Gravimetric, electrochemical, and morphological studies of an isoxazole derivative as corrosion inhibitor for mild steel in 1M HCl

Adsorption studies of isoxazole derivatives as corrosion inhibitors for mild steel in 1M HCl solution: DFT studies and molecular dynamics simulation

CONTEXT

The corrosion of mild steel is a significant issue in various industries, prompting the need for effective corrosion inhibitors. This study focuses on understanding the corrosion inhibition properties of organic compounds derived from isoxazole, namely series Iso(a), Iso(b), Iso(c), Iso(d), Iso(e), Iso(f), Iso(g), and Iso(h), which could have implications for materials science and industrial applications. By investigating the influence of different substitutions on these compounds, valuable insights can be gained into designing better corrosion inhibitors for practical use.

METHODS

Theoretical studies were conducted using density functional theory (DFT) with the B3LYP functional and the 6-31G (d,p) basis set. These calculations enabled the evaluation of various parameters including frontier orbital energies (EHOMO, ELUMO), energy gap (∆E), electronegativity (χ), absolute hardness (η), softness (σ), fraction of transferred electrons (∆N), as well as local properties such as natural atomic populations and Fukui indices. Additionally, molecular dynamics simulations were performed to study the adsorption behavior of the inhibitors on the surface of Fe (110). The simulations were conducted using Materials Studio version 8.0 software package using COMPASS force field to understand the impact of different functional groups on the inhibitors before and after adsorption on the iron surface.

Inhibition of corrosion on API 5L X52 pipeline steel in acid media by Tradescantia spathacea

The concentration effect of Tradescantia spathacea (T. spathacea) as corrosion inhibitor of API 5L X52 steel in 0.5 M of H2SO4 was studied here through electrochemical and gravimetric techniques. To achieve it, samples of the material were prepared to be submitted to each of the tests. Results from electrochemical impedance spectroscopy (EIS) showed that there was an optimum concentration of the inhibitor in which is reached the maximum inhibition efficiency, displaying the best inhibition characteristics for this system with a maximum inhibition of 89% by using 400 ppm. However, the efficiency decreased until 40% when the temperature was increased to 60°C. Potentiodynamic polarization curves (PDP) revealed that some of the present compounds of T. spathacea may affect anodic and cathodic process, so it can be classified as a mix-type corrosion inhibitor for API 5L X52 in sulfuric acid. Also, this compound followed an adsorption mechanism; this can be described through a Frumkin isotherm with an adsorption standard free energy difference (ΔG°) of -56.59 kJmol-1. Metal surface was studied through scanning electron microscope, results revealed that by adding inhibitor, the metal surface is protected; also, they evidenced low damages compared with the surface with no inhibitor. Finally, Tradescantia spathacea inhibited the corrosion process with 82% efficiency.

Design, synthesis, In-vitro, In-silico and DFT studies of novel functionalized isoxazoles as antibacterial and antioxidant agents

A series of new isoxazolederivatives incorporating the sulfonate ester function has been synthesized from 2-benzylidenebenzofuran-3(2 H)-one, known as aurone. The synthesis of the target compounds was carried out following an efficient methodology that allows access to the desired products in a reproducible way and with good yield. The structures of the synthesized compounds were established using NMR (1H and 13C) spectroscopy and mass spectrometry. A theoretical study was performed to optimize the geometrical structures and to calculate the structural and electronic parameters of the synthesized compounds. The calculations were also carried out to understand the influence and the effect of substitutions on the chemical reactivity of the studied compounds. The synthesized isoxazoles were screened for their antioxidant and antibacterial activities. The findings demonstrate that the studied compounds exhibit good to moderate antibacterial activity against the tested bacteria (Staphylococcus aureus, Bacillus subtilis, and Escherichia coli). Moreover, a number of the tested isoxazole derivatives exhibit high effectiveness against DPPH free radicals. Besides that, molecular docking studies were carried out to predict binding affinity and identify the most likely binding interactions between the active molecules and the target microorganisms' proteins. A 100 ns molecular dynamics study was then conducted to examine the dynamic behavior and stability of the highly potent isoxazole 4e in complex with the target bacterial proteins. Finally, the ADMET analyses suggest that all the synthesized isoxazoles have good pharmacokinetic profiles and non-toxicity and non-carcinogenicity in biological systems.

New benzisoxazole derivative: A potential corrosion inhibitor for mild steel in 0.5 M hydrochloric acid medium -insights from electrochemical and density functional theory studies

6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole. HCl (FPBH), a substituted benzisoxazole derivative, was prepared from isonipecotic acid and characterized using various spectroscopic techniques. Using electrochemical examinations such as potentiodynamic polarisation (PDP) and electrochemical impedance spectroscopic (EIS) technique, the corrosion mitigation capabilities of this compound for mild steel (MS) in 0.5 M HCl medium were investigated. Theoretical studies were performed using quantum chemical calculations and density functional theory (DFT). PDP results exhibited the mixed-type behavior of FPBH and showed a maximum efficiency of 94.5 % at 1 × 10-3 M. The development of a protective adsorbed layer of FPBH decreases the corrosion current density (icorr) and corrosion rate (CR). The EIS technique revealed that the rise in the charge transfer resistance (Rct) values and reduction in the thickness of the double-layer capacitance (Cdl) reflected the drop in corrosion rate. The adsorption of FPBH took place through physisorption by conforming Langmuir's isotherm. The DFT method was performed on the optimized structure of FPBH to get additional evidence on the action mode of FPBH with the metal surface.

