Anticorrosion Activity Research Articles

Synthesis, Corrosion Inhibition, In Silico ADME, DFT, and Antibacterial Activity of Pyridine‐Based Schiff Base and Its Cu (II) Complex

ABSTRACTHerein, we report the synthesis of an (E)‐N‐(pyridine‐3‐ylmethylene)pyridine‐2‐amine Schiff base (ENppa) and its Cu (II) complex (Cu‐ENppa) using 2‐aminopyridine (2APy) and pyridine‐3‐carbaldehyde (P3C). This study aimed to investigate the ADMET profiles, electronic features, antibacterial and anticorrosion activities of the synthesized ligand, and its Cu (II) complex. The compounds were characterized using various techniques, including CHN analysis, FT‐IR, 1H and 13C NMR, MALDI‐TOF MS, ICP‐MS, SEM, TGA/DTA, UV–visible spectroscopy, and powder X‐ray diffraction (PXRD). The Cu (II) ion exhibited tetrahedral geometry in the complex by coordinating with two nitrogen atoms, one from an imine group and the other from a pyridine ring. UV–visible spectroscopy and magnetic moment data also supported this geometry. TGA/DTA revealed three stages of decomposition at 141°C°C–255°C, 255°C°C–367°C, and 549°C°C–659°C, with CuO as the final residue. PXRD analysis identified ENppa and Cu‐ENppa as nanocrystallites, with crystallinities of 82% and 49%, respectively. Both compounds were highly effective in inhibiting mild steel corrosion in acidic media, with inhibition efficiencies of 97% and 98%, respective for Cu‐ENppa and ENppa. They also exhibited favorable ADME profiles, indicating potential as drug candidates for in silico ADME studies. The antibacterial activity results demonstrated promising efficacy, with Cu‐ENppa showing higher activity than ENppa.

Investigation of the Anticorrosive Activity of Piper divaricatum Essential Oil on Steel in 1 M HCl.

Piper divaricatum essential oil (PDEO), extracted from plants of the Brazilian Amazon, was investigated for the first time as a novel green or eco-friendly inhibitor for steel corrosion in 1 M HCl at 25 °C. Our electrochemical studies demonstrate that for different PDEO concentrations, lower E corr and i corr values were obtained. The influence of the oil concentration on corrosion inhibition, 0.5-4 g/L, was determined for 1 and 7 days of immersion. The corrosion rate (CR) and inhibition efficiency (IE) were determined by mass loss. The steel surface in the presence and absence of oil was investigated by scanning electron microscopy (SEM). The main PDEO compounds, determined by gas chromatography-mass spectrometry (GC-MS), were methyleugenol (20.68%) and eugenol (15.42%). The CR and IE for 2 g/L PDEO exhibited an optimal value of 4.31 mm/year and 98.3% for 7 days of immersion, respectively. The surface with 2 g/L oil for 7 days exhibited a less rough morphology, which was attributed to the corrosion inhibitory effect of PDEO. In addition, the PDEO adsorption process on the steel surface obeyed the Langmuir isotherm model. Negative values found for free standard energy ( < 0 kJ·mol-1) were attributed as a favorable process, i.e., an indicative of physisorption and chemisorption between the PDEO components and the steel surface. Our results reveal that the PDEO has a promising character for anticorrosive steel applications and metal coating in industries.

Improved Interfacial Interactions by Core-Shell CoFe2O4@SiO2 Composites to Enhance the Ability of Corrosion Resistance and Electromagnetic Wave Absorption.

With the rapid development of science and technology, stealth and anti-corrosion activities in oceans have attracted widespread attention. This study successfully prepares CoFe2O4@SiO2 with a core-shell structure. This core-shell structure endows the CoFe2O4@SiO2 with good impedance matching and interfacial polarization. Thus, the CoFe2O4@SiO2 exhibits an excellent electromagnetic wave absorption performance with a minimum reflection loss of -45.16dB. Moreover, the CoFe2O4@SiO2 exhibits an excellent dispersion ability in epoxy. The corrosion resistance of the CoFe2O4@SiO2/epoxy is enhanced. After 60 days of immersion, the low-frequency impedance modulus of the CoFe2O4@SiO2/epoxy is still >109Ωcm2. The CoFe2O4@SiO2 realize the dual functions of stealth and anti-corrosion, which provide ideas for developing marine stealth applications.

