2-Mercapto-1-methylimidazole as corrosion inhibitor for copper in hydrochloric acid (original) (raw)
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Inhibiting effects of 2-mercapto-1-methylimidazole on copper corrosion in 0.5 M sulfuric acid
Journal of Saudi Chemical Society, 2010
The inhibiting efficiency of 2-mercapto-1-methylimidazole (MMI) on copper corrosion in sulfuric acid was investigated at 30°C. Its effectiveness was assessed through electrochemical impedance spectroscopy, potentiodynamic polarization and gravimetric measurements. The results of study reveal that the inhibition efficiency of MMI depends on its concentration and attains approximately 81% at 10 À4 M. The inhibitor was adsorbed on the copper surface according the Langmuir adsorption isotherm model. The value of standard free energy of adsorption was calculated from this isotherm.
As copper protection is considered to be a very important task in acid media, where corrosion attacks are severe and costly. Surface sensitive techniques such as electrochemical quartz crystal microbalance (EQCM) and electrochemical scanning tunnelling microscopy (EC-STM) were applied to study the potential dependence of adsorption and kinetic properties of inhibitor film formation on copper surface in acidic environment. The investigated inhibitor was 5-mercapto-1-phenyl-tetrazole (5-MPhTT) and the electrolyte solution was 0.1M Na 2 SO 4 (pH=2.94). In order to study the electrode mass changes in the absence and presence of the inhibitor at rest potential, QCM investigations were performed. The apparent mass and current variation as a function of the electrode potential was registered in order to study the protective film and its breakdown. Surface morphology and anodic dissolution of Cu(111) electrodes in inhibited and uninhibited electrolytes were studied by in situ STM technique. Information about the nature of the protective layer was given by the STM images. The results were analyzed and discussed.
Journal of the Taiwan Institute of Chemical Engineers, 2019
Levamisole (LMS) and 4-phenylimidazole (PIZ), used as corrosion inhibitors of copper in sulfuric acid solution were explored by electrochemical tests, morphology analysis and theoretical calculation. At the concentration of 8 mM, the maximum corrosion inhibition efficiencies of LMS and PIZ are 99.03% and 95.84%, respectively. All test data found that LMS had better corrosion inhibition performance than PIZ. LMS is a cathodic corrosion inhibitor, while PIZ belongs to a mixed-type corrosion inhibitor. Electrochemical results indicate that the corrosion inhibition efficiency has the same trend when the concentration of corrosion inhibitor increases. Scanning electron microscope and atomic force microscope were applied to research the surface morphology of copper samples under different conditions. X-ray photoelectron spectroscopy and Langmuir adsorption isotherm model were utilized to explain adsorption means. What is more, Langmuir adsorption isotherm model indicates the coexistence of physisorption and chemisorption for the two inhibitors. Besides, the adsorption between LMS and copper is more prone to chemical adsorption. The mechanism of metallic copper and corrosion inhibitors was explored through quantum chemistry studies and molecular dynamics simulation.
2019
Inhibition performance of the heteroatoms organic compounds (HOC), namely Glutamic acid (GA), L-methionine (Meth), Cysteine (Cys) and phenyl mercapto tetrazol (PMT), as copper corrosion inhibitors for copper in 1M Acetic acid was investigated using Potentiodynamic polarization (PP) and electrochemical impedance spectroscopy (EIS) in the current study. The first comparative study distinguished GA and PMT as the best inhibitors from the HOC tested series. The detail study of PMT on the inhibition of the pure copper corrosion in 1M of Acetic Acid (AcA) solution showed that this compound exhibits a higher inhibition efficiency IE% at 5.10-4 M (89 %); moreover, IE% reaches 44 % at low concentration (10-5 M). The PP and EIS measurements indicate that the PMT molecules interacts with the copper surface forming a protective film in order to inhibit the corrosion by a physical chemical adsorption with respect to Langmuir adsorption isotherm model.
