Hydrazone-based green corrosion inhibitors for API grade carbon steel in HCl: Insights from electrochemical, XPS, and computational studies

Development of pH-sensitive chitosan/plant extract microcapsules: Enhanced corrosion protection for carbon steel in HCl solution

In recent years, controlled-release green corrosion inhibitors have become a research hotspot in the field of corrosion. In this study, chitosan/plant extract microcapsules (GCI@CS) loaded with Ambrosia artemisiifolia extract (green corrosion inhibitor, GCI) were prepared by emulsification cross-linking. Both the functional groups and micromorphology of GCI@CS were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and optical microscopy (OM). The loading capacity and encapsulation efficiency of GCI@CS were analyzed using UV-Vis spectroscopy. The corrosion inhibition performance of GCI@CS on carbon steel (C-steel) in 1.0 mol/L HCl was investigated using electrochemical impedance spectroscopy (EIS). The results indicated that GCI@CS, as a pH-sensitive microcapsule, can provide effective corrosion protection for C-steel in HCl solution. Notably, the corrosion resistance of GCI@CS improved with increasing concentration and time. The corrosion inhibition efficiency (ηEIS) of C-steel immersed in 1.0 mol/L HCl (with 500 mg/L GCI@CS) for 24 h reached 93.48 %. This study provides important insights for the industrial deployment of green corrosion inhibitors with controlled release properties.

Synthesis of new binary trimethoxyphenylfuran pyrimidinones as proficient and sustainable corrosion inhibitors for carbon steel in acidic medium: experimental, surface morphology analysis, and theoretical studies

In this study, synthesis and assessment of the corrosion inhibition of four new binary heterocyclic pyrimidinones on CS in 1.0 M hydrochloric acid solutions at various temperatures (30-50 °C) were investigated. The synthesized molecules were designed and synthesized through Suzuki coupling reaction, the products were identified as 5-((5-(3,4,5-trimethoxyphenyl)furan-2-yl)methylene)pyrimidine-2,4,6(1H,3H,5H)-trione (HM-1221), 2-thioxo-5-((5-(3,4,5-trimethoxyphenyl)furan-2-yl)methylene)dihydropyrimidine-4,6(1H,5H)-dione (HM-1222), 1,3-diethyl-2-thioxo-5-((5-(3,4,5-trimethoxyphenyl)furan-2-yl)methylene)dihydropyrimidine-4,6(1H,5H)-dione (HM-1223) and 1,3-dimethyl-5-((5-(3,4,5-trimethoxyphenyl)furan-2-yl)methylene)pyrimidine-2,4,6(1H,3H,5H)-trione (HM-1224). The experiments include weight loss measurements (WL), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP). From the measurements, it can be shown that the inhibition efficiency (η) of these organic derivatives increases with increasing the doses of inhibitors. The highest η recorded from EIS technique were 89.3%, 90.0%, 92.9% and 89.7% at a concentration of 11 × 10-6 M and 298 K for HM-1221, HM-1222, HM-1223, and HM-1224, respectively. The adsorption of the considered derivatives fit to the Langmuir adsorption isotherm. Since the ΔGoads values were found to be between - 20.1 and - 26.1 kJ mol-1, the analyzed isotherm plots demonstrated that the adsorption process for these derivatives on CS surface is a mixed-type inhibitors. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), atomic force microscope (AFM) and Fourier- transform infrared spectroscopy (FTIR) were utilized to study the surface morphology, whereby, quantum chemical analysis can support the mechanism of inhibition. DFT data and experimental findings were found in consistent agreement.

Helmet-Roled Molecules Carrying Double Metronidazole Frameworks and Phenyl Ring for Strengthening Adsorption and Anticorrosion on Mild Steel

This study prepared new helmet-roled molecules (HMs) carrying metronidazole frameworks and a phenyl ring for strengthening adsorption and anticorrosion on mild steel. The adsorption of the HMs on the copper surface was understood by material simulation computation. Furthermore, the surface analysis experiments suggest that the studied molecules could be adsorbed to a mild steel surface through the chemical coordination bonding. The remarkable corrosion resistance of the HMs for mild steel in HCl was surveyed by potentiodynamic polarization and electrochemical impedance spectroscopy at 298 K. The HMs including two metronidazole skeletons displayed the stronger corrosion inhibition effect on mild steel than the HM1 bearing one single metronidazole part (the corrosion inhibition efficiency, HM3, 98.03%, HM2, 95.14%, HM1, 88.72%). The results presented in this study provided an efficient strategy to develop new clinical medicine-based corrosion inhibitors for metal in acid medium through molecular preconstruction.