Enhancing structural durability in marine concrete piles with initial defects: RS-AAT-induced advection to suppress chloride ion penetration

Chlorine-induced corrosion in unsaturated, cracked, and delaminated reinforced concrete structures is a major cause of lifespan decline in marine wet and dry zones. Reverse-seepage and Saturation based Active Anti-corrosion Technology (RS-AAT) has the scientific basis and application potential to solve this problem due to its unique saturation and reverse-seepage effects provided by structural construction means. This study introduces an analytical framework for understanding time-dependent chloride ion permeation in concrete pipe piles, incorporating the combined impact of cracks, delamination, and RS-AAT anti-corrosion approach. The analytical approach is validated through finite element method simulations and a comprehensive 90-day indoor experiment, which simulate marine submerged and tidal conditions. Extensive parametric analysis further elucidates advection-induced suppression of chloride ion diffusion by RS-AAT in cracked and delaminated conditions, considering chloride ion diffusion coefficient and water permeability coefficient, reverse-seepage pressure, initial crack characteristics and centrifugal stratification. Results show that RS-AAT substantially inhibits chloride ion penetration and lengthens the lifespan of concrete piles, even initially cracked or delaminated. This work provides a basis for RS-AAT’s application and optimization as an innovative approach to enhancing marine concrete infrastructure.

Self-passivation/self-delivery/self-healing anticorrosion polymer coating for marine applications

Corrosion of steel in the marine environment greatly reduces their service life. Polymeric coatings are the most popular anticorrosion technology, but seawater penetration cannot be prohibited because of the distinct stacking structure of the macromolecular chains. In this context, a novel anticorrosive hyperbranched polyurethane-based coating with dopamine (DOPA) at the terminals is prepared herein. The built-in DOPA is able to capture the iron ions released from the corroded substrate and form DOPA-Fe3+ complexation, which further cooperates with the surrounding seawater and imparts self-passivation, self-delivery and self-healing capabilities to the coating. Under the joint action of these measures, the corrosion of tinplate (serving as the steel model) is reduced to a record-low level (corrosion current = 1 × 10−9 A cm−2, corrosion rate = 1 × 10−5 mm year−1). Conceptually, the present dynamic active anticorrosion strategy greatly outperforms the traditional static passive approach, and turns the unfavorable but unavoidable seawater into a favorable factor, which paves the way for the development of long-lasting marine coatings.

Anticorrosive activity of Melothria perpusilla: A renewable and sustainable inhibitor

Anticorrosive activity of Melothria perpusilla extract on mild steel in H2SO4 was examined by weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy methods. The results revealed that mild steel corrosion was effectively controlled by the extract with 99.4 % efficiency at 3000mg/L concentration. The efficiency was improved with higher extract concentration but decreased as the temperature increased. The Tafel plots and its corrosion potential value (<85 mV) inferred that Melothria perpusilla acts as a mixed type inhibitor. Adsorption of phytochemicals onto the surface of mild steel is the primary factor in reducing corrosion. The increase in activation energy for adsorption from 22.73 kJ mol−1 in acid to 133.74 kJ mol−1 in extract's presence confirms the active role of phytochemicals in adsorption process. The increase in charge transfer resistance from 3.21 Ω cm2 in acid to 369.2 Ω cm2 in extract's presence, coupled with a decrease in double layer capacitance in the EIS investigation, suggests that a charge transfer mechanism is active at the mild steel-solution interface. Gas chromatography-Mass spectroscopy revealed the presence of five major phytochemicals along with other organic compounds in the extract. Fourier transform infrared and UV–visible spectroscopies indicated the active functional moieties (-COOH, –CONH2, -C-O-C-, –C=C- and long chain alkyl groups) are involved in the inhibition. Scanning electron microscopy confirmed the existence of shielding film of phytochemicals on mild steel. Density functional theory validated the inhibitory properties of the constituents. Therefore, it is concluded that Melothria perpusilla is an efficient green inhibitor in acidic condition.

