Experimental and theoretical insights on the adsorption and inhibition mechanism of (2E)-2-(acetylamino)-3-(4-nitrophenyl) prop-2-enoic acid and 4-nitrobenzaldehyde on mild steel corrosion

Abstract: (2E)-2-(acetylamino)-3-(4-nitrophenyl)prop-2-enoic acid (NPP) was synthesized following a facile chemical method from 4-nitrobenzaldehyde (NB) and thoroughly characterized using spectroscopic techniques. These compounds were applied as novel inhibitors for corrosion of mild steel in 1M HCl using various methods such as absorbance difference, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). The results indicate that these inhibitors show an excellent protection performance and achieve the corrosion inhibition efficiency values of 94% and 84% for NPP and NB, respectively. The adsorption of these molecules obeys the El-Awady isotherm model. The surface analysis of mild steel was investigated using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) methods. Furthermore, quantum chemical calculations were investigated using DFT method at B3LYP/6-31G (d,p) computed by Gaussian 09 showing a good correlation with the experimental results. Graphic abstract: [Figure not available: see fulltext.] Synopsis A novel corrosion inhibitor namely 4-nitrobenzaldehyde derivative NPP was prepared and analyzed for mild steel in 1M HCl. The analysis were conducted by electrochemical, surface supported by DFT based reactivity parameters. NPP functioned by adsorption obeying the El-Awady isotherm and produced a high efficiency of 94%.