Fouda Abd El-Aziz S, El-Askalany Abdelmonem H, Molouk Ahmed F S, Elsheikh Niveen S, Abousalem Ashraf S
Chemistry Department, Faculty of Science, Mansoura University, El-Mansoura, Egypt.
Quality Control Laboratory, Operations Department, JOTUN, Cairo, Egypt.
Sci Rep. 2021 Nov 4;11(1):21672. doi: 10.1038/s41598-021-00701-z.
The present work aims to study 6-amino-4-aryl-2-oxo-1-phenyl-1,2-dihydropyridine-3,5-dicarbonitrile derivatives namely: 6-Amino-2-oxo-1,4-diphenyl-1,2-dihydropyridine-3,5-dicarbonitrile (PdC-H), 6-Amino-2-oxo-1-phenyl-4-(p-tolyl)-1,2-dihydropyridine-3,5-dicarbonitrile (PdC-Me) and 6-Amino-4-(4-hydroxyphenyl)-2-oxo-1-phenyl-1,2-dihydropyridine-3,5-dicarbonitrile (PdC-OH) as corrosion inhibitors to provide protection for carbon steel in a molar hydrochloric acid medium. Chemical measurements such as (weight loss) and electrochemical techniques such as (Potentiodynamic polarization, electrochemical impedance spectroscopy, and Electron frequency modulation) were applied to characterize the inhibitory properties of the synthesized derivatives. The adsorption of these derivatives on the carbon steel surface was confirmed by Attenuated Total Refraction Infrared (ATR-IR), Atomic Force Microscope (AFM), and X-ray Photoelectron Spectroscopy (XPS). Our findings revealed that the tested derivatives have corrosion inhibition power, which increased significantly from 75.7 to 91.67% on the addition of KI (PdC-OH:KI = 1:1) to inhibited test solution with PdC-OH derivative at 25 °C. The adsorption process on the metal surface follows the Langmuir adsorption model. XPS analysis showed that the inhibitor layer consists of an iron oxide/hydroxide mixture in which the inhibitor molecules are incorporated. Computational chemical theories such as DFT calculations and Mont Carlo simulation have been performed to correlate the molecular properties of the investigated inhibitors with experimental efficiency. The theoretical speculation by Dmol3 corroborates with the results from the experimental findings.
本研究旨在探究6-氨基-4-芳基-2-氧代-1-苯基-1,2-二氢吡啶-3,5-二甲腈衍生物，即：6-氨基-2-氧代-1,4-二苯基-1,2-二氢吡啶-3,5-二甲腈（PdC-H）、6-氨基-2-氧代-1-苯基-4-（对甲苯基）-1,2-二氢吡啶-3,5-二甲腈（PdC-Me）和6-氨基-4-（4-羟基苯基）-2-氧代-1-苯基-1,2-二氢吡啶-3,5-二甲腈（PdC-OH）作为缓蚀剂，在摩尔盐酸介质中对碳钢的保护作用。采用化学测量方法（如失重法）和电化学技术（如动电位极化、电化学阻抗谱和电子频率调制）来表征合成衍生物的缓蚀性能。通过衰减全反射红外光谱（ATR-IR）、原子力显微镜（AFM）和X射线光电子能谱（XPS）证实了这些衍生物在碳钢表面的吸附。我们的研究结果表明，所测试的衍生物具有缓蚀能力，在25℃下，向含有PdC-OH衍生物的测试溶液中加入KI（PdC-OH:KI = 1:1）后，缓蚀率从75.7%显著提高到91.67%。金属表面的吸附过程遵循朗缪尔吸附模型。XPS分析表明，缓蚀剂层由掺入了缓蚀剂分子的氧化铁/氢氧化铁混合物组成。进行了密度泛函理论（DFT）计算和蒙特卡罗模拟等计算化学理论，以关联所研究缓蚀剂的分子性质与实验效率。Dmol3的理论推测与实验结果相符。
