Corrosion inhibition of mild steel in hydrochloric acid by some pyridine derivatives: An experimental and quantum chemical study

Frontiers and advances in N-heterocycle compounds as corrosion inhibitors in acid medium: Recent advances

The acid solution is widely used in chemical cleaning, oil well acidifying, and other fields, which also brings the problem of metal corrosion that cannot be underestimated. However, adding an inhibitor is one of the most convenient and effective ways to slow down metal corrosion. N-heterocyclic compounds with high stability and durability, in line with the strategy of sustainable development, have been widely studied in an acidic environment. Imidazole, pyridine, and quinoline compounds, as the most commonly used corrosion inhibitors, can form a compact protective film via π electron cloud shifting towards the N atoms to generate coordination function. In particular, flexible modifiability makes N-heterocyclic compounds adapt to different corrosion environments readily, conducive to the formation of chemical bonds between compounds with metal surfaces to be better adsorption, so as to avoid the blemish of traditional inhibitors (such as inorganic salt and organic amines inhibitors) due to excessive usage, surface roughness of metal or environmental factor (for instance, temperature, pH and metallic) causing loose bonding between film and metal surface. More importantly, the efficient corrosion inhibition and toxicity of N-heterocyclic compounds have close to do with their own functional groups. Combined with the latest research achievement, the effects of different substituents on the corrosion inhibition and corrosion inhibition mechanisms were systematically reviewed in the acid-corrosive solution of imidazole, pyridine, and quinoline and their derivatives in this review article, respectively. In addition, the application and function of density functional theory in predicting the corrosion inhibition effect of corrosion inhibitors are also discussed. The future development trend was prospected according to the summarized research results.

Corrosion inhibition properties of schiff base derivative against mild steel in HCl environment complemented with DFT investigations

There is growing interest in using corrosion inhibitors and protective treatments to limit the degradation of mild steel, leading to the development of numerous Schiff bases as cutting-edge inhibitors. In this study, the effectiveness of a Schiff base, 3-((5-mercapto-1,3,4-thiadiazol-2-yl)imino)indolin-2-one (MTIO), to prevent mild steel corrosion in HCl was investigated using weight loss measurements, potentiodynamic polarization measurements, electrochemical impedance spectroscopy techniques, and surface characterization. The experimental results showed that 0.5 mM MTIO exhibited a satisfactory inhibitor efficiency of 96.9% at 303 K. The MTIO molecules physically and chemically adsorbed onto the mild steel surface following the Langmuir model, forming a compact protective film attributed to the presence of a thiazole ring in the MTIO structure. Theoretical calculations were combined with experimental techniques to investigate the anticorrosion performance and mechanism of inhibition.

Experimental and computational approaches of methoxy naphthylbithiophene derivatives and their use as corrosion protection for carbon steel in acidic medium

The inhibition efficiency and adsorption affinity were investigated for two novel compounds, namely: 6-methoxy-2-naphthyl-[2, 2'-bithiophene]-5-carboxamidine hydrochloride salt (MA-1440) and 5'-(4-chlorophenyl)-2, 2'-bifuran-5-carboxamidine hydrochloride salt (MA-1456). The inhibition study was conducted on carbon steel surface in 1.0 M HCl with different inhibitor doses and different temperature levels, to investigate the optimum dose and preferable temperature. The performed investigation included chemical, electrochemical, instrumental, and quantum computation techniques. A chemical technique was accomplished by using weight-loss measurements. Different factors were studied using weight-loss measurements in order to reach the maximum inhibition efficiency. The adsorption study revealed that the examined inhibitors obey the Langmuir adsorption isotherm and are chemically adsorbed on the steel surface. The electrochemical measurements were accomplished through the electrochemical impedance (EIS) and potentiodynamic polarization (PDP) techniques. Based on the electrochemical measurements, the examined compounds were categorized as mixed inhibitors. The instrumental examination using different techniques namely: scanning electron microscope (SEM), energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) confirmed that the considered inhibitors are excellently adsorbed over the carbon steel surface. The extent of the adsorption affinity of these compounds on the carbon steel surface was studied theoretically using quantum computations and Monte Carlo simulation. The theoretical investigation results of quantum chemistry were validated with those obtained by chemical and electrochemical methodologies. All investigations prove that, the tested compounds were adsorbed chemically on the steel surface and achieved maximum inhibition efficiency of, 94.69% and 90.85% for M-1440 and MA-1456, respectively, at the optimum concentration 30 [Formula: see text] 10^-6 mol L^-1 and temperature 328 K.

