New N-Heterocyclic Compounds Based on 8-Hydroxyquinoline as Efficient Corrosion Inhibition for Mild Steel in HCl Solution: Experimental and Theoretical Assessments

초록

Both new benzimidazole derivatives based on 8-hydroxyquinoline, namely 4-(1-((4-hydroxynaphthalen-1-yl)methyl)-5-methyl-1H-benzo[d]imidazol-2-yl)benzoic acid (QN1) and 4-(1-((4-hydroxynaphthalen-1-yl)methyl)-1H-benzo[d]imidazol-2-yl)benzoic acid (QN2), were synthesized and characterized, and their corrosion inhibition behavior as well as the mechanism of inhibition was investigated by different techniques. Structural characterization includes NMR, IR and elemental analysis. The anticorrosive activity of these compounds was evaluated by the potentiodynamic polarization and impedance spectroscopy. Experimental data show that the QN1 and QN2 are effective against corrosion of steel in 1.0 M HCl and that the inhibitory efficiency reached at an optimum value of 97.7% for the QN1 compound at 1 mm. Polarization Tafel curves show that QN11 and QN2 act as a mixed type of inhibitors. After evaluating the anticorrosive activity of these two compounds, we used the surface techniques, namely SEM coupled with EDS and the gravimetric solutions were analyzed by UV–visible spectrometry. Quantum mechanical investigations density functional theory calculations and the Monte Carlo simulation on corrosion behavior of QN1 and QN2 compounds were also conducted, and satisfying correlation was noticed between the results of corrosion measurement methods and quantum mechanical evaluations. © 2020, King Fahd University of Petroleum & Minerals.

키워드