Efficiency of a pyrimidine derivative for the corrosion inhibition of C1018 carbon steel in aqueous acidic medium: Experimental and theoretical approach

Abstract

The insoluble nature of many organic compounds restricts their application for the corrosion inhibition of metals in an aqueous acidic medium. To overcome this drawback, a new pyrimidine derivative, 5-acetyl-4-[4-(dimethylamino)phenyl]-6-methyl-3,4-dihydropyrimidin-2(1H)-one (ADP), has been designed and synthesized. Various electrochemical and theoretical methods were employed to evaluate the inhibition performance of ADP for the corrosion of C1018 carbon steel in aqueous 1.0 M HCl. The inhibition efficiency was 88.9% for 750 ppm of ADP. Tafel polarization curves revealed mixed-type inhibition of ADP. The current density was reduced with inhibitor ADP from 1110 to 123 μA/cm2 at 750 ppm. Electrochemical impedance spectral data showed increased polarization resistance from 12.6 to 84.3 Ώ/cm2 with the inhibitor concentration, increasing inhibition efficacy. The adsorption data of ADP fit appropriately to the Langmuir isotherm model. The surface analysis showed the development of the protective organic film that surrounded the defects that can shield chloride attack, hence preventing metal corrosion. Density functional theory and molecular dynamics simulation methods perfectly correlated with experimental inhibition performance.