Electrochemical Corrosion Performance of Aromatic Functionalized Imidazole Inhibitor Under Hydrodynamic Conditions on API X65 Carbon Steel in 1 M HCl Solution

The hydrodynamic corrosion inhibitive performance of two imidazole derivatives 2-ethyl-4-methylimidazole and 1-benzylimidazole was investigated on API X65 steel in 1.0 M HCl solution. Structural features of the molecules derived from density functional theory (DFT) calculations at B3LYP/6-31G(d.p) showed that 1-benzylimidazole possess high electron density due to π network which lies flat on the surface and tends to form a stronger interaction with the metal. The addition of the inhibitor molecules in 1 M HCl solution shifted the corrosion potential (E_corr) in the noble direction. Tafel polarization and electrochemical impedance spectroscopy (EIS) experiments performed at 0–1500 rpm and 50–500 ppm of inhibitor concentration revealed that the corrosion rate was increased with an increase in rotation speed in the absence of inhibitor molecules. However, upon the addition of the inhibitor molecules in the solution minimized the corrosion rate with an efficiency of 82% in the case of 1-benzylimidazole at 500 ppm and 500 rpm electrode rotation. It was concluded that simple imidazole molecules could serve as corrosion inhibitors under extreme hydrodynamic conditions.