Investigation of the energy gap and anti-corrosion activities of triethanolamine lauryl sulfate for carbon steel in 1.0 M HCl using DFT theory and electrochemical studies

Corrosion inhibition is a critical strategy in the industry to mitigate the detrimental effects of corrosion. Green inhibitors are a concern and are encouraged to apply in various ways. Triethanolamine lauryl sulfate (TLS) investigates as a green corrosion inhibition for carbon steel in 1 M HCl using weight loss and electrochemical measurements. A weight loss study revealed that 100 μM of TLS had the highest inhibition effectiveness of 95.7 %. Tafel estimations from the polarization profiles showed that 100 μM had an optimal inhibition effectiveness of about 96.3 %. The physical adsorption of TLS on the carbon steel surface, which followed the Langmuir adsorption isotherm, was ascribed to the inhibitive effect. The results declare that TLS functioned as an inhibitor of mixed types. For TLS, the adsorption Gibb's free energy is −19.6 kJ mol−1, indicating spontaneous and physisorption-based. The energy gap of TLS is evaluated theoretically using density functional theory (DFT), and a lower value indicates its great donation ability of electron’s to the carbon steel. The mechanism of adsorption of TLS onto the metal surfaces is illustrated in terms of experimental and theoretical calculations.

Verbena officinalis (VO) leaf extract as an anti-corrosion inhibitor for carbon steel in acidic environment

In the present work, Verbena Officinalis (VO) leaf extract was used as potential corrosion inhibitor for the corrosion of carbon steel (CS) in 0.5 M H2SO4 medium. Further, the corrosion inhibiting nature of VO leaf extract towards the CS was evaluated using mass loss (ML), potentiodynamic polarization (PDP), electrical impedance spectroscopy (EIS) and surface morphological analyses using atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS) techniques. Calculation of activation energy Ea∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\left( {{\ ext{E}}_{{\ ext{a}}}^{*} } \\right)$$\\end{document} using Arrhenius equation shows the increase in activation energy when adding the VO leaf extract in 0.5 M H2SO4 medium and the maximum activation energy (Ea∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{E}}_{{\ ext{a}}}^{*}$$\\end{document} = 49.9 kJ mol−1) was observed for 1000 mg L−1 VO leaf extract in acid medium. The negative free energy values suggested the spontaneous and the stability of the adsorbed layer of VO leaf extract on the CS surface. Using EIS measurements, high percent inhibitory effectiveness of 91.1% for 1000 ppm solutions was achieved. With an increase in VO leaf extract dose, the double layer capacitance (Cdl) values fall while the values of charge transfer (Rct) increase. This showed that a protective layer of VO leaf extract on CS surface was formed. The polarization curves showed that the VO leaf extract acts as a mixed-type inhibitor. It is discovered that the adsorption of VO leaf extract molecules adhering to the CS surface followed the Langmuir isotherm. The anti-corrosion action of VO leaf extract is fully demonstrated by some surface techniques.

