Synthesis, spectral properties and corrosion inhibition efficiency of new ethyl hydrogen [(methoxyphenyl) (methylamino) methyl] phosphonate derivatives: Experimental and theoretical investigation

Corrosion Inhibition of Azo Compounds Derived from Schiff Bases on Mild Steel (XC70) in (HCl, 1 M DMSO) Medium: An Experimental and Theoretical Study

The inhibitory activity of three prepared azo compounds derived from Schiff bases, namely, bis[5-(phenylazo)-2-hydroxybenzaldehyde]-4,4'-diaminophenylmethane (C1), bis[5-(4-methylphenylazo)-2-hydroxybenzaldehyde]-4,4'-diaminophenylmethane (C2), and bis[5-(4-bromophenylazo)-2-hydroxybenzaldehyde]-4,4'-diaminophenylmethane (C3), against corrosion of steel type XC70 in (HCl, 1 M DMSO) medium was investigated experimentally by electrochemical measurements and theoretically using density functional theory (DFT). The correlation between corrosion inhibition and concentration is direct. The maximum inhibition efficiency at 6 × 10^-5 M for the three azo compounds derived from Schiff bases was 64.37, 87.27, and 55.47% for C1, C2, and C3, respectively. The Tafel curves indicate that the inhibitors follow a mixed but predominantly anodic inhibitor system and have a Langmuir isothermal adsorption process. The observed inhibitory behavior of compounds was supported by DFT calculation. It was also found that there was a strong correspondence between the theoretical and experimental results.

A comprehensive assessment of carbon steel corrosion inhibition by 1,10-phenanthroline in the acidic environment: insights from experimental and computational studies

1,10-Phenanthroline (PHN) is a nitrogen-containing heterocyclic organic compound that is widely used in a variety of applications, including chemosensors, biological studies, and pharmaceuticals, which promotes its use as an organic inhibitor to reduce corrosion of steel in acidic solution. In this regard, the inhibition ability of PHN was examined for carbon steel (C48) in a 1.0 M HCl environment by performing electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), mass loss, and thermometric/kinetic. Additionally, scanning electron microscopy (SEM) was used to examine the surface morphology of C48 immersed in 1.0 M HCl protected with our inhibitor. According to the PDP tests, increasing the PHN concentration resulted in an improvement in corrosion inhibition efficiency. Besides, the maximum corrosion inhibition efficiency is about 90% at 328 K. Furthermore, the PDP assessments demonstrated that PHN functions as a mixed-type inhibitor. The adsorption analysis reveals that our title molecule mechanism is due to physical-chemical adsorption, as predicted by the Frumkin, Temkin, Freundlich, and Langmuir isotherms. The SEM technique exhibited that the corrosion barrier occurs due to the adsorption of the PHN compound through the metal/1.0 M HCl interface. In addition, the computational investigations based on a quantum calculation using density functional theory (DFT), reactivity (QTAIM, ELF, and LOL), and molecular-scale by Monte Carlo (MC) simulations confirmed the experimental results by providing further insight into the mode of adsorption of PHN on the metal surface, thus forming a protective film against corrosion on the C48 surface.

Synthesis, characterization, DFT, antioxidant, antibacterial, pharmacokinetics and inhibition of SARS-CoV-2 main protease of some heterocyclic hydrazones

Three hydrazone derivatives have been synthesized using condensation reaction of 4-hydrazinylbenzoic acid with three aromatic aldehydes namely: thiophene-2-carbaldehyde, thiophene-3-carbaldehyde and 2-furaldehyde in ethanol at 78 °C reflux. The synthesized molecules have been characterized using spectroscopic and physicochemical methods including UV-Vis, IR, ¹H NMR, ¹³C NMR, ¹⁵N NMR and melting point determination. Optimized molecular structures, UV-Vis and IR spectra modeling, the reactivity, the stability and some quantum chemical parameters of the synthesized molecules were modeled utilizing density functional theory (DFT). The obtained theoretical results were found in good agreement with the experimental results. On the other hand, the antioxidant and antibacterial activities of the molecules under study were evaluated to better understand the associated mechanisms of action specifically. Also, predicted ADME-T and pharmacokinetic parameters indicated that these compounds showed good oral bioavailability. Finally, molecular docking has been used to predict the inhibitory activity of the studied hydrazone derivatives on the SARS-CoV-2 main protease (Mpro).

