2024/09/17 by Errahmany, N., El Kafssaoui, E. H., Touir, R. +9
paper · doi:10.48317/imist.prsm/morjchem-v12i4.50566
The study involved the synthesis and characterization of two hydrazinylidene-based quinoxaline derivatives, namely (2E,3E)-2,3-dihydrazono-6,7-dimethyl-1,2,3,4-tetrahydroquinoxaline (QN-CH3) and (2E,3E)-6-chloro-2,3-dihydrazono-1,2,3,4-tetrahydroquinoxaline (QN-Cl). These derivatives were tested for their effectiveness as inhibitors for mild steel in a 1.0 M hydrochloric acid solution at 363 K using various methods such as electrochemical tests, surface analysis techniques like scanning electron microscopy (SEM), as well as density functional theory (DFT) and molecular dynamics (MD) simulation. It was observed from the current-potential (I-E) curves that both QN-CH3 and QN-Cl acted as cathodic-type inhibitors, with their inhibition efficiencies increasing with concentration. At a concentration of 10-3 M, the inhibition efficiencies reached a maximum of 89.07% for QN-CH3 and 87.64% for QN-Cl. Electrochemical impedance spectroscopy (EIS) tests pointed towards the corrosion process being controlled by charge transfer. The superior performance of QN-CH3 compared to QN-Cl was attributed to the nature of its molecular structure. Furthermore, it was found that the hydrazinylidene-based quinoxaline derivatives adhered to the mild steel surface according to the Langmuir isotherm and maintained their anticorrosion performance at high temperatures, as confirmed by SEM analysis. DFT calculations and MD simulations provided further insight into the corrosion inhibition mechanism.