Current Overview of Corrosion Inhibition of API Steel in Different Environments

API (American Petroleum Institute) steels are the most employed metal alloys in the oil industry due to their outstanding mechanical properties; however, their protection is considered as an imperative matter because of their corrosion damage vulnerability when exposed to different surroundings that provoke a rate increase in the concomitant redox reactions. This problematic situation becomes more relevant when the generation and/or use of one or various aqueous corrosive environments occur, in addition to process conditions, the result of which is extremely difficult to be controlled. For these reasons, the internal and external protection of exposed metallic systems are considered as a fundamental concern, where internal corrosion is often controlled through the addition of corrosion inhibitors (CIs). The present review analyzes researchers' contributions in the last years to the study and evaluation of CIs for API steel in different corrosive media featuring HCl, H2SO4, H3NSO3H, CO2, H2S, NaCl, and production water under different temperature and flow conditions. Different CIs derived from plant extracts, drugs, nanoparticles, or ionic liquids, mainly destined for acid media, were found. Throughout the review, an exhaustive analysis of inhibition process results is carried out based on gravimetric and/or electrochemical techniques that consider the weight loss of the metallic material and electrical behavior (current density, resistance, capacitance, frequency, impedance, etc.). Likewise, the results of computational analyses and those of surface analysis techniques were taken into account to reinforce the study of CIs.

Corrosion Prevention of Copper in 2.0 M Sulfamic Acid Using Novel Plant Extract: Chemical, Electrochemical, and Theoretical Studies

Copper corrosion was suppressed when a lupine extract was immersed in a 2 M sulfamic acid (H2NSO3H) solution. Numerous methods, including mass loss (ML), dynamic potential polarization (PL), and electrochemical impedance (EIS), were employed in these experiments, in addition to theoretical computations such as density functional theory (DFT), Fukui function, and Monte Carlo simulations. Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) were used to analyze the Cu surface's composition and determine its form. Mass loss (ML) was used to examine the inhibition rate of copper corrosion in sulfamic acid at 25 °C in the presence of lupine extract. After examining how it behaved throughout the adsorption process on copper, it was discovered that it follows the Langmuir isotherm and chemical adsorption. An analysis of the PL curves indicates that the lupine extract is a mixed-type inhibitor. It was shown that the inhibitory efficiency increased to 84.2% with increasing lupine concentration. Additionally, as the data show, the efficiency of inhibitors is diminished by increasing temperatures. Theoretical calculations and experimental data were compared using Monte Carlo simulation (MC) and density functional theory (DFT).

Novel biphenylidene-thiopyrimidine derivatives as corrosion inhibitors for carbon-steel in oilfield produced water

The inhibiting efficiency of three newly synthesized organic compounds:5-((4'-(dimethylamino)-[1,1'-biphenyl]-4-yl)methylene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione (HM-1228), 5-((4'-(dimethylamino)-[1,1'-biphenyl]-4-yl)methylene)-2-thioxodihydropyrimidine-4,6(1H,5H)-dione (HM-1227) and 5-((4'-(dimethylamino)-[1,1'-biphenyl]-4-yl)methylene)pyrimidine-2,4,6(1H,3H,5H)-trione (HM-1226) in oilfield produced water on the corrosion of carbon steel has been examined via electrochemical measurements; potentiodynamic polarization (PDP) and electrochemical impedance (EIS) techniques. The adsorption of these compounds on the surface of carbon steel followed Langmuir isotherm. In addition, the surface morphology of uninhibited and inhibited carbon steel was examined by Atomic Force Microscopy (AFM), observing surface improvement when carbon steel samples exposed to the inhibited corrosive solutions. The average surface roughness (Ra) in oilfield produced water solution in the presence of 0.5 mM of HM-1228 inhibitor was 138.28 nm compared to the uninhibited surface 571.62 nm. To explore the corrosion inhibition mechanism, quantum chemical calculations and Monte Carlo simulations were utilized. The HM-1228 inhibitor demonstrated the highest corrosion inhibition efficiency at 94.8% by PDP measurements. The higher corrosion inhibition of compound HM-1228 can be attributed to the presence of di-N-ethyl groups that enhance both electron donating ability and lipophilic properties.