Facile synthesis, corrosion inhibition, adsorption and DFT studies of 2-(4-(methylsulfanyl) phenyl) −4, 5-diphenyl-1H-imidazole for mild steel in acidic environment

A green, solvent-free, cost effective one-pot synthesis method is employed to produce the innovative corrosion-inhibiting compound 2-(4-(methylsulfanyl)phenyl)-4,5-diphenyl-1H-imidazole (MDPI). The molecular structure of MDPI can be identified using CHN analyses, FT-IR, 1H and 13C NMR spectra. Various electrochemical and gravimetric techniques are utilized to evaluate the anti-corrosion properties of MDPI. The results indicate that MDPI effectively inhibits the corrosion of mild steel under all tested conditions. At 306 K, MDPI achieved a maximum corrosion inhibition efficiency of 98.01 % at a concentration of 10 mM. MDPI exhibited strong adsorption and excellent anti-corrosion properties, forming a protective layer on the mild steel surface. The Langmuir adsorption isotherm, with a ΔGoads value of −39.55 kJ/M was found to be more suitable for this study, indicating that the process occurred by physisorption. Tafel curves indicated that MDPI functions as a mixed-type corrosion inhibitor. Surface characteristics were analyzed using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and atomic force microscopy (AFM). Quantum chemistry studies revealed a HOMO-LUMO energy gap of 3.926 eV, corroborating the anti-corrosion effectiveness of MDPI in hydrochloric acid solution. MDPI exhibited promising anti-corrosion activity due to its heterocyclic ring containing nitrogen heteroatoms as well as a methylsulfanyl functional group.

Covalent electrografting of aryl groups on AA2060-T8 surfaces, and their modification with Ce(4OHcin)3 to incorporate additional anticorrosive activity

The aluminum alloys used in aerospace applications are susceptible to corrosion. This has led to the development of methodologies that ensure the durability of the parts and pieces of aircraft. These anticorrosive processes involve the use of coatings containing chromate-based corrosion-inhibitor compounds. Although these coatings provide an excellent solution to this problem, their use in protection protocols is restricted owing to their high toxicity and carcinogenic nature.This study evaluates a different process to protect aluminum alloy surfaces that incorporates the derivatization of organic compounds using potentiostatic techniques. The metallic surface was modified in situ by the potentiostatic reduction of aryl diazonium salts, leaving the surface covered with molecular grafts. The grafting of molecules onto the surface is modulated by the application of a potential that causes the formation of aryl radicals. The organic compound selected in this study was p-toluidine in protic medium. The derivatization process in the AA2060-T8 alloy was carried out at different pHs and potentials, observing from the potential/current responses in 0.1 M NaCl solution that the maximum optimization is obtained at pH 3 and -1 V.Likewise, the E/I and electrochemical impedance (EIS) responses of the electrografted samples modified and functionalized with cerium 4-hydroxycinnamate (Ce(4-OHcinn)3) revealed that the presence of this compound in the arylic structure significantly increased the protective capacity of the organic film electrografted on the aluminum alloy.The morphologies and characteristics of the modified surface were studied by SEM, TEM, and XPS. Furthermore, TEM examinations of ultramicrotomed sections of the electrografted specimens revealed the presence of a film approximately 10 nm thick on the AA2060-T8 surface.

Synthesis and anticorrosion properties of N-aryl-N1-pyridylthioureas and their benzylated products

N-Phenyl-, 1- and 2-naphthyl-N1-2- and 4-pyridylthioureas were synthesized via the reaction of phenyl-, 1- and 2-naphthylisothiocyanates with 2- and 4-aminopyridines, and the corresponding pyridine salts were prepared by benzylation of the latter. The anticorrosive properties of the synthesized compounds were studied by the gravimetric method in 3 M HCl at 800C using the 08 kp steel samples. The introduction of a benzyl fragment into the structure of N-aryl-N1-pyridylthioureas led to the emergence of a new adsorption ammonium center, which increased the overall anti-corrosion efficiency of the obtained compounds. When using N-aryl-N1-pyridylthioureas, the corrosion inhibition coefficient had the values of 4.5 to 59.0, whereas it increased to 90.8-629.0 for their salts. To explain the different anti-corrosion activity of N-aryl-N1-pyridylthioureas and their pyridine salts, quantum-chemical calculations of the energy parameters ЕНОМО, ЕLUMO and Е=ЕLUMO–EHOMO were carried out and the dependences of the corrosion inhibition coefficients on EHOMO and E, eE were obtained. A correlation was established between the inhibitory efficiency and energy parameters of the studied compounds.

