ciudad de México 04510, Mexico.
Int J Mol Sci. 2022 Mar 15;23(6):3130. doi: 10.3390/ijms23063130.
The corrosion inhibition of 5--β--glucopyranosyl-7-methoxy-3',4'-dihydroxy-4-phenylcoumarin (4-PC) in AISI 1018 steel immersed in 3% NaCl + CO was studied by electrochemical impedance spectroscopy (EIS). The results showed that, at just 10 ppm, 4-PC exerted protection against corrosion with = 90% and 97% at 100 rpm. At static conditions, the polarization curves indicated that, at 5 ppm, the inhibitor presented anodic behavior, while at 10 and 50 ppm, there was a cathodic-type inhibitor. The inhibitor adsorption was demonstrated to be chemisorption, according to the Langmuir isotherm for 100 and 500 rpm. By means of SEM-EDS, the corrosion inhibition was demonstrated, as well as the fact that the organic compound was effective for up to 72 h of immersion. At static conditions, dispersion-corrected density functional theory results reveal that the chemical bonds established by the phenyl group of 4-PC are responsible of the chemisorption on the steel surface. According with Fukui reactivity indices, the molecules adsorbed on the metal surface provide a protective cover against nucleophilic and electrophilic attacks, pointing to the corrosion inhibition properties of 4-PC.
5-β--吡喃葡萄糖基-7-甲氧基-3',4'-二羟基-4-苯基香豆素（4-PC）在 AISI 1018 钢中浸入 3%NaCl+CO 中的腐蚀抑制作用通过电化学阻抗谱（EIS）进行了研究。结果表明，在 10ppm 时，4-PC 在 100rpm 下对腐蚀的保护效率达到了 90%和 97%。在静态条件下，极化曲线表明，在 5ppm 时，抑制剂呈现出阳极行为，而在 10ppm 和 50ppm 时，抑制剂呈现出阴极型。根据 100 和 500rpm 下的 Langmuir 等温线，证明了抑制剂的吸附是化学吸附。通过 SEM-EDS，证明了腐蚀抑制作用，并且该有机化合物在浸泡 72 小时内有效。在静态条件下，修正后的密度泛函理论结果表明，4-PC 的苯基基团建立的化学键是其在钢表面发生化学吸附的原因。根据 Fukui 反应性指数，吸附在金属表面的分子提供了对亲核和亲电攻击的保护覆盖，这表明 4-PC 具有腐蚀抑制性能。