Unraveling Bonding Mechanisms and Electronic Structure of Pyridine Oximes on Fe(110) Surface: Deeper Insights from DFT, Molecular Dynamics and SCC-DFT Tight Binding Simulations

The development of corrosion inhibitors with outstanding performance is a never-ending and complex process engaged in by researchers, engineers and practitioners. The computational assessment of organic corrosion inhibitors' performance is a crucial step towards the design of new task-specific materials. Herein, the electronic features, adsorption characteristics and bonding mechanisms of two pyridine oximes, namely 2-pyridylaldoxime (2POH) and 3-pyridylaldoxime (3POH), with the iron surface were investigated using molecular dynamics (MD), and self-consistent-charge density-functional tight-binding (SCC-DFTB) simulations. SCC-DFTB simulations revealed that the 3POH molecule can form covalent bonds with iron atoms in its neutral and protonated states, while the 2POH molecule can only bond with iron through its protonated form, resulting in interaction energies of -2.534, -2.007, -1.897, and -0.007 eV for 3POH, 3POH⁺, 2POH⁺, and 2POH, respectively. Projected density of states (PDOSs) analysis of pyridines-Fe(110) interactions indicated that pyridine molecules were chemically adsorbed on the iron surface. Quantum chemical calculations (QCCs) revealed that the energy gap and Hard and Soft Acids and Bases (HSAB) principles were efficient in predicting the bonding trend of the molecules investigated with an iron surface. 3POH had the lowest energy gap of 1.706 eV, followed by 3POH⁺ (2.806 eV), 2POH⁺ (3.121 eV), and 2POH (3.431 eV). In the presence of a simulated solution, MD simulation showed that the neutral and protonated forms of molecules exhibited a parallel adsorption mode on an iron surface. The excellent adsorption properties and corrosion inhibition performance of 3POH may be attributed to its low stability compared to 2POH molecules.

Investigation of synthesized ethyl-(2-(5-arylidine-2,4-dioxothiazolidin-3-yl) acetyl) butanoate as an effective corrosion inhibitor for mild steel in 1 M HCl: A gravimetric, electrochemical, and spectroscopic study

The corrosion inhibition effects of five concentrations (5E-5 M to 9E-5 M) of ethyl-(2-(5-arylidine-2,4-dioxothiazolidin-3-yl) acetyl) butanoate, a novel thiazolidinedione derivative code named B1, were investigated on mild steel in 1 M HCl using gravimetric analysis, electrochemical analysis and Fourier transform infrared spectroscopy. After synthesis and purification, B1 was characterized using nuclear magnetic resonance spectroscopy. All gravimetric analysis experiments were carried out at four different temperatures: 303.15 K, 313.15 K, 323.15 K and 333.15 K, achieving a maximum percentage inhibition efficiency of 92% at 303.15 K. The maximum percentage inhibition efficiency obtained from electrochemical analysis, conducted at 303.15 K, was 83%. Thermodynamic parameters such as ΔG°_ads showed that B1 adsorbs onto the MS surface via a mixed type of action at lower temperatures, transitioning to exclusively chemisorption at higher temperatures.

Revealing the Correlation between Molecular Structure and Corrosion Inhibition Characteristics of N-Heterocycles in Terms of Substituent Groups

Controlling metal corrosion can directly address the waste of metal and the environmental pollution and resource depletion caused by metal recycling, very significant factors for green and sustainable development. The addition of corrosion inhibitors is a relatively cost-effective means of corrosion prevention. Among these, N-heterocycles have been widely used because heteroatoms contain lone pairs of electrons that can be strongly adsorbed onto metals, protecting them in highly corrosive environments at relatively low concentrations. However, due to the large variety of N-heterocycles, their corrosion inhibition characteristics have seldom been compared; therefore, the selection of appropriate N-heterocycles in the development of anti-corrosion products for specific applications was very difficult. This review systematically analyzed the influence of different substituents on the corrosion inhibition performance of N-heterocycles, including different alkyl chain substituents, electron-donating and electron-withdrawing substituents, and halogen atoms, respectively. The correlation between the molecular structure and corrosion inhibition characteristics of N-heterocycles was comprehensively revealed, and their action mechanism was analyzed deeply. In addition, the toxicity and biodegradability of N-heterocycles was briefly discussed. This study has provided a significant guideline for the development of green, promising corrosion inhibitors for advanced manufacturing and clean energy equipment protection.