RS-AAT for enhancing saturation and chloride resistance in unsaturated concrete: Experimental and numerical assessment

In this paper, the effect of RS-AAT (Reverse-seepage and Saturation based Active Anti-corrosion Technology) on chloride ion erosion and saturation of unsaturated concrete is studied. The design of partially opening of permeable pipes is proposed for partial purpose. The infiltration of chloride ions in cylindrical concrete by RS-AAT is experimentally and numerically analyzed. Based on the water vapor adsorption and adsorption isotherm test and chloride ion erosion test, a convection-diffusion model of chloride ions with varying saturation is established by using simultaneous V-G model and Richards' equation. It can be used for characterizing the effect of pore opening on saturation change and chloride ion erosion. The results show that the use of RS-AAT can accelerate the growth of concrete saturation in the alternating wet and dry zones, and keep the area in a saturated state, under the effect of reverse seepage and saturation, the durability of the structure is increased. Moreover, the opening size and spacing of the permeable pipe are especially investigated. The results recommend 8 mm opening diameter and 2 mm opening spacing, by which the opening spacing is reduced as much as possible, and the ability to resist chloride ion erosion for a long time can be improved s under the combined action of reverse seepage and saturation. The significance of these results is immense for the continued utilization of the novel anti-chloride attack technology in engineering applications.

PH-responsive anti-corrosion activity of gallic acid-intercalated MgAl LDH in acidic, neutral, and alkaline environments

Undoubtedly, designing pH-responsive particles is one of the most fascinating aims for corrosion experts. Local pH variations can occur through the corrosion process (chemical and electrochemical reactions), accelerating the corrosion rate. However, by designing this class of modern inhibitors, a significant part of the effects of pH variation during corrosion disappears. Herein, a novel layer double hydroxide-based (LDH) nanocomposite, which is filled by gallic acid (GA) molecules, was designed. To prove the composite inhibition proficiency, EIS tests were conducted in acid, neutral and alkaline atmospheres and then surface morphology of the protected and unprotected samples are visualized by FE-SEM images. Simultaneously, the EDS-Mapping technique was applied to predict the elemental composition of the generated inhibitive layer. The results of the EIS test indicated an increase in corrosion resistance after using nanoparticles in all three acidic, neutral and alkaline environments. In addition, the potentiodynamic polarization test confirmed the mixed-protection mechanism in these three media. Furthermore, FE-SEM approach demonstrated the formation of a protective film on metal surfaces, and the EDS-Mapping evaluation confirmed these results in line with the element recognition.

Synthesis and evaluation of benzo[1,2,3]selenadiazole-isoxazoles as corrosion inhibitors for copper in NaCl: An integrated experimental and theoretical approach

In this study, we investigate the protective capabilities of two synthetic compounds, 5-methyl-5-(4-methylbenzo[d][1,2,3]selenadiazol-7-yl)-3-phenyl-4,5-dihydro-isoxazole (BHP) and 5-methyl-5-(4-methylbenzo[d][1,2,3]selenadiazol-7-yl)-3-(4-nitrophenyl)-4,5-dihydro-isoxazole (BNP), as corrosion inhibitors for copper in a 3.5 wt% NaCl solution. The chemical structure of these benzo[1,2,3]selenadiazolyl-isoxazole derivatives combines a benzo[1,2,3]selenadiazole core, which to our knowledge has not been previously studied for its anticorrosive activity on copper, with an isoxazole nucleus known in the literature as one of the most effective azoles in preventing copper corrosion. The efficiency and mechanism of copper corrosion inhibition were evaluated through electrochemical, theoretical, and morphological studies. Potentiodynamic polarization (PDP) showed that both BHP and BNP were effective in inhibiting copper corrosion. At 10−3 M, BHP showed a maximum inhibition efficiency of 80.24 %, while BNP achieved an even higher efficiency of 89.83 %. Adsorption behavior analysis indicated that both compounds followed the Langmuir isotherm. In addition, the high value of Kads (103 M−1) indicates a strong adsorption capacity of our molecules on the copper surface. The negative adsorption free energy (ΔG°ads=−34.14kJ/mol for BHP and ΔG°ads=−34.00kJ/mol for BNP) indicates a spontaneous adsorption process. Electrochemical impedance spectroscopy (EIS) showed that both compounds formed a thin protective layer on the copper surface, a finding further supported by surface morphology studies using scanning electron microscopy (SEM-EDX) and ATR-FTIR analysis.