Inhibitive Action of Imidazoles for Copper Corrosion in Sulfuric Acid Medium
JOURNAL OF ADVANCES IN CHEMISTRY
The corrosion inhibition of copper in the presence of 10-3 M of imidazole derivatives; Imidazole (IM), 2-Methyle imidazole (MIM), Benzimidazole (BIM) has been investigated in 1.0 M H2SO4 solution using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Relationship between molecular structure and their inhibition efficiency was elucidated by quantum chemical calculations using the density functional theory (DFT) at the B3LYP/6-31+G(d,p) level. Inhibition efficiency of these compounds which has been evaluated via experimental methods was accorded with reported theoretical ones, and following the same order as BIM ˃ MIM ˃ IM.
Arabian Journal of Chemistry, 2011
The inhibiting action of 2-mercapto benzimidazole (2MBI) on mild steel in 1.0 M hydrochloric acid has been investigated at 308 K using weight loss measurements and electrochemical techniques (impedance spectroscopy and potentiodynamic polarisation). Inhibition efficiency increases with 2MBI concentration to attain 98% at 10 À3 M. Polarisation curves indicate that 2MBI acts as a mixed-type inhibitor. Inhibition efficiency values obtained from various methods were in good agreement. EIS measurements showed an increase of the transfer resistance with the inhibitor concentration. The temperature effect on the corrosion behaviour of steel in 1.0 M HCl without and with the 2MBI at various concentrations was studied in the temperature range from 308 to 353 K. Thermodynamic parameters such as heat of adsorption ðDH ads Þ, entropy of adsorption ðDS ads Þ and adsorption free energy ðDG ads Þ have been calculated. Kinetic parameters for the corrosion reaction at different concentrations of 2MBI were determined. Adsorption of 2MBI on the mild steel surface in 1.0 M HCl follows the Langmuir isotherm model.
Corrosion behavior of copper in 1.0 M Sulfuric acid containing either Imidazole (IM), 2-Methylimidazole (MIM) or Benzimidazole (BIM) was investigated experimentally via weight loss measurements and UV-Spectroscopy. The density functional theory (DFT) at the B3LYP/6-31G+ (2d, p) basis set level in gas phase is also applied here for theoretical study. Some quantum chemical parameters and the Mulliken charge densities on the optimized structures for imidazole compounds were determined. All theoretical results and experimental inhibition efficiencies of inhibitors were subjected to correlation analyses. Results obtained reveal that BIM is the best inhibitor and the inhibition efficiency (EW%) follows the sequence: BIM >MIM > IM. The adsorption behavior of BIM followed Langmuir's isotherm. Cu(I)−BIM complex formation was confirmed by UV spectroscopy.
Journal of Electrochemical Science and Technology
Two arylamino substituted mercaptoimidazole derivatives namely 4,5-dimethyl-1-(phenylamino)-1H-imidazole-2(3H)-thione (I1) and 4,5-dimethyl-1-((p-chlorophenyl)amino)-1H-imidazole-2(3H)-thione (I2) were synthesized and investigated as corrosion inhibitors for carbon steel in 0.5 M HCl solution by means of electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, ATR-FTIR spectroscopy and SEM. The results showed that the investigated mercaptoimidazole derivatives act as mixed type inhibitors and inhibition efficiency follows the I2>I1 order. Adsorption of inhibitors on metal surface was found to obey the Langmuir adsorption isotherm. Thermodynamic parameters revealed that adsorption of the inhibitors has both physisorption and chemisorption adsorption mechanism. Electrochemical test results were supported by quantum chemical parameters obtained from DFT calculations.
African Journal of Environmental Science and Technology, 2011
The inhibitive actions of 2-mercaptobenzimidazole (MBI) and 2-thiobenzylbenzimidazole (TBBI) on copper corrosion in 1M HNO 3 medium were studied, using weight loss method, at 25 to 65°C and concentrations of 5.10-5 M to 10-3 M. The results showed that the two compounds had fairly good inhibiting properties for copper corrosion in the medium, with efficiencies of 90.0% for TBBI and 87.7% for MBI at 25°C and concentration of 10-3 M. Modified Langmuir isotherm was found to provide an accurate description of the behavior of the two compounds. The thermodynamic functions of adsorption and the activation energy (E a) were calculated. Negative values of changes in free energies were obtained, indicating the spontaneity of the adsorption process. