One-pot synthesis of novel triphenyl hexyl imidazole derivatives catalyzed by ionic liquid for acid corrosion inhibition of C1018 steel: Experimental and computational perspectives

Five novel triphenyl hexyl imidazole derivatives were synthesized with excellent yields (78–91%) in the presence of pyridinium-based ionic liquid as catalyst. The structures of all designed compounds were confirmed through spectral methods and their purity were tested by means of thin-layer chromatography, showing one-spot. The adsorption performance and inhibitive action of imidazole compounds on the C1018 steel alloy corrosion in molar HCl medium at 323 K were examined. The applied approaches were electrochemical trainings (electrochemical impedance spectroscopy [EIS], potentiodynamic polarization [PDP], linear polarization resistance [LPR] corrosion rate, and potential vs. time), and surface examination (field emission scanning electron microscopy [FESEM]). The findings analysis exhibited that the protection capacity augmented with increasing the additive dose to reach 89.6–98.1% with 2.0 × 10⁻³ mol/L of imidazole derivatives. PDP profiles designated that the imidazole derivatives perform as mixed-kind inhibitors. The triphenyl hexyl imidazole molecules were adsorbed at the interface of C1018 steel/HCl following the Langmuir isotherm model. The free energy of adsorption process values showed a competitive chemical and physical adsorption of prepared imidazole compounds on the C1018 steel interface. The outcomes from the potential of zero charge (E_pzc) investigations support the above interpretations. The FESEM analysis of the corroded C1018 steel in the absence and presence of studied imidazole inhibitors evidently exhibited different findings. Furthermore, the relation between the protection abilities and the structure of inhibitors molecules was discussed by applying the theoretical study of density function theory (DFT) and Monte Carlo (MC) simulations.