Synthesis of Ammonium-Based ILs with Different Lengths of Aliphatic Chains and Organic Halogen-Free Anions as Corrosion Inhibitors of API X52 Steel

In the present work, synthesis and characterization of 15 ionic liquids (ILs) derived from quaternary ammonium and carboxylates were carried out in order to proceed to their evaluation as corrosion inhibitors (CIs) of API X52 steel in 0.5 M HCl. Potentiodynamic tests confirmed the inhibition efficiency (IE) as a function of the chemical configuration of the anion and cation. It was observed that the presence of two carboxylic groups in long linear aliphatic chains reduced the IE, whereas in shorter chains it was increased. Tafel-polarization results revealed the ILs as mixed-type CIs and that the IE was directly proportional to the CI concentration. The compounds with the best IE were 2-amine-benzoate of N,N,N-trimethyl-hexadecan-1-ammonium ([THDA+][-AA]), 3-carboxybut-3-enoate of N,N,N-trimethyl-hexadecan-1-ammonium ([THDA+][-AI]), and dodecanoate of N,N,N-trimethyl-hexadecan-1-ammonium ([THDA+][-AD]) within the 56-84% interval. Furthermore, it was found that the ILs obeyed the Langmuir adsorption isotherm model and inhibited the corrosion of steel through a physicochemical process. Finally, the surface analysis by scanning electron microscopy (SEM) confirmed less steel damage in the presence of CI due to the inhibitor-metal interaction.

Superior Long-Term Corrosion Inhibition of N80 Steel by New Eco-friendly Hydrazone-Based Compounds in a Simulated Oil Well Acidizing Environment: Establishing the Mechanism at the Molecular Level

The acid treatment process of production wells is one of the most acid-induced corrosive processes. Corrosion inhibitors are an effective tool to inhibit the acids employed in acidizing treatments. Herein, new eco-friendly hydrazone-based compounds, namely, 2-(4-isobutylphenyl)-N-((1E,2E)-3-phenylallylidene) propanehydrazide (IPP) and N'-cyclohexylidene-2-[4-(2-methylpropyl)phenyl] propanehydrazide (CIP), were prepared through the functionalization of ibuprofen (IBF) and applied for corrosion mitigation of N80 steel in 15 wt % HCl (referred to hereafter as blank). The anticorrosion performance of selected compounds was investigated by employing weight loss (WL), potentiodynamic polarization curves (PPCs), and electrochemical impedance spectroscopy (EIS), complemented by scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses. In addition, density functional theory-based tight-binding (DFTB) modeling was conducted to get molecular-level insights into inhibitor-metal bonding. Experimental results revealed excellent long-term corrosion inhibition efficiency at very low concentrations of inhibitors and a mixed-type inhibition process. Numerically, N80 steel polarization resistance increased from 5.51 Ω cm² in blank to 608.4 and 396 Ω cm² in blank inhibited with 5 × 10^-3 mol/L of IPP and CIP, respectively, equivalent to 99% and 98% inhibition efficiency based on EIS experiments. Besides, SEM and AFM images showed that, after addition to 15 wt % HCl, inhibitors could effectively prevent the acid attack on the N80 steel surface. The fitting of experimental data to adsorption isotherms indicated that inhibitors' adsorption followed the Langmuir isotherm model and mixed physicochemical adsorption on the metal surface. The DFTB simulation revealed that inhibitor molecules can create covalent and physical interactions with iron atoms, which is further confirmed by partial density of states (PDOSs) analysis.