Corrosion mitigation for steel in acid environment using novel p-phenylenediamine and benzidine coumarin derivatives: synthesis, electrochemical, computational and SRB biological resistivity

Three novel p-phenylenediamine and benzidine coumarin derivatives were synthetized, namely: 4,4'-((((1,4-phenylenebis(azaneylylidene))bis(ethan-1-yl-1-ylidene))bis(2-oxo-2H-chromene-3,6-diyl))bis(diazene-2,1-diyl))dibenzenesulfonic acid (PhODB), 4,4'-(((-([1,1'-biphenyl]-4,4'-diylbis(azaneylylidene))bis(ethan-1-yl-1-ylidene))bis(2-oxo-2H-chromene-3,6-diyl))bis(diazene-2,1-diyl))dibenzenesulfonic acid (BODB) and 4,4'-(((-((3,3'-dimethoxy-[1,1'-biphenyl]-4,4'-diyl)bis(azaneylylidene))bis(ethan-1-yl-1-ylidene))bis(2-oxo-2H-chromene-3,6-iyl))bis(diazene-2,1-diyl))dibenzenesulfonic acid (DODB). Their chemical structures were proved by performing Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance and mass spectrometry analysis. The synthesized p-phenylenediamine and benzidine coumarin derivatives were tested as corrosion inhibitors for mild steel (MS) in 1 M HCl solution using weight loss, electrochemical, morphological, and theoretical studies. The compound 3,3'-dimethoxy benzidine coumarin derivative (DODB) was proved to give the highest efficiency with 94.98% obtained from weight loss measurements. These compounds are mixed inhibitors, as seen by the polarization curves. Impedance diagrams showed that when the concentration of these derivatives rose, the double-layer capacitance fell and the charge transfer resistance increased. Calculated thermodynamic parameters were computed and the mechanism of adsorption was also studied for the synthesized p-phenylenediamine and benzidine coumarin derivatives. The ability of the synthesized derivatives to protect the surface against corrosion was investigated by scanning electron microscope (SEM), UV-visible spectroscopy and energy dispersive X-ray spectroscopy (EDX). Theoretical chemical calculations (DFT) and biological resistivity (SRB) were investigated.

Review of Phosphorus-Based Polymers for Mineral Scale and Corrosion Control in Oilfield

Production chemistry is an important field in the petroleum industry to study the physicochemical changes in the production system and associated impact on production fluid flow from reservoir to topsides facilities. Mineral scale deposition and metal corrosion are among the top three water-related production chemistry threats in the petroleum industry, particularly for offshore deepwater and shale operations. Mineral scale deposition is mainly driven by local supersaturation due to operational condition change and/or mixing of incompatible waters. Corrosion, in contrast, is an electrochemical oxidation–reduction process with local cathodic and anodic reactions taking place on metal surfaces. Both mineral scaling and metal corrosion can lead to severe operational risk and financial loss. The most common engineering solution for oilfield scale and corrosion control is to deploy chemical inhibitors, including scale inhibitors and corrosion inhibitors. In the past few decades, various chemical inhibitors have been prepared and applied for scaling and corrosion control. Phosphorus-based polymers are an important class of chemical inhibitors commonly adopted in oilfield operations. Due to the versatile molecular structures of these chemicals, phosphorus-based polymeric inhibitors have the advantage of a higher calcium tolerance, a higher thermal stability, and a wider pH tolerance range compared with other types of inhibitors. However, there are limited review articles to cover these polymeric chemicals for oilfield scale and corrosion control. To address this gap, this review article systematically reviews the synthesis, laboratory testing, and field applications of various phosphorus-based polymeric inhibitors in the oil and gas industry. Future research directions in terms of optimizing inhibitor design are also discussed. The objective is to keep the readers abreast of the latest development in the synthesis and application of these materials and to bridge chemistry knowledge with oilfield scale and corrosion control practice.

Innovative Method for Longer Effective Corrosion Inhibition Time: Controlled Release Oil Palm Empty Fruit Bunch Hemicellulose Inhibitor Tablet

This study aims to develop a controlled release oil palm empty fruit bunch hemicellulose (EFB-H) inhibitor tablet for mild steel in 1 M HCl. As plant extracts tend to deteriorate at longer immersion time, limiting its industrial applicability, we attempted to lengthen the inhibition time by forming a controlled release inhibitor tablet. Electrochemical methods (potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS)) were employed to investigate the efficiency and mechanism of the inhibition. An optimum dosage and immersion time was determined via Response Surface Methodology (RSM). EFB-H tablet was formulated using D-optimal mixture design, and its anticorrosion action at extended immersion time was compared with EFB-H powder. PDP measurement revealed that EFB-H is a mixed type inhibitor. RSM optimization unveiled that the optimum point for a maximum inhibition efficiency (87.11%) was at 0.33 g of EFB-H and 120 h of immersion time. Tablet T3 with EFB-H to gum Arabic to hydroxypropyl methylcellulose ratio of 66:0:34 portrayed the best tensile strength (0.243 MPa), disintegration time (152 min) and dissolution behavior. EFB-H tablet exhibited a longer-lasting inhibition effect than powder, which was 360 h as compared to 120 h for powder. Overall, EFB-H tablet has been successfully developed, and its enhanced effective inhibition time has been experimentally proven.

New α-Hydrazinophosphonic acid: Synthesis, characterization, DFT study and in silico prediction of its potential inhibition of SARS-CoV-2 main protease

A new α-Hydrazinophosphonic acid (HDZPA) has been synthesized and its molecular structure was determined using spectroscopic methods. The Density Functional Theory (DFT) at the B3LYP/6-31 G (d,p) level was utilized to determine the electronic properties, vibrational modes and active sites of the examined molecule. In this context, some quantum chemical parameters have been calculated in order to discuss the reactivity of the studied molecule. Also, the inhibition activity of the investigated α-Hydrazinophosphonic acid for SARS-CoV-2 main protease (M^pro) and RNA dependent RNA polymerase (RdRp) has been predicted using in silico docking.

Corrosion inhibiting effect of a green formulation based on Opuntia Dillenii seed oil for iron in acid rain solution

This study examines the development of a new green and eco-friendly formulation derived from Opuntia dillenii seed oil (labeled as FOD) and its application as a corrosion inhibitor to protect iron which is subject to corrosion phenomena that become important especially in acidic environments as acid rain.

Physicochemical properties and fatty acid analysis of Opuntia dillenii seed oil were performed and they demonstrated that the oil is a major source of unsaturated fatty acids, in particular linoleic acid, with a percentage of 73.388%.

Corrosion inhibition effect of FOD was studied by gravimetric methods, electrochemical measurements, and scanning electron microscopy coupled with elemental analysis (SEM/EDX). Obtained results confirmed that FOD behaves as a good mixed corrosion inhibitor with predominant anodic activity. Inhibition efficiency of FOD is more important when the concentration of FOD and the immersion time increase, reaching values up to 99%. FOD forms a barrier layer on the surface of the iron, and thereby minimizes the contact area between the metal surface and the corrosive solution. The adsorption behavior of FOD on iron surface obeys Langmuir adsorption isotherm with chemisorption and physisorption mechanism.

Adlay seed hull polysaccharide as a green corrosion inhibitor for mild steel in acid solution: surface analyses and theoretical calculations

Adlay seed hull polysaccharide was developed here as a green corrosion inhibitor for mild steel in 1 M HCl solution, and its inhibition effect was studied with electrochemical experiments, theoretical calculations, etc.

1H-Benzimidazole-5-carboxamidine derivatives: design, synthesis, molecular docking, DFT and antimicrobial studies

15 new 1H-benzimidazole-5-carboxamidine derivatives were synthesized, their antimicrobial effects were evaluated, and molecular docking and DFT studies were performed.

Synthesis, characterization, and utilization of a diallylmethylamine-based cyclopolymer for corrosion mitigation in simulated acidizing environment

A novel random copolymer 4, containing diallylmethylamine and N¹,N¹-diallyl-N¹-methyl-N⁶,N⁶,N⁶-tripropylhexane-1,6-diammonium dibromide units in a 1:1 ratio (polymer 4) was synthesized via Butler's cyclopolymerization technique. Characterization was accomplished by ¹H NMR, elemental analysis, and Fourier-transform infrared spectroscopy (FTIR). Polymer 4 was tested as corrosion inhibitor for low carbon steel in 15% HCl solution via gravimetric and electrochemical approaches. The analysis of the metal specimen surfaces was done using scanning electron microscope (SEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDAX), and X-ray photoelectron spectroscopy (XPS) methods. Polymer 4 is inhibitor for the substrate particularly at elevated temperatures. Corrosion mitigation is by chemisorption mechanism and can be best described with the Langmuir and El-Awady et al. kinetic-thermodynamic adsorption isotherms. Polymer 4 corrosion mitigation capacity can be improved by the addition of a minute amount of I^- ions. Inhibition efficiency of 92.99% has been achieved with 500 ppm polymer 4 + 1 mM KI mixture at 25 °C. Surface analysis results support the claim of adsorption of additive molecules on steel surface. From XPS results, corrosion products on steel surface exposed to the free acid solution are mixtures of chlorides, carbonates, oxides, and hydroxides. In polymer 4 + KI system, polymer 4 molecules are adsorbed on triiodide and pentaiodide ions layer. The improved corrosion inhibition of polymer 4 by I^- ions is synergistic in nature according to calculated synergism parameter. Polymer 4 is a promising corrosion inhibitor for oil well acidizing purpose.

Surface protection of X80 steel using Epimedium extract and its iodide-modified composites in simulated acid wash solution: a greener approach towards corrosion inhibition

The pure extract of Epimedium (EPM) was investigated as an alternative anticorrosion additive for acid wash and descaling solution simulated using 5% HCl.