Interactions study of 1,2,4-triazole derivatives in acid medium using molecular dynamics

We investigated the interaction of some 1,2,4-triazoles derivatives: 4-amino-3-methylthio-5-phenyl-4H-1,2,4-triazole 1, 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol 2 A, 4-amino-5-phenyl-2H-1,2,4-triazole-3-thione 2B, and 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol 2 C (respectively MTE 1, TL 2 A, TN 2B and TL 2 C) using the molecular dynamics simulation. First, we employed this method to predict the total energies in vacuum and in solutions (water and acid media). Then, we calculated the MD parameters: interaction energies and angle parameters. We have also evaluated the conformations of these molecules in gas and in solutions. Next, we compared the calculated results in water with those in acid solution. Our simulated results prove that the presence of intermolecular hydrogen bond increases the interaction energies in the tautomer thione 2B. We confirm that the TN 2B reaches its high stable conformation state in the solution environment. The calculations confirm that the compound MTE 1 has a spatial conformation state and shows high interaction energy in acid medium. Our molecular dynamics results complete very well our quantum chemical calculations. Communicated by Ramaswamy H. Sarma.

Corrosion protection of carbon steel by methoxy naphthylbithiophene derivatives in acidic medium: Electrochemical, surface characterization and computational approaches.. [DOI: 10.21203/rs.3.rs-2233861/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

The inhibition efficiency and adsorption affinity were investigated for two novel compounds, namely: 6-methoxy-2-naphthyl-[2, 2’-bithiophene]-5-carboxamidine hydrochloride salt (MA-1440) and 5'-(4-chlorophenyl)-2, 2’-bifuran-5-carboxamidine hydrochloride salt (MA-1456). The inhibition study was conducted on carbon steel surface in 1.0 M HCl with different inhibitor doses and different temperature levels, to investigate the optimum dose and preferable temperature. The performed investigation included chemical, electrochemical, instrumental, and quantum computation techniques. A chemical technique was accomplished by using weight-loss measurements. Different factors were studied using weight-loss measurements in order to reach the maximum inhibition efficiency. The adsorption study revealed that the examined inhibitors obey the Langmuir adsorption isotherm and are chemically adsorbed on the steel surface. The electrochemical measurements were accomplished through the electrochemical impedance (EIS) and potentiodynamic polarization (PDP) techniques. Based on the electrochemical measurements, the examined compounds were categorized as mixed inhibitors. The instrumental examination using different techniques namely: scanning electron microscope (SEM), energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) confirmed that the considered inhibitors are excellently adsorbed over the carbon steel surface. The extent of the adsorption affinity of these compounds on the carbon steel surface was studied theoretically using quantum computations and Monte Carlo simulation. The theoretical investigation results of quantum chemistry were validated with those obtained by chemical and electrochemical methodologies. All investigations prove that, the tested compounds were adsorbed chemically on the steel surface and achieved maximum inhibition efficiency of, 94.69% and 90.85% for M-1440 and MA-1456, respectively, at the optimum concentration 3010-6 mol. L-1 and temperature 328 K.

Enhancement of corrosion resistance of the cooling systems in desalination plants by green inhibitor

Taraxacum officinale extract (TOE) has been tested for preventing the corrosion of cooling systems in desalination plants. The inhibition of corrosion effects has been characterized by chemical and electrochemical methods (Mass loss, potentiodynamic polarization and electrochemical impedance spectroscopy) and surface observations. Tests on cooling systems were carried out in seawater environment. The presence of TOE in the re-circulation loop decreases the corrosion of carbon steel by adsorption of TOE compounds on the surface of metal pipes. The optimum TOE concentration was reached at 400 mg L^-1 and the inhibition efficiency was higher than 94%. TOE allowed increasing the energy barrier of the corrosion process. SEM, FT-IR and UV spectra observations confirmed that TOE prevents corrosion attacks at the surface of the pipes. HPLC analyses identified the presence of saccharides, organic acids, phenol antioxidant and caffeic acid derivatives in TOE, which may be the active promoters of corrosion inhibition.

