Corrosion inhibition performance of mild steel in HCl solution by new organic imidazopyridine-based inhibitors

Abstract

• Two new imidazopyridine-based Schiff base compounds, IMP 01 and IMP 02 , were synthesized by simple, low-cost methods. • The synthesized IMP 01–02 ligands were characterized by various spectroscopic techniques (NMR, FT-IR and LC-MS) to confirm their chemical structure . • Both IMP 01–02 inhibitors showed significant efficacy against mild steel corrosion in an acid medium (1 M HCl), with maximum efficacy of 96 % for IMP 01 . • Surface visualization by SEM-EDX, together with theoretical simulations (DFT and MD) confirmed the inhibitory behavior and supported the adsorption mechanism of the compounds. The current research involves the development and preparation of two novel, non-toxic imidazopyridine-based Schiff base inhibitors, IMP 01 and IMP 02 , using simple, cost-effective, and environmentally friendly methods. Characterization of the two compounds was carried out using advanced analytical techniques such as NMR (1H and 13C), FT-IR spectroscopy and LC-MS chromatography. The effectiveness of IMP 01 and IMP 02 as corrosion inhibitors for mild steel in 1 M HCl solution was evaluated through electrochemical methods at various temperatures and concentrations. The results demonstrate that both inhibitors provide significant corrosion protection. The consistency between potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) measurements showed inhibition efficiencies of 96 % for IMP 01 and 85 % for IMP 02 . Both inhibitors exhibited a mixed cathodic and anodic behavior, following the Langmuir adsorption model. Scanning Electron Microscopy (SEM) analysis of the steel surface revealed minimal degradation in the presence of IMP 01 and IMP 02 , particularly with IMP 01 . Additionally, theoretical studies, including density functional theory (DFT) and molecular dynamics (MD) simulations, supported the proposed inhibition mechanism.