Experimental and computational chemistry investigation of the molecular structures of new synthetic quinazolinone derivatives as acid corrosion inhibitors for mild steel

Abstract

Two new organic compounds, namely, 3-(2-(2-chloroethoxy)ethyl)-2-phenylquinazolin-4(3H)-one (QZ-H) and 3-(2-(2-chloroethoxy)ethyl)-2-(4-chlorophenyl)quinazolin-4(3H)-one (QZ-Cl) were synthesized based on quinazolinone derivatives, and their chemical structures were identified using non-instrumental analytical methods such as proton and carbon nuclear magnetic resonance (1H NMR and 13C NMR). After successfully synthesizing and spectrally characterization, they were tested for mild steel protection in 1.0 M HCl medium. In addition, their anticorrosion characters and molecular structure-activity relationship were evaluated using the classical electrochemical and theoretical methods, respectively. Experimental studies showed that these compounds are good corrosion inhibitors, where their inhibition efficiencies increase with their concentrations to reach a maximum of 87.75 % and 88.76 % at 10−3 M of QZ-H and QZ-Cl, respectively. It is also found that these products react as mixed-type inhibitors. In addition, the estimated activation parameters indicate that the dissolution process of mild steel is endothermic and the products act via physical adsorption on metallic surface according to the Langmuir isotherm. Finally, the theoretical studies using DFT calculations and MD simulations authorize the experimental results and the order of inhibition efficiency.