A DFT STUDY OF N-ACETYLCYSTEINE AND D-PENICILLAMINE AS CORROSION INHIBITORS FOR COPPER

The most popular and accessible corrosion inhibitors, i.e., silicates, chromates, phosphates, nitrites, amines, and numerous formulations based on these compounds, are toxic and fail to produce a universal effect. Amino acids and their derivatives are non-toxic, relatively cheap, biodegradable compounds. These molecules can form a barrier through adsorption on the copper surface to reduce the corrosion, and it has been observed that the adsorption depends mainly on the coordination of bidentate ligands, which occurs through an amino or carboxyl group and thiol group -SH. In recent years, there has been considerable progress in the description of the structure and inhibition properties of corrosion inhibitors by using quantum chemical calculations. In this study, the molecular and electronic structures of N-acetylcysteine and D-penicillamine have been justified by comparing the theoretical data from the density functional theory (DFT) method with experimental corrosion inhibition efficiencies. The theoretical results were found to be consistent with the reported experimental data.