Norfloxacin Skeleton-Included Dendritic Molecules as Corrosion Inhibitors on Mild Steel in Hydrochloric Acid: From Experiments to Molecular Dynamics Simulation

Abstract

In order to develop organic compounds for achieving highly efficient anticorrosion of mild steel in HCl solution, this study proposed to synthesize new dendritic molecules (DMs 1, 2) containing double norfloxacin skeletons. Besides, the linear molecule (LM) carrying a single norfloxacin framework was also prepared as the reference. The chemical structures of the studied molecules were fully characterized by nuclear magnetic resonance spectroscopy (1D and 2D NMR spectroscopy, 1H, 13C, 19F), mass spectroscopy (MS), Fourier-transform infrared spectroscopy (FT-IR). For this purpose, the adsorption of the studied molecules on mild steel was investigated by different means. Furthermore, the potential kinetic polarization and electrochemical impedance spectroscopy (EIS) were used to survey the anticorrosion of the studied molecules in HCl solution at 298 K. It is shown that the DMs displayed superior corrosion inhibition effect on mild steel over the LM in acid medium at 298 K (the maximal corrosion inhibition efficiency, LM, 87.80%, DM1, 96.00%, DM2, 96.26% at 0.015 mM). The anticorrosion and adsorption mechanisms of the studied molecules for mild steel were further understood by molecular modeling and adsorption isotherms.