Chalcone oxime derivatives as new inhibitors corrosion of carbon steel in 1 M HCl solution

Experimental and theoretical approach for a better understanding of the mechanisms of adsorption and inhibition of corrosion for carbon steel by thiazolidine derivatives in 1 M HCl medium

Many sectors have employed various strategies to prolong the life of steel because of its strength and high manufacturing and installation costs. The use of organic inhibitors has been widespread in recent years. The purpose of this investigation is to evaluate the activity of recently synthesized derivatives, namely (Z)-5-benzylidenethiazolidine-2,4-dione (FT-2a), (Z)-5-(2,4-dichlorobenzylidene)thiazolidine-2,4-dione (FT-2c), and (Z)-3-allyl-5-(2,4-dichlorobenzylidene)thiazolidine-2,4-dione (FT-3c), in inhibiting corrosion through electrochemical assays on carbon steel (CS) in 1 M HCl at 303 K. The chosen products (FT-2a, FT-2c, and FT-3c) were selected as corrosion inhibitors due to their eco-friendly composition and biodegradability, aligning with the increasing demand for sustainable products. The findings revealed that the inhibitory activities of FT-2a, FT-2c, and FT-3c improved with increasing concentration, reaching maximum values of 94.10%, 95.30%, and 96.50% for FT-2a, FT-2c, and FT-3c, respectively. In contrast, the corrosion mitigation effectiveness decreased by around 22.69% (for FT-2a), 18.87% (for FT-2c), and 17.81% (for FT-3c) with the rise in temperature from 303 to 333 K. An overview of potentiodynamic polarization (PDP) plots revealed that the three products function as mixed-type inhibitors and adsorb according to the Langmuir isotherm in the corrosive 1 M HCl solution. Surface analysis [scanning electron microscopy (SEM-EDX), contact angle (CA), and X-ray diffraction (XRD)] of the CS specimens demonstrated that the chosen inhibitors were absorbed and formed protective layers that mitigated the impact of corrosion. Strong interactions between FT-2a, FT-2c, and FT-3c molecules and Fe ions at particular atomic sites were identified by analysis of UV-visible spectra. Using techniques such as Fukui functions, molecular dynamics simulations (MDS), and DFT calculations, the impact of the molecular structure of FT-2a, FT-2c, and FT-3c on their capacity to suppress corrosion was investigated. In addition, the protonation of thiazolidine derivatives in acidic media was studied. The results of these various methods were very coherent.

Gemini cationic surfactant of 1, 3-bis (dodecyl dimethyl ammonium chloride) propane as a novel excellent inhibitor for the corrosion of cold rolled steel in HCl solution

Gemini surfactants have become the research focus of novel excellent inhibitors because of their special structure (two amphiphilic moieties covalently connected at head group by a spacer) and excellent surface properties. It is proved by theoretical calculations that 1, 3-bis (dodecyl dimethyl ammonium chloride) propane (BDDACP) molecules can perform electron transfer with Fe (110). And it has a small fraction free volume, thus greatly reducing the diffusion and migration degree of corrosive particles. The potentiodynamic polarization curve showed that coefficients of cathodic and anodic reaction less than 1 and polarization resistance increased to 1602.9 Ω cm-2 after added BDDACP, confirming that BDDACP significantly inhibited the corrosion reaction by occupying the active site. The electrochemical impedance spectrum of imperfect semi-circle shows that the system resistance increases and double layer capacitance after added BDDACP. Weight loss tests also confirmed that BDDACP forms protective film by occupying the active sites on steel surface, and the maximum inhibition efficiency is 92 %. Comparison of the microscopic morphology showed that steel surface roughness was significantly reduced after added BDDACP. The results of time-of-flight secondary ion mass spectrometry show that steel surface contains some elements from BDDACP, which confirms the adsorption of BDDACP on steel surface.

Adsorption and Inhibition Mechanisms of New Pyrazole Derivatives for Carbon Steel Corrosion in Hydrochloric Acid Solutions Based on Experimental, Computational, and Theoretical Calculations

