Electrochemical and Theoretical Study of the Corrosion Inhibition of Carbon Steel Using 3-Allyl-2-mercaptoquinazolin-4(3H)-one in an Acidic Environment

This study investigates the corrosion inhibition performance of a newly synthesized quinazolinone derivative, AMQ, on mild steel in a hydrochloric acid medium. The inhibition efficiency was evaluated using potentiodynamic polarization at varying inhibitor concentrations (100–250 ppm) and temperatures (303–333 K). The results showed that AMQ exhibited effective corrosion inhibition, with the highest efficiency of 74% observed at 250 ppm and 323 K. Density Functional Theory (DFT) calculations were conducted to study the electronic properties of AMQ and its adsorption behavior. The thermodynamic parameters, including activation energy, enthalpy, and Gibbs free energy, were calculated, indicating spontaneous adsorption of AMQ onto the metal surface, primarily through physisorption. Additionally, the adsorption isotherm confirmed the Langmuir adsorption mechanism. This combined experimental and theoretical study provides insights into the inhibitory action of AMQ and highlights its potential as an efficient corrosion inhibitor.