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.

A green protocol for the one-pot synthesis of 3,4-disubstituted isoxazole-5(4H)-ones using modified β-cyclodextrin as a catalyst

This manuscript reports an impressive and facile strategy for synthesizing isoxazole derivatives using immobilized Cu (I) in metformin-functionalized β-cyclodextrin as a catalyst. The architecture of this catalyst was characterized by different analytical techniques such as Fourier transform infrared spectroscopy, Thermogravimetric analysis, X-ray diffraction, Field emission scanning electron microscopy, and Energy-dispersive X-ray spectroscopy. The catalyst showed remarkable reusability even after 7 consecutive runs.

A Brief Review on Fruit and Vegetable Extracts as Corrosion Inhibitors in Acidic Environments

The corrosion of metals, i.e., the initiation and acceleration of the surface deterioration of metals through an electrochemical reaction with the surrounding intrusive environment, is a global concern because of the economic and environmental impacts. Corrosion inhibitors are considered the most practical choice among the available corrosion protection techniques due to their effectiveness in terms of functionality and cost. The use of traditional and toxic corrosion inhibitors has led to environmental issues, arousing the need for green counterparts that are environmentally friendly, easily accessible, biodegradable, and cost-effective. In this review, the utilization of green corrosion inhibitors purely acquired from renewable sources is explored, with an in-depth focus on the recent advancements in the use of fruit and vegetable extracts as green corrosion inhibitors. In particular, fruits and vegetables are natural sources of various phytochemicals that exhibit key potential in corrosion inhibition. To shed light on the true potential of such extracts in the protection of steel in acidic environments, the experimental techniques involved in corrosion inhibition and the mechanism of corrosion inhibition are discussed in detail. The study highlights the potential of fruit and vegetable extracts as non-toxic, economical, and effective corrosion inhibitors in the pursuit of green chemistry. In addition to discussing and outlining the current status and opportunities for employing fruit and vegetable extracts as corrosion inhibitors, the current review outlines the challenges involved in the utilization of such extracts in corrosion inhibition.

One-Pot Hydrothermal Synthesized Nitrogen and Sulfur Codoped Carbon Dots for Acid Corrosion Inhibition of Q235 Steel

N and S codoped carbon dots having good water solubility have been successfully made by a novel hydrothermal method and characterized by FTIR, XPS, and TEM. The as-synthesized CDs were carbon particles rich in polar functional groups less than 10 nm in size. Electrochemical measurements, gravimetry, and surface analysis methods were utilized to examine the inhibition characteristics and adsorption mechanism of CDs on the carbon steel in acid pickling solutions. Electrochemical measurements verified that the CDs displayed adequate protection with high inhibition efficiency of 97.8%. The long-term weight-loss experiments up to 72 h further confirmed the excellent corrosion inhibition at room temperature and 313 K. The results presented are helpful for the formulation of more effective acid pickling corrosion inhibitors.

Organic Compounds as Corrosion Inhibitors for Carbon Steel in HCl Solution: A Comprehensive Review

Most studies on the corrosion inhibition performance of organic molecules and (nano)materials were conducted within “carbon steel/1.0 M HCl” solution system using similar experimental and theoretical methods. As such, the numerous research findings in this system are sufficient to conduct comparative studies to select the best-suited inhibitor type that generally refers to a type of inhibitor with low concentration/high inhibition efficiency, nontoxic properties, and a simple and cost-economic synthesis process. Before data collection, to help readers have a clear understanding of some crucial elements for the evaluation of corrosion inhibition performance, we introduced the mainstay of corrosion inhibitors studies involved, including the corrosion and inhibition mechanism of carbon steel/HCl solution systems, evaluation methods of corrosion inhibition efficiency, adsorption isotherm models, adsorption thermodynamic parameters QC calculations, MD/MC simulations, and the main characterization techniques used. In the classification and statistical analysis section, organic compounds or (nano)materials as corrosion inhibitors were classified into six types according to their molecular structural characteristics, molecular size, and compound source, including drug molecules, ionic liquids, surfactants, plant extracts, polymers, and polymeric nanoparticles. We outlined the important conclusions obtained from recent literature and listed the evaluation methods, characterization techniques, and contrastable experimental data of these types of inhibitors when used for carbon steel corrosion in 1.0 M HCl solution. Finally, statistical analysis was only performed based on these data from carbon steel/1.0 M HCl solution system, from which some conclusions can contribute to reducing the workload of the acquisition of useful information and provide some reference directions for the development of new corrosion inhibitors.

Application of surfactants as anticorrosive materials: A comprehensive review

Corrosion is the degradation of a metal due to its reaction with the environment. One of the most efficient ways of securing metal surfaces from corrosion is the use of corrosion inhibitors. Their efficacy is connected to their chemical composition, their molecular structures, and their adsorption affinities on the metal surface. This review article focuses on the prospects of different types of monomeric and gemini surfactants, mixed surfactants systems, surfactants- additives mixed systems, inhibitors-surfactants (as additives) mixed systems, and ionic liquid based surfactants as promising corrosion-inhibiting formulations in the aqueous phase and the role of surfactants in developing protective coatings. The analysis starts with an accurate overview of the characteristics, types, and structure-property-performance relationship of anti-corrosion formulations of such inhibitors.