Assessment of quinazoline derivatives as efficient corrosion inhibitor for carbon steel in acidic environment. A theoretical and practical analysis

Three quinazoline derivatives namely, 2-methylquinazoline (Q I ), 1-amino-2-methylquinazolin-4(1H)-one (Q II ) and (E)-2-styrylquinazolin-4-ol (Q III ) were evaluated for their capability to inhibit carbon steel (CSt) corrosion in a 0.5 M H₂SO₄ solution using chemical, electrochemical, and quantum computation methods. Density functional theory (DFT), Fukui function analysis, and Monte Carlo simulations (MCS) were employed to evaluate the corrosion inhibition efficiency of three quinazoline derivatives (Q I , Q II , and Q III ) on the Fe(110) surface. The findings demonstrate that the inhibition efficiency (%Ƞ) from all methods applied rises as quinazoline derivative concentrations rise and falls with increasing temperature. The values of %Ƞ for Q I , Q II , and Q III using PDP methods was 94.81%, 95.32%, and 96.15% at 1×10⁻³M, respectively. The results demonstrate that the %Ƞ from all methods used rises as quinazoline derivative concentrations rise and falls with increasing temperature. PDP results confirm that quinazoline derivatives are a mixed inhibitor. The inhibition abilities of these derivatives were deduced from their potent adsorption on the CSt surface as demonstrated by the Langmuir isotherm. Quinazoline derivatives operated as efficient pitting inhibitors by transforming the pitting potential to the noble trends. All employed methods confirm that the % IE for Q III > Q II > Q I . DFT and MCS calculations reveal Q III as the most effective inhibitor that agrees with experimental results.