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Our objective is to compare the performance of the quantum parameters of two new synthesized multifunctional polymeric architectures: triglycidyl ether ethylene of bisphenol A (TGEEBA) and hexaglycidyl ethylene of methylene dianiline (HDEMDA). Calculations have been performed with Gaussian software package and the prediction of the quantum molecular descriptors of the two new macromolecular matrices are namely: the energy of the highest occupied molecular orbital (E HOMO), the energy of the lowest molecular orbital (E LUMO), the ionization potanial (IP), the electron affinity (EA), gap energy (ΔE), softness (σ), electronegativity (χ), hardness (ƞ), the electrophilic character (ω) and the function of the transferred electrons of coating on the surface of the metal (ΔN), etc. These were calculated by the functional density theory method (DFT) with 6–311 G (d, p) basis sets. The local reactivity of two polymers has been studied through the Fukui indices. Indeed, we conclude that the matrix HGEMDA has a low value of the adsorption energy than that of the TGEEBA, indicating that this polymer has a high adsorption capacity on the metal surface. Finally, the results obtained by the Monte Carlo simulation are in very good agreement with the data of the theory of the DFT. [ABSTRACT FROM AUTHOR]

Two benzonitrile derivatives, namely 4-(isopentylamino)-3-nitrobenzonitrile (PANB) and 3-amino-4-(isopentylamino)benzonitrile(APAB) have been synthesized and evaluated as corrosion inhibitors for mild steel (MS) in 1 M HCl solution at 303 K by gravimetric, potentiodynamic polarization (PDP) curves, and electrochemical impedance spectroscopy (EIS) methods, as well as Density Functional Theory (DFT) and molecular dynamics (MD) simulations. The results suggest that tested compounds are excellent corrosion inhibitors for mild steel with PANB showing superior performance. Polarization measurements revealed that PANB and APAB behaved as mixed type inhibitors. The polarization resistance, according to EIS studies, found to be dependent on the inhibitor's concentration. The adsorption of PANB and APAB on mild steel surface obeyed Langmuir's adsorption isotherm. On the one hand, DFT and MD simulations are being used to explain the effect of the molecular structure on the corrosion inhibition efficiency and on the other hand to simulate the adsorption of benzonitrile derivatives on mild steel surface. The protection of carbon steel in 1 M HCl was confirmed by using scanning electron microscope (SEM) and Atomic Force Microscopy (AFM). Electrochemical, DFT and MD simulations results are in good agreement. [ABSTRACT FROM AUTHOR]

• New methylquinoline-8-ol derivative was used is an effective corrosion inhibitor for carbon steel. • Anti-corrosion activity was performed using electrochemical techniques. • Surface analysis has been performed by SEM. • Experimental results have been combined by theoretical studies (DFT and MC). The present study provides a new application of the 5-(4-methylpiperazinyl)-methylquinolin-8-ol (MPMQ) as an inhibitor for corrosion of carbon steel (CS) in acidic media (1 M HCl). The inhibition performance of MPMQ was evaluated using various methods including electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), surface morphology analysis (SEM), quantum chemical computations (DFT), and Monte Carlo simulations (MC). The obtained results, indicating that the compound as a mixed-type inhibitor significantly reduced the corrosion rate of CS due to the formation of a stable protective film on the metal surface. As confirmed by EIS, SEM and theoretical studies, chemically adsorbed MPMQ molecule is a better corrosion inhibitor with higher corrosion performance of about 95% at room temperature. Langmuir isotherm model is the most acceptable one to describe the MPMQ molecules adsorption on the CS-surface. Finally, the experimental data correlated well with the theoretical study. [ABSTRACT FROM AUTHOR]

The adsorption and corrosion inhibition performance of two benzimidazole derivatives, namely:2-(allylthio)-1H-benzo[ d ]imidazole (SHA) and bis((1H-benzo[ d ]imidazole-2-yl)thio)methane (BB1C) were studied as a corrosion inhibitors for mild steel (MS) in 1.0 M HCl solution using Weight Loss (WL) measurements, Potentiodynamic Polarization (PDP), Electrochemical Impedance Spectroscopy (EIS), Scanning Electron Microscopy(SEM) and Energy Dispersive X-ray (EDX) analysis. The kinetics of corrosion retardation were inspected by polarization studies, and the respective achievements declared that both compounds could retard corrosion reactions via cathodic/anodic (mixed) inhibition mechanism. The adsorption process on MS surface obeyed Langmuir isotherm. Adsorption and thermodynamic parameters were also evaluated. SEM/EDX analysis strongly supports the obtained results and confirms the existence of a barrier film on the metal surface. Our findings provide deeper insights into understanding the interaction mechanisms of SHA and BB1C with MS surface. Experimental outcomes support the outcomes obtained from DFT and Molecular dynamic (MD) simulation. • Novel benzimidazole derivatives were synthesized as effective inhibitors for mild steel corrosion in HCl. • Polarization studies revealed the mixed type behavior for these molecules. • SEM and EDAX were performed for surface study. • Quantum chemical studies further support the experimental findings. [ABSTRACT FROM AUTHOR]