Co(II) and Ni(II) complexes with bis(4-((E)-(4,5-diphenyl-1H-imidazol-2-yl)diazenyl) phenyl)methane: synthesis, characterization and anti-corrosion effect investigation

Bright coloured Co (II) and Ni (II) complexes of an azo ligand were synthesized. This ligand was previously synthesized from the coupling reaction between 4,5-diphenyl imidazole and 4,4-diaminodiphenylmethane in 1:2 molar ratio (4,4-diaminodiphenylmethane and 4,5-diphenyl imidazole). The synthesis process of the complexes involved the reflux reaction between the azo ligand with both metal salts. The synthesized complexes were characterized by FTIR, UV.-Visible, molar conductivity and atomic absorption. From the obtained characteristic data of the FTIR spectra, the coordination between the two metals and the azo ligand occurs by the coordination with the nitrogen atom of the azo group and one of the nitrogen atoms in the imidazole both rings. The molar conductivity test confirm the non- electrolytic nature of both complexes, while the atomic absorption agrees with the expected complexes formula. Therefore, the octahedral structure for the two complexes is suggested. The anti-corrosion activity of the synthesized compounds were investigated under two temperatures (298 and 308 K) with 0.03 gm of each compound was tested. According to the results cobalt (II) complex shows a better anti-corrosion activity (93%) in comparison with the ligand and nickel (II) complex. KEY WORDS: Cobalt(II) and nickel(II) azo complexes, Imidazole derivative, Anti-corrosion effect Bull. Chem. Soc. Ethiop. 2024, 38(4), 963-971. DOI: https://dx.doi.org/10.4314/bcse.v38i4.12

Justicia brandegeeana as a green corrosion inhibitor for carbon steel in sulfuric acid

ABSTRACT The anti-corrosive effect of the extract in ethanol of Justicia brandegeeana (Acanthaceae) against carbon steel AISI 1020 in sulfuric acid medium 1 mol L−1 was investigated. In addition to the effect of seasonality, several techniques were used to investigate the anti-corrosive activity, such as electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PP), linear polarization resistance (LPR), and weight loss. The chelating effect was analyzed by UV-Vis spectrophotometry and the surface was analyzed by scanning electron microscopy (SEM). The results showed that the inhibition efficiency is dependent on the concentration of the extract, reaching its maximum at 1500 ppm and despite having good thermal stability (82.41% inhibition at 70°C), it decreases with increasing temperature, indicating a physisorption behavior. The extract obeyed the Langmuir isotherm and the Tafel curves characterized it as a mixed inhibitor, with a tendency to cathodic region. It also presented a 52% chelating effect against Fe+2 ions, and the SEM analysis indicated a protection with the presence of plant extract, thus minimizing surface roughness. These results indicated the J. brangeeana ethanol extract as a green anti-corrosive agent.

