Exploring chromone derivatives as environmentally friendly corrosion inhibitors for mild steel in acidic environments: A comprehensive experimental and DFT study

• Y.K. Al-Majedy¹, H.H. Ibraheem¹, A.A. Issa¹ and A. Alamiery²

¹ Applied Science Department, University of Technology, Baghdad, 10001 Iraq
² Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, University Kebangsaan Malaysia (UKM), Bangi P.O. Box 43000, Selangor, Malaysia

Abstract: The chemical structure of a novel coumarin derivative, 1,4-phenylene-bis(methan-1-yl-1-ylidene)bis(azan-1-yl-1-ylidene)bis(7-hydroxy-4-methylquinolin-2(1H)-one) (PMAQ), was elucidated using Fourier Transform Infrared Spectroscopy (FT-IR) and Nuclear Magnetic Resonance (NMR). The corrosion inhibition potential of PMAQ was investigated on mild steel in 1 M hydrochloric acid at temperatures ranging from 303 K to 333 K, using gravimetric analysis and scanning electron microscopy (SEM) for surface examination. PMAQ exhibited notable effectiveness as a corrosion inhibitor, with concentrations ranging from 0.1 mM to 0.5 mM. The gravimetric analysis revealed that PMAQ effectively inhibited mild steel corrosion in highly acidic solutions. The inhibitory efficiency was found to be dependent on both the inhibitor concentration and the solution temperature. Increasing the inhibitor concentration resulted in enhanced inhibition, reaching a maximum efficiency of 85.5% at a concentration of 0.5 mM and 303 K. The experimental results aligned well with the adsorption studies. Furthermore, the impact of different substituents (nitro, hydroxyl, methoxy, and amino groups) on the corrosion inhibitor PMAQ was investigated. Density Functional Theory (DFT) calculations were performed using the [B3LYP/6-311G(d,p)] level of theory. Our findings revealed that the introduction of nitro groups enhanced the inhibitory efficiency. This study significantly improved the understanding of the inhibitory efficiency of corrosion inhibitor molecules through the comparison with other corrosion inhibitor compounds.

Keywords: chromone derivatives, corrosion inhibitors, mild steel, acidic environments, environmentally friendly, DFT study

Int. J. Corros. Scale Inhib., 2023, 12, no. 3, 1028-1051
doi: 10.17675/2305-6894-2023-12-3-14

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