Tuning corrosion inhibition of mild steel via positional bromine substitution in antipyrine-derived amides: mechanistic insights from electrochemical and DFT investigations
5 affiliations
- 1Materials Laboratory, Department of Chemistry, Mirpur University of Science and Technology (MUST) Mirpur-10250 AJK Pakistan
- 2GSK, Carbon Neutral Laboratories for Sustainable Chemistry, University of Nottingham Jubilee Campus, 6 Triumph Rd, Lenton Nottingham NG7 2GT UK
- 3Department of Chemistry and Biochemistry, Miami University 651 E. High Street Oxford Ohio 45056 USA
- 4Department of Chemical Engineering, Faculty of Engineering, Islamic University of Madinah 42351 Madinah Saudi Arabia
- 5Department of Physics, Engineering Physics and Astronomy, Queen's University Kingston Ontario K7L-3N6 Canada
Abstract
Corrosion of mild steel in acidic environments is a major industrial challenge, especially during pickling and descaling, requiring efficient organic corrosion inhibitors with enhanced adsorption and stability. In this study, three novel brominated amide derivatives of 4-aminoantipyrine (M1–M3) were synthesized to investigate the influence of bromine substitution position and effect of steric hindrance caused by alkyl group on corrosion inhibition efficiency. The synthesized compounds were characterized using Fourier Transform Infrared (FT-IR) spectroscopy, Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy, Carbon-13 Nuclear Magnetic Resonance (13C NMR) spectroscopy, Correlation Spectroscopy (COSY), Heteronuclear Single Quantum Coherence spectroscopy (HSQC), and High-Resolution Mass Spectrometry (HRMS) techniques. Corrosion inhibition potentials were determined via weight loss and electrochemical methods. Surface morphology was analyzed using scanning electron microscopy (SEM), while Density Functional Theory (DFT) measurements were employed to determine electronic properties and adsorption behavior. The inhibitors shows concentration dependent protection, with M1 showing the highest inhibition efficiency, reaching 95.91 ± 0.6% from polarization measurements and 95.75 ± 0.6% from EIS measurements at 0.5 mM, respectively. EIS measurements showed a progressive increase in polarization resistance and decrease in double-layer capacitance with increasing inhibitor concentration, indicating enhanced interfacial surface coverage. Potentiodynamic polarization results identified M1–M3 as mixed-type inhibitors, affecting both anodic and cathodic corrosion reactions. Thermodynamic analysis of M1 revealed the ΔEa of 36.86 ± 0.9 to 28.28 ± 0.7 kJ mol−1, ΔH of 34.22 ± 0.6 to 25.64 ± 0.4 kJ mol−1, ΔS of −181.42 ± 2.1 to −214.51 ± 3.2 J mol−1 K−1 and ΔG of −15.56 ± 0.28 to −12.41 ± 0.19 kJ mol−1 on increasing the concentration (0.2–1.0 mM) at 303–333 K, indicating spontaneous adsorption with predominantly physical adsorption. The SEM analysis confirmed a smoother surface of mild steel in presence of inhibitors, while DFT calculations provided molecular level insight into their electronic characteristics and probable interaction sites. Results demonstrate that bromine substitution and molecular structure significantly influence inhibition efficiency. The combined experimental, thermodynamic, and theoretical findings confirm that the bromine substituted inhibitors act as efficient mixed type inhibitors through spontaneous adsorption and stable film formation, making them promising for industrial applications.
Related
- Radical Anion of Oxalate Esters: Electrochemical and EPR Investigations
- A green and sustainable incorporation of bi- and ter-thiophenes into 1,4-dihydropyridines: synthetic, mechanistic and photophysical investigations
- Ethylene-bridged Periodic Mesoporous Organosilica Nanoparticles: controlling architecture through mechanistic investigations
- Cation substitution and oxygen vacancies engineering in ZnNi0.1Co1.9O4 spinel oxide for sensitive electrochemical detection of lead(ii) ions in environmental water and soil samples
- Selectivity in Homolytic Substitution at a Tertiary Phosphine Center: Mechanistic Insights into Dealkanation Reaction.