RS-AAT with distributed permeable pipes and alkaline water: Enhancing concrete durability through chloride reduction, pH optimization, and pore structure improvement

Reverse-seepage and Saturation based Active Anti-corrosion Technology (RS-AAT) is a novel and environmentally-friendly approach that enhances the ability of unsaturated concrete in marine alternating wet-dry areas to resist chloride ion intrusion. Comprehending its influence on ions transport and the pore structure within the concrete is vital for assessing the rationality of the technique and further predicting its service life. In this study, cross-section specimens of cast in situ concrete piles with RS-AAT were exposed to a chloride wet-dry cycling environment for 150 days. Spatiotemporal variation patterns of chloride ion content, pore fluid pH, and pore structure in the concrete cover were investigated by free chloride titration, pH determination, and mercury intrusion porosimetry (MIP). The findings indicate that RS-AAT can effectively inhibit chloride ion intrusion into the protective layer of concrete. Moreover, implementing alkaline water in RS-AAT elevates the pore fluid pH and improves the compactness of the pore structure, especially diminishing the harmful pore ratio. Besides, increasing the number of distributed permeable pipes reinforces these effects and reduces the technology's dependence on water pressure. This insight demonstrates the viability of using alkaline water and distributed permeable pipes in RS-AAT to bolster the resistance of concrete structures to chloride ion erosion in an environmentally sustainable manner.

Anticorrosive action of eco-friendly plant extracts on mild steel in different concentrations of hydrochloric acid

Abstract The extracts of different parts of plants (leaf, stem, and flower) act as a green, environmentally friendly, economical, and safe corrosion inhibitors. The eco-friendly extracts of plant material provide an excellent alternative that substitutes toxic traditional (organic and inorganic) corrosion inhibitors. The plant extracts are renewable and readily available; thus, they occupy a unique position in the family of green inhibitors. The plant extract contains several bioactive compounds, such as flavonoids, tannins, polyphenols, phenolic acids, glycosides, flavonols, etc., which possess experienced significant interest as anti-corrosive agents. These plant extracts contain several heteroatoms like phosphorus, nitrogen, sulfur, oxygen, etc., which are adsorbed on the metallic surface and form an inert protective layer that protects metal from a corrosive environment. Thus, this article aims to shed light on the efficiency of plant extract in protecting steel in an acidic environment.

Synthesis of new azo compounds based on 4-aminosalicylic acid and study anti-corrosive activity

New azo dyes were prepared from 4-amino-2-hydroxy-benzoic acid in two steps; the first step includes preparation the diazonium salt. Then, diazonium compound coupled with different aromatic compounds containing donating groups (orcinol, 2,6-dimethylphenol, hydroquinone, catechol, 1,2,4-triazole, 2-methyl-naphthol and 4-toluidine, respectively). The physical properties of synthesized compounds were studied like melting point and solubility. The target molecules were characterized using FTIR, NMR and CHNS techniques. The activity of the compounds 1, 3 and 5 as anticorrosion on carbon steel in 0.5 M HCl solution was studied using weight loss method at different times and two concentrations (0.003 M, 0.005 M) of inhibitors at 298 K. Compound 5 showed more inhibition efficiency and less weight loss at different concentration in comparison with compound 1 and compound 3.&#x0D; KEY WORDS: Azo dye, 4-Aminosalicylic acid, Diazonium salt, Anti-corrosion&#x0D; Bull. Chem. Soc. Ethiop. 2024, 38(2), 473-479. &#x0D; DOI: https://dx.doi.org/10.4314/bcse.v38i2.14

Antioxidant and Anticorrosive Activities of the Plant Inula Viscosa L. from the Rif Region of Morocco

This work aims to highlight two activities of the abundant plant in the Rif region (northern Morocco), Inula viscosa L., namely, antioxidant and anticorrosive activity. We prepared extracts using the Soxhlet extraction technique using four solvents to increase polaritywich are water, and ethanol, ethyl acetate, and diethyl ethe. . Phytochemical screening is done using the Folin-ciocalteau method and the. AlCl3 The results of this work have shown that our extracts are rich in secondary metabolites such as flavonoids and flavonols, whose plant inspired its antioxidant capacity evaluated in vitro by the DPPH and FRAP techniques. The aqueous extract tested as a corrosion inhibitor showed considerable ability to inhibit the corrosion of mild steel in 1M HCl acidic media.