Corrosion inhibition potential of new oxo-pyrimidine derivative on mild steel in acidic solution: Experimental and theoretical approaches

Abstract

Through electrochemical impedance testing and potentiodynamic polarisation, it was investigated how a material at ambient temperature might prevent corrosion. 1-(5-(4-Methoxybenzoyl)-4-(4-methoxyphenyl)-2-oxopyrimidin-1(2H)-yl)-3-(4-chlorophenyl) urea (MMOP) was used as a corrosion inhibitor on mild steel samples in 1 M HCl. With a maximum inhibition efficacy of 97.6 % (at immersion period of 72 h and concentration of 5 × 10-4 M), the inhibitor used was shown to be an exceptional corrosion inhibitor. Based on the findings of potentiometric polarization, this substance falls within the category of mixed inhibitors since corrosion inhibition was accomplished by the inhibitor adhering to the metal. Adsorption of investigated MMOP completely followed Langmuir adsorption isotherm and adsorption can be categorized as physisorption–chemisorption, with a value of ΔGads of -35.6 kJ.mol-1. In order to confirm the effectiveness of the protective coating applied to the mild steel surface, we analysed the protective layer through the utilization of Atomic Force Microscopy (AFM) and Scanning Electron Microscope (SEM) / Energy Dispersive X-ray spectrometry (EDX). The density functional theory (DFT) and Monte Carlo simulation (MCS) approaches were used to investigate the relationship between molecular structure and inhibitory efficacy. The results suggest that the inhibitor in issue could be a new approach to reducing mild steel corrosion under harsh circumstances and long immersion times.