Experimental and Computational Studies of N-(4,6-Dimethylpyrimidin-2-yl)-4-[(quinazoline-4-yl)amino]-benzene-1-sulfonamide as an Effectual Corrosion Inhibitor for Mild Steel in Hydrochloric Acid

Abstract

Abstract: The inhibition efficacy of N-(4,6-dimethylpyrimidin-2-yl)-4-[(quinazoline-4-yl)amino]benzene-1-sulfonamide (DMQS) as a new corrosion inhibitor on mild steel (MS) in 0.1 M HCl medium at varied temperature has been analysed and it has ensued 97.6% high efficiency at 4 × 10–5 M of DMQS. The electrochemical techniques employed were impedance spectroscopy and potentiodynamic polarization. Surface analysis of MS was carried out through scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS). Inhibitory effect of DMQS escalated with elevated concentration and declined with elevation in solution temperature. The adsorption of DMQS on MS has consent with the Langmuir adsorption isotherm. The computational study using density functional theory (DFT) with the B3LYP/3-21G basis set level for DMQS was investigated through the association between their molecular and electronic structure. The parameters involved in quantum chemical calculations were energy gap, E<inf>HOMO</inf>, E<inf>LUMO</inf>, absolute electronegativity, electrophilicity, softness, global hardness, energy gap, ionisation energy, electron affinity and dipole moment. DMQS shows E<inf>HOMO</inf> value of –6.256 eV, fortifying MS from corrosive attack and implicating it to be an effectual inhibitor. The results of the implemented studies show the corrosion inhibition efficiency of the DMQS is in good accord. © 2021, Pleiades Publishing, Ltd.