Abstract

Two series of azomethine compounds derived from 2-hydroxy-3-methoxybenzaldehyde (o-vanillin) with 3-nitroaniline and p-toluidine were synthesized through condensation and characterized. The synthesized compounds were elucidated via elemental analysis (CHNS), nuclear magnetic resonance (NMR) spectroscopy, and infrared (IR) spectroscopy. The corrosion inhibitory effects of two azomethine compounds, namely 2-methoxy-6-((p-tolylimino)methyl)phenol (A3) and 2-methoxy-6-(((3-nitrophenyl)imino)methyl)phenol (A4) were studied on mild steel in 1 M hydrochloric acid (HCl) by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. Based on the electrochemical measurements, azomethine compounds A3 and A4 demonstrated good inhibition efficiency (87%) on mild steel in an acidic environment. The surface morphology of the mild steel specimen was further investigated by atomic force microscopy (AFM) and scanning electron microscopy (SEM).