Synthesis, physicochemical properties, theoretical and electrochemical studies of tetraglycidyl methylenedianiline

Chemical, electrochemical, and quantum investigation into the use of an organophosphorus derivative to inhibit copper corrosion in acidic environments

In order to protect the copper against corrosion, a novel corrosion inhibitor known as diphenyl ((2-aminoethyl) amino) (4-methoxyphenyl) methyl) phosphonate (DAMP) was developed. Acid solutions of HCl and H2SO4 were the aggressive solutions employed in this study. Analysis using the FT-IR, 1H-NMR, 31P-NMR, 13C-NMR and BET confirmed that the DAMP was successfully synthesized. The anti-corrosion capabilities of DAMP are evaluated using a combination of chemical, electrochemical and quantum studies. The DAMP has been found to be crucial in preventing the corrosion of copper in both HCl and H2SO4 acid. This was obviously implied by the observation that the corrosion rate of copper in acid solutions decreased when DAMP was added. It is significant to note that 180 ppm produced the highest levels of inhibiting efficiency (96.6% for HCl and 95.2% for H2SO4). The tendency of DAMP to adsorb on the surface of copper through its hetero-atoms (O, N, and P) is the main factor for the anti-corrosion capabilities of DAMP. Results from SEM/EDX tests supported this. The actual adsorption takes place via various active centers, physical and chemical mechanisms that are coordinated with the estimated quantum parameters. Additionally, the adsorption of DAMP adheres to the Langmuir isotherm.

Surface adsorption and corrosion resistance performance of modified chitosan: Gravimetric, electrochemical, and computational studies

Two novel chitosan derivatives (water soluble and acid soluble) modified with thiocarbohydrazide were produced by a quick and easy technique using formaldehyde as links. The novel compounds were synthesized and then characterized by thermogravimetric analysis, elemental analysis, nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and differential scanning calorimetry. Their surface morphologies were examined using scanning electron microscopy. These chitosan derivatives could produce pH-dependent gels. The behavior of mild steel in 5 % acetic acid, including both inhibitors at various concentrations, was investigated using gravimetric and electrochemical experiments. According to the early findings, both compounds (TCFACN and TCFWCN) functioned as mixed-type metal corrosion inhibitors. Both inhibitors showed their best corrosion inhibition efficiency at 80 mg L-1. TCFACN and TCFWCN, showed approximately 92 % and 94 % corrosion inhibition, respectively, at an optimal concentration of 80 mg L-1, according to electrochemical analysis. In the corrosion test, the water contact angle of the polished MS sample at 87.90 °C was reduced to 51 °C. The water contact angles for MS inhibited by TCFACN and TCFWCN in the same electrolyte were greater, measuring 78.10 °C and 93.10 °C, respectively. The theoretical results also support the experimental findings.

Hybrid epoxy/Br inhibitor in corrosion protection of steel: experimental and theoretical investigations

The corrosion of carbon steel infrastructure in acidic environments poses significant economic and safety challenges. Traditional inhibitors such as chromates are being phased out due to toxicity concerns. Thus, there is a need to develop effective and sustainable green alternatives. In this work, we evaluated an epoxy-based inhibitor, bisphenol A tetrabromo dipropoxy dianiline tetraglycidyl ether (TGEDADPTBBA), for protecting carbon steel against corrosion in 1 M hydrochloric acid. An integrated experiment-computation approach was employed. Polarization curves and electrochemical impedance spectroscopy were used to assess the inhibition efficiency and mechanism of TGEDADPTBBA. Quantum chemical calculations and molecular dynamics simulations provided atomic-level insights into adsorption behavior. Scanning electron microscopy with energy-dispersive X-ray spectroscopy characterized the surface morphology. The results showed that TGEDADPTBBA acted as a highly effective mixed-type inhibitor, achieving over 95% inhibition efficiency at a 10-3 M concentration. It suppressed corrosion currents while increasing the charge transfer resistance. Theoretical studies revealed that TGEDADPTBBA adsorbed onto steel surfaces via both electrostatic and van der Waals interactions. This stable adsorption facilitated the formation of a protective barrier layer, as observed experimentally. Notably, our work demonstrated the synergistic potential of combining experimental corrosion testing with computational modeling to develop structure-property relationships for innovative inhibitor design. This integrated approach offers insight into inhibition mechanisms and presents TGEDADPTBBA as an attractive green corrosion inhibitor alternative for industrial applications.

Electrochemical, surface morphological and computational evaluation on carbohydrazide Schiff bases as corrosion inhibitor for mild steel in acidic medium

Anticorrosion and adsorption behaviour of synthesized carbohydrazide Schiff bases, namely (Z)-N'-(4-hydroxy-3-methoxybenzylidene)-6-methyl-2-oxo-4-phenyl-1,2,3,4-tetrahydropyrimidine-5-carbohydrazide(MBTC) and (Z)-N'-(3,4-dichlorobenzylidene)-6-methyl-2-oxo-4-phenyl-1,2,3,4-tetrahydropyrimidine-5-carbohydrazide (CBTC) was examined for mild steel (MS) in 15% HCl medium. The corrosion inhibition study was performed by using gravimetric, thermodynamic, electrochemical and theoretical studies including density functional theory (DFT), molecular dynamic simulation (MDS) and Monte Carlo simulations (MCS). The outcomes in terms of corrosion inhibition efficiency using electrochemical impedance spectroscopy (EIS) method at 303 K and 150 ppm concentration were 96.75% for MBTC and 95.14% for CBTC. Both inhibitors adsorbed on the MS surface through physical as well as chemical adsorption and followed the Langmuir isotherm. The mixed-type nature of both inhibitors was identified by polarization results. Surface analysis was done using FESEM, EDX, AFM and XPS studies and results showed that a protective layer of inhibitor molecules was developed over the surface of MS. The results of DFT, MCS and MDS are in accordance with experimental results obtained by weight loss and electrochemical methods.