Multicomponent synthesis and designing of tetrasubstituted imidazole compounds catalyzed via ionic-liquid for acid steel corrosion protection: Experimental exploration and theoretical calculations

Five new tetrasubstituted imidazoles were designed with outstanding yields (83%−92%) in the occurrence of ionic liquid-based-pyridinium as a catalyst. The constructions of all synthesized derivatives were established by spectral tools and their purities were verified using thin-layer chromatography (TLC), displaying single-spot. The performance of corrosion protection of the prepared imidazole derivatives was examined theoretically and practically for acid steel corrosion. The experimental study was conducted by electrochemical (electrochemical impedance spectroscopy (EIS) and Tafel polarization (PPS)) tools. The findings from the used approaches concluded that the synthesized compounds were well-organized inhibitors with an efficiency of 90.7%−98.5% at 50 °C and 0.7 mmol·L⁻¹. The Tafel polarization results indicate the protective action of the additives was under mixed-monitoring. The additive adsorption on the electrode interface performed as a distinguished aspect for protection. The surface exploration on the blank and protected metal was completed by field emission scanning electron microscopy (FE-SEM). Computational studies by Monte Carlo (MC) simulation and quantum chemical calculation (DFT) were related to practical findings. The corrosion protection adsorption mechanism was reinforced by the preferable fitted Langmuir isotherm model. All findings from the applied-inspected approaches alternately confirm each other.