Insight into Corrosion Inhibition Efficiency of Imidazole-Based Molecules: A Quantum Chemical Study

Quantum chemical calculations utilizing DFT at 6-311++G(d,p) basis set in gaseous and aqueous phases for protonated and non-protonated species were conducted. To evaluate corrosion inhibition efficiency, four compounds, namely 4-methyl-5-hydroxymethylimidazole (MHI), benzimidazole (BI), 2‑amino BI (ABI), 2-hydroxymethyl-BI (HMB), imidazole (I), 2-methyl BI (MBI), 5-methyl-imidazole (MI), and 4-(1H-imidazol-1-yl) phenol (PHEN) were compared. Several considered chemical parameters were calculated such as HOMO, LUMO, Δ Eg , dipole moment, ionization energy, electron affinity, hardness ( η ), softness ( σ ), electrophilicity, nucleophilicity, electron transfer ( Δ N ), and back-donation energy (ΔEb-d). Using a molecular dynamic modeling method, the adsorption behaviors of the researched chemicals on the Fe (1 1 0) surface were examined. The corrosion inhibition efficiency ranking followed the order PHEN > MBI > ABI > MHBI > BI > MHI > MI > I. It should be observed that the study’s findings are in strong accord with previously published findings on experimental inhibition efficiency.