Two newly substituted methylquinolin-8-ol derivatives, namely 5-((aminooxy) methyl) quinolin-8-ol (AMQN) and 5-(hydrazinylmethyl) quinolin-8-ol (HMQN) was synthesized and characterized by 'IR' and NMR spectroscopy. The inhibition of AMQN and HMQN corrosion in 1 M HCl for carbon steel (CS) was performed by the coupling of electrochemical techniques like mass loss (MS), potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The experimental results show that the inhibition increases with the concentration and can reach a limit value of 97% for the inhibitor HMQN at 10−3 M. The polarization curves show that the 5-methylquinolin-8-ol derivatives (HMQN and AMQN) are of mixed type. The increase in temperature may have a decrease in the inhibition efficacy of the compounds studied. The adsorption of the two compounds (AMQN and HMQN) on the surface of the steel follows the Langmuir model. The study of the surface morphology is wearied out using scanning electron microscopy (SEM) coupled to EDX. This study is accomplished by in-depth theoretical calculations exploitation strategies supported density functional theory (DFT/B3LYP) and molecular dynamics (MD) simulations. • Novel 5-methylquinolin-8-ol derivatives were synthesized as an effective inhibitor for carbon steel corrosion in HCl. • Polarization studies revealed the mixed type behavior for these molecules. • The adsorption of both inhibitors obeys Langmuir adsorption isotherm and surface morphology was examined by SEM/EDAX. • Quantum chemical studies further support the experimental findings. [ABSTRACT FROM AUTHOR]

• Polarization studies revealed the mixed type behavior for these molecules. • The adsorption of both inhibitors obeys Langmuir adsorption isotherm and surface morphology was examined by SEM and UV-visible. • Quantum chemical studies further support the experimental findings. The inhibition efficiency (IE) of 4-hydroxy-8-isocyano-9-phenyl-3-(p -tolyl)-1,2-dihydropyrimido[2,1- c ][1,2,4]triazepine-5,7-dione (TRC-H) and 9-(4-chlorophenyl)-4-hydroxy-8-isocyano-3-(p -tolyl)-1,2-dihydropyrimido[2,1- c ][1,2,4]triazepine-5,7-dione (TRC-Cl) on the mild steel (MS) corrosion in 1 M HCl acid was studied by weight loss, electrochemical (EIS and PDP) techniques, DFT, molecular dynamic (MD) simulations, radial distribution function (RDF) and mean square displacement (MSD). TRC-H and TRC-Cl effect on the surface of MS has even been accentuated by scanning electron microscopy (SEM) and UV–visible. The adsorption on the steel is made according to the Langmuir model. Molecular dynamics simulation (MD) and Density Functional calculations were done to discussing their agreement with previously experimented results. [ABSTRACT FROM AUTHOR]

Material corrosion is one of the outstanding challenging problems in the industry, and it strongly influences refining and petrochemical plants lifetime. Therefore, prevention of the corrosion of different metals and alloys is imperative in the viewpoint of industrial safety and productivity. For this purpose, the application of suitable corrosion inhibitors is one of the most applicable solutions. The present paper focuses on the anticorrosive properties of three biologically active chalcones, namely (E)-2-(4-(3-(2,5 dimethoxyphenyl)acryloyl) phenoxy)acetic acid (AA-3), 2-(4-(3-(4-methoxyphenyl)propanoyl)phenoxy)acetic acid (AA-2) and (E)-2-(4-(3-(p-tolyl)acryloyl)phenoxy)acetic acid (AA-1) for mild steel in hydrochloric acid at temperature range 303−333 K. The corrosion inhibition performances of chalcones were evaluated by electrochemical tests, gravimetrical method, SEM, molecular orbital theory and molecular dynamics (MD) simulations. Results show that at the concentration of 5 × 10−3 molL-1, chalcone derivatives show high corrosion inhibition activities. All compounds are found to act via adsorption at the metal/solution interface, and their adsorption follows Langmuir isotherm model. Electrochemical tests indicate that the three chalcones act as mixed-type inhibitors. The thermodynamic data of adsorption were determined and discussed. Density Functional Theory (DFT) and MD simulations were used to assess the active sites of adsorption of the three inhibitors and their interaction with the iron surface, respectively. Scanning electron microscope (SEM) was used to analyze the surface morphological changes that chalcones induce in the corroded mild steel. The comparison of experimental results with theoretical data indicates that methoxy functional groups have a considerable influence on the anticorrosive properties of tested chalcones. [ABSTRACT FROM AUTHOR]