The study aims to synthesize two green pyrazole compounds, N-((1H-pyrazol-1-yl)methyl)-4-nitroaniline (L4) and ethyl 5-methyl-1-(((4-nitrophenyl)amino)methyl)-1H-pyrazole-3-carboxylate (L6), and test their action as corrosion inhibitors for carbon steel (CS) in a 1 M HCl solution. Both chemical and electrochemical methods, namely, gravimetric measurements (WL), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS), were used to assess the efficiency of the investigated molecules. DFT calculations at B3LYP/6-31++G (d, p) and molecular dynamics simulation were used to carry out quantum chemical calculations in order to link their electronic characteristics with the findings of experiments. The organic products exhibited good anticorrosion ability, with maximum inhibition efficiencies (IE %) of 91.8 and 90.8% for 10-3 M L6 and L4, respectively. In accordance with PDP outcomes, L6 and L4 inhibitors act as mixed-type inhibitors. Assessment of the temperature influence evinces that both L4 and L6 are chemisorbed on CS. The adsorption of L4 and L6 on CS appears to follow the Langmuir isotherm. Scanning electron microscopy and UV-visible disclose the constitution of a barrier layer, limiting the accessibility of corrosive species to the CS surface. Theoretical studies were performed to support the results derived from experimental techniques (WL, PDP, and EIS).

Insight into the corrosion inhibition of Biebersteinia multifida root extract for carbon steel in acidic medium

In this project, the protective effect of Biebersteinia multifida root extract (BMRE) against corrosion of 1018 low carbon steel (1018LCS) in HCl solutions was appraised by assessing weight loss, electrochemical impedance spectroscopy (EIS), and polarization at 25 °C. The maximum inhibitory efficacy for the concentration of 1 g/l of the BMRE was 92.8% at 25 °C after 2 h and increased to 95.3% after 24 h of immersion. Polarization experiments have shown that the extract in acidic solutions can act as a mixed corrosion inhibitor. The corrosion inhibitory efficacy of BMRE decreased with increasing temperature, and at all temperature settings studied, the adsorption of BMRE molecules on 1018 LCS was consistent with the Langmuir adsorption isotherm. The Scanning Electron Microscopy (SEM) analysis confirmed the protection of 1018 LCS in the acidic solution containing BMRE extract. Quantum chemistry studies of four main constituents of the extract called vasicinone, umbelliferon, scopoletin, and ferulic acid were performed by density functional theory, DFT, in neutral and protonated states. Calculated quantum parameters were used to investigate the active sites and donor-receptor interactions of molecules.

Efficient Synthesis of 6,7-Dihydro-5H-cyclopenta[b]pyridine-3-carbonitrile Compounds and Their Applicability As Inhibitor Films for Steel Alloy Corrosion: Collective Computational and Practical Approaches

An effective method for designing new heterocyclic compounds of 6,7-dihydro-5H-cyclopenta[b]pyridine-3-carbonitrile derivatives (CAPDs) was presented through cyclocondensation reaction between 2,5-diarylidenecyclopentanone derivatives and propanedinitrile, and the cyclocondensation reaction succeeded using a sodium alkoxide solution (sodium ethoxide or sodium methoxide) as the reagent and the catalyst. The synthesized CAPD derivatives were employed as novel inhibitors for carbon steel (CS) corrosion in a molar H2SO4 medium. The corrosion protection proficiency was investigated by electrochemical measurements (open circuit potential vs time (E OCP vs t), potentiodynamic polarization plots (PDP), and electrochemical impedance spectroscopy (EIS)) and surface morphology (scanning electron microscopy (SEM)) examinations. The results show that the CAPD derivatives exhibit mixed type inhibitors and a superior inhibition efficiency of 97.7% in the presence of 1.0 mM CAPD-1. The adsorption of CAPD derivatives on the CS interface follows the Langmuir isotherm model, including physisorption and chemisorption. Scanning electron microscopy (SEM) exploration confirmed the adsorption of the CAPD derivatives on the CS substrate. Monte Carlo (MC) simulations and DFT calculations revealed that the efficacy of the CAPD molecules correlates well with their structures, and this protection was attributed to their adsorption on the CS surface.

Performance Evaluation of New Chalcone Oxime Functionalized Graphene Oxide as a Corrosion Inhibitor for Carbon Steel in a Hydrochloric Acid Solution

This study aims to synthesize new chalcone oxime functionalized graphene oxide (CO-GO) and investigate the enhancement in corrosion protection. The morphology and structure of the synthesized CO-GO have been characterized by elemental analysis: Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). Moreover, the effectiveness of corrosion inhibition was investigated by utilizing electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP). The results of the above analyses demonstrate that CO-GO has an outstanding corrosion inhibitor performance of up to 94% and acts as a mixed-type inhibitor with a primarily anodic action. The effect of temperature on a carbon steel surface indicates that the tested composites are chemisorbed. A few techniques were able to provide surface characterization such as scanning electron microscopy and ultraviolet (UV)-visible spectroscopy to confirm inhibitor adsorption on the carbon steel surface.