Inhibition Mechanism of Some Vinylalkylimidazolium-Based Polymeric Ionic Liquids against Acid Corrosion of API 5L X60 Steel: Electrochemical and Surface Studies

A corrosion inhibition mechanism of API 5L X60 steel exposed to 1.0 M H₂SO₄ was proposed from the evaluation of three vinylalkylimidazolium poly(ionic liquids) (PILs), employing electrochemical and surface analysis techniques. The synthesized PILs were classified as mixed-type inhibitors whose surface adsorption was promoted mainly by bromide and imidazolate ions, which along with vinylimidazolium cations exerted a resistive effect driven by a charge transfer process by means of a protective PIL film with maximal efficiency of 85% at 175 ppm; the steel surface displayed less surface damage due to the formation of metal-PIL complex compounds.

Corrosion inhibition of a novel antihistamine-based compound for mild steel in hydrochloric acid solution: experimental and computational studies

Focused on the assessment of the diphenhydramine hydrochloride (DPH) capabilities as an alternative to conventional and harmful industrial corrosion inhibitors, electrochemical techniques were employed. The optimum concentration of 1000 ppm was determined by molecular simulation and validated through electrochemical experiments. The results acquired from the electrochemical impedance spectroscopy (EIS) study showed that DPH at a concentration of 1000 ppm has a corrosion efficiency of 91.43% after 6 h immersion. The DPH molecules' orientation on the surface was assessed based on EIS predicting horizontal adsorption on the surface. Molecular simulations were done to explore the adsorption mechanism of DPH. The DPH molecules' orientation on the surface was also assessed based on computational studies confirming the horizontal adsorption predicted by EIS.

Corrosion behavior and mechanism of X80 steel in silty soil under the combined effect of salt and temperature

In this study, X80 pipeline steel was embedded in silty soil with different salinities and subjected to corrosion at a constant temperature for 24 h before electrochemical testing. The effect of soil medium, temperature, and salt content on the kinetics of corrosion behavior of X80 steel was analyzed. Furthermore, the compositions and structures of the corrosion products were analyzed by X-ray photoelectron spectroscopy and scanning electron microscopy. Based on the results, the anodic dissolution reaction mechanism of X80 steel in silty soil was determined, the differences in the corrosion process caused by different soil systems were comprehensively contrasted, and the impact of the migration process of heterogeneous silty soil on corrosion behavior under different conditions was systematically explored. Comparative analysis revealed that chloride ions possess strong adsorption ability at temperatures above freezing point and that more oxidized substances are present in the deposited layer on the surface of corroded steel, which facilitates the occurrence of corrosion under deposition. At temperatures below freezing point, the sulfate ions present in the pore solution contribute to crystallization-induced expansion and lead to swelling and deformation of the soil, rendering the X80 steel more prone to corrosion in sulfate corrosion environments.

Inhibitory Potential of New Phenolic Hydrazide-Hydrazones with a Decoy Substrate Fragment towards Laccase from a Phytopathogenic Fungus: SAR and Molecular Docking Studies

Laccase from pathogenic fungi participates in both the delignification and neutralization of phytoantibiotics. Furthermore, it interferes with the hormone signaling in plants and catalyzes melanization. Infections of these pathogens contribute to loss in forestry, agriculture, and horticulture. As there is still a need to expand knowledge on efficient defense strategies against phytopathogenic fungi, the present study aimed to reveal more information on the molecular mechanisms of laccase inhibition with natural and natural-like carboxylic acid semi-synthetic derivatives. A set of hydrazide-hydrazones derived from carboxylic acids, generally including electron-rich arene units that serve as a decoy substrate, was synthesized and tested with laccase from Trametes versicolor. The classic synthesis of the title inhibitors proceeded with good to almost quantitative yield. Ninety percent of the tested molecules were active in the range of K_I = 8–233 µM and showed different types of action. Such magnitude of inhibition constants qualified the hydrazide-hydrazones as strong laccase inhibitors. Molecular docking studies supporting the experimental data explained the selected derivatives’ interactions with the enzyme. The results are promising in developing new potential antifungal agents mitigating the damage scale in the plant cultivation, gardening, and horticulture sectors.