BibTeX
@article{afaq2026tuning,
title = {{Tuning corrosion inhibition of mild steel via positional bromine substitution in antipyrine-derived amides: mechanistic insights from electrochemical and DFT investigations}},
author = {Adil Afaq and Muhammad Aamir and Shahid Aziz and Simon Woodward and Zaroon Sajid and Muhammad Haroon and Md. Akhtaruzzaman and Jean-Michel Nunzi},
journal = {RSC advances},
year = {2026},
month = oct,
doi = {10.1039/d6ra06574k},
url = {https://europepmc.org/article/PMC/PMC13656029},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - Tuning corrosion inhibition of mild steel via positional bromine substitution in antipyrine-derived amides: mechanistic insights from electrochemical and DFT investigations
AU - Adil Afaq
AU - Muhammad Aamir
AU - Shahid Aziz
AU - Simon Woodward
AU - Zaroon Sajid
AU - Muhammad Haroon
AU - Md. Akhtaruzzaman
AU - Jean-Michel Nunzi
PY - 2026
DA - 2026/10/12
JO - RSC advances
DO - 10.1039/d6ra06574k
UR - https://europepmc.org/article/PMC/PMC13656029
AB - Corrosion of mild steel in acidic environments is a major industrial challenge, especially during pickling and descaling, requiring efficient organic corrosion inhibitors with enhanced adsorption and stability. In this study, three novel brominated amide derivatives of 4-aminoantipyrine (M1–M3) were synthesized to investigate the influence of bromine substitution position and effect of steric hindrance caused by alkyl group on corrosion inhibition efficiency. The synthesized compounds were characterized using Fourier Transform Infrared (FT-IR) spectroscopy, Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy, Carbon-13 Nuclear Magnetic Resonance (13C NMR) spectroscopy, Correlation Spectroscopy (COSY), Heteronuclear Single Quantum Coherence spectroscopy (HSQC), and High-Resolution Mass Spectrometry (HRMS) techniques. Corrosion inhibition potentials were determined via weight loss and electrochemical methods. Surface morphology was analyzed using scanning electron microscopy (SEM), while Density Functional Theory (DFT) measurements were employed to determine electronic properties and adsorption behavior. The inhibitors shows concentration dependent protection, with M1 showing the highest inhibition efficiency, reaching 95.91 ± 0.6% from polarization measurements and 95.75 ± 0.6% from EIS measurements at 0.5 mM, respectively. EIS measurements showed a progressive increase in polarization resistance and decrease in double-layer capacitance with increasing inhibitor concentration, indicating enhanced interfacial surface coverage. Potentiodynamic polarization results identified M1–M3 as mixed-type inhibitors, affecting both anodic and cathodic corrosion reactions. Thermodynamic analysis of M1 revealed the ΔEa of 36.86 ± 0.9 to 28.28 ± 0.7 kJ mol−1, ΔH of 34.22 ± 0.6 to 25.64 ± 0.4 kJ mol−1, ΔS of −181.42 ± 2.1 to −214.51 ± 3.2 J mol−1 K−1 and ΔG of −15.56 ± 0.28 to −12.41 ± 0.19 kJ mol−1 on increasing the concentration (0.2–1.0 mM) at 303–333 K, indicating spontaneous adsorption with predominantly physical adsorption. The SEM analysis confirmed a smoother surface of mild steel in presence of inhibitors, while DFT calculations provided molecular level insight into their electronic characteristics and probable interaction sites. Results demonstrate that bromine substitution and molecular structure significantly influence inhibition efficiency. The combined experimental, thermodynamic, and theoretical findings confirm that the bromine substituted inhibitors act as efficient mixed type inhibitors through spontaneous adsorption and stable film formation, making them promising for industrial applications.
SN - 2046-2069
ER -