Advanced corrosion protection for mild steel in acidic environments: The power of 3-imino-3H-benzo[f]chromene-2-carboxamide

• H.H. Al-Doori¹, M.A.I. Al-Hamid², A.F. Mahmood³, A.A.H. Kadhum⁴ and A.A. Alamiery⁵

¹ Al-Karkh University of Science, Baghdad P.O. Box: 10001, Baghdad, Iraq
² Energy and Renewable Energies Technology Center, University of Technology, Baghdad P.O. Box: 10001, Baghdad, Iraq
³ Oil and Gas Engineering Department, University of Technology, Baghdad P.O. Box: 10001, Baghdad, Iraq
⁴ Al-Ameed University College, P.O. Box: 56001, Karbala, Iraq
⁵ Al-Ayen Scientific Research Center, Al-Ayen Iraqi University, AUIQ, An Nasiriyah, P.O. Box: 64004, Thi Qar, Iraq

Abstract: This research investigates the efficacy of 3-imino-3H-benzo[f]chromene-2-carboxamide (IB[f]CC) as a corrosion inhibitor for mild steel in hydrochloric acid. Through a combination of weight loss measurements and density functional theory (DFT) calculations, the results reveal an impressive inhibition efficiency of 91.6% at 303 K after five hours of immersion. Corrosion rates lower notably with growing immersion times (1, 5, 10, 24, and 48 hours), with inhibition efficiency stabilizing beyond 10 hours. Additionally, a moderate upward thrust in efficiency is found as the temperature increases from 303 to 333 K. Adsorption of the inhibitor on the steel surface follows the Langmuir isotherm, suggesting a blended mode of physical and chemical adsorption. DFT calculations suggest sturdy interactions between the inhibitor’s useful functional groups – lactone, benzene rings, amino, carbonyl, and imino – with iron atoms, resulting in a stable protecting layer. The findings highlight IB[f]CC as a promising candidate for reinforcing the corrosion resistance of mild steel in acid-resistant materials used in industrial applications.

Keywords: corrosion, density functional theory, Langmuir, immersion time, mass loss

Int. J. Corros. Scale Inhib., 2025, 14, no. 1, 397-419
doi: 10.17675/2305-6894-2025-14-1-24

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