Synthesis of three imidazole derivatives and corrosion inhibition performance for copper

Abstract

Three imidazole derivatives, including 3-(4-(2,4-dichlorophenyl)-5-methyl-1H-imidazol-2-yl)pyridine (PDI), 2-(4-(2,4-dichlorophenyl)-5-methyl-1H-imidazol-2-yl)pyrazine (PAI) and 2-(4-(2,4-dichlorophenyl)-5-methyl-1H-imidazol-2-yl)pyrimidine (PMI), were synthesized. The structure of these compounds was confirmed by LC-MS, 1H NMR, 13C NMR and FTIR spectra. The inhibition performance in 3.5 wt% NaCl was investigated by electrochemical measurement and surface analysis. Results show that the corrosion efficiency of PDI (95.93%) was higher than PAI (69.61%) and PMI (20.46%), which is consistent with the adsorption energy calculated by molecular dynamics simulation. The corrosion inhibition mechanism could be explained by the metal–organic polymer film formed on the copper surface: on the one hand, the π-system formed by aromatic rings is tightly adsorbed on the copper substrates; on the other hand, the nitrogen atoms in the imidazole ring are coordinated with the metal ions in solution to form metal–organic polymer which could improve the compactness of the hydrophobic film.