Theoretical investigation of the performance of benzimidazole derivatives as mild steel organic corrosion inhibitors in acidic environments

The efficiency of various benzimidazole derivatives as mild steel corrosion inhibitors in HCl and H2SO4 medium was evaluated using quantum chemical methods. The AM1 semi-empirical method and Density Functional Theory (DFT) at the B3LYP/6-31G* level were used. The orbital energies (EHOMO and ELUMO), Separation Energy (ELUMO-EHOMO), Dipole moment (µ), Log P, Polarizability, molecular volume, molecular weight, Hardness (η) and Softness (S) are the computed quantum chemical characteristics linked to inhibitory efficiency. There was a strong link between quantum chemical parameters and experimental inhibition efficiency. The findings revealed that the Inhibition Efficiency was linked to a number of quantum chemical factors. The 2-mercaptobenzimidazole derivative had a higher Inhibition Efficiency (IE) than the other benzimidazole derivatives, according to the results.