Synthesis, Cyclic Voltammetric, Electrochemical, and Gravimetric Corrosion Inhibition Investigations of Schiff Base Derived from 5,5-Dimethyl-1,3-cyclohexanedione and 2-Aminophenol on Mild Steel in 1 M HCl and 0.5 M H2SO4

Schiff base 2,2’-(5,5-dimethylcyclohexane-1,3-diylidene)bis(azan-1-yl-1-ylidene) diphenol (DmChDp) was synthesized and characterized using spectroscopic methods (IR, UV, NMR, and Mass) and cyclic voltammetric (CV) studies. The corrosion inhibition potency of (DmChDp) on mild steel (MS) in 1M HCl and 0.5M H2SO4 was investigated. The corrosion monitoring techniques employed for this purpose are gravimetric and electrochemical methods (EIS and potentiodynamic polarization studies). The study reveals that the Schiff base, DmChDp, acts as excellent corrosion inhibitor on mild steel in 1M HCl. DmChDp obeys Langmuir adsorption isotherm both in 1M HCl and 0.5M H2SO4 on MS. Polarization studies show that DmChDp behaves as a mixed type inhibitor in both media. Scanning electron microscopic analysis established the protective nature of DmChDp on mild steel surface. The impact of temperature on the corrosion of MS was also evaluated using gravimetric method.

Corrosion Inhibition Mechanism of Mild Steel by Amylose-Acetate/Carboxymethyl Chitosan Composites in Acidic Media

This article details an investigation on the mechanism of corrosion inhibition of mild steel using amylose-acetate-blended carboxymethyl chitosan (AA-CMCh) in acidic media in the context of kinetic and thermodynamic parameters. The surface of mild steel was exposed to test solutions and evaluated using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The activation energy (Ea), free energy of adsorption (ΔG), enthalpy of activation (ΔHads), and entropy of activation (ΔSads) were determined in order to elucidate the mechanism of corrosion inhibition. The results confirmed that AA could be improved using CMCh as a corrosion inhibitor. The corrosion rate decreased from 1109.00 to 229.70 mdd (79.29%), while corrosion inhibition increased from 35.13 to 89.72%. Sulfate acid (H2SO4) of 0.25 M also helped in decreasing the corrosion rate from 2664.4 to 1041.67 mdd (60.9%) while also in increasing corrosion inhibition from 56.94 to 68.31%. The calculated values for ΔG, ΔHads, and ΔSads were −33.22 kJ·mol−1, −48.56 kJ·mol−1, and 0.0495 kJ·mol−1·K−1, respectively. The mechanism of corrosion inhibition of mild steel in the acidic condition is dominated and precipitated by the formation of the Fe-chelate compound, which was confirmed by the SEM/EDS spectrum. The reactions were spontaneous, exothermic, and irregular and takes place on the surface of mild steel.

Bispyranopyrazoles as Green Corrosion Inhibitors for Mild Steel in Hydrochloric Acid: Experimental and Theoretical Approach

In the present study, we have synthesized two novel corrosion inhibitors BP-1 and BP-2 and evaluated their corrosion inhibition property on mild steel (MS) in acid solution through weight loss and electrochemical corrosion techniques. The corrosion test results reveal that both compounds inhibit corrosion by an adsorption mechanism and display inhibition efficiency more than 95% at a low concentration of 1.72 × 10^-4 M. From the surface analysis of the protective film on MS, it was corroborated that adsorption of inhibitor molecules occurred on the MS surface through chemisorption, which further suppresses the corrosion rate. Density functional theory simulated data helps correlate the experimental trend with the theoretical study.

Targeted synthesis of cadmium(ii) Schiff base complexes towards corrosion inhibition on mild steel

Strategic synthesis of Cd(ii) Schiff base complexes with introduction of an azido ligand to achieve significant corrosion inhibition on mild steel.

Corrosion inhibition of N80 steel in 15% HCl by pyrazolone derivatives: electrochemical, surface and quantum chemical studies

The corrosion protection of N80 steel in 15% HCl using 2-(3-amino-5-oxo-4,5-dihydro-1H-pyrazol-1-yl)(p-tolyl)methyl)malononitrile (PZ-1) and 2-((3-amino-5-oxo-4,5-dihydro-1H-pyrazol-1-yl)(phenyl)methyl)malononitrile (PZ-2) has been investigated.

Green Schiff's bases as corrosion inhibitors for mild steel in 1 M HCl solution: experimental and theoretical approach

Three cysteine based Schiff bases were synthesized and their corrosion inhibition properties on mild steel in 1 M HCl solution were evaluated using weight loss and electrochemical studies and quantum chemical calculations.

Experimental and theoretical studies of triisopropanolamine as an inhibitor for aluminum alloy in 3% NaCl solution

Molecular structure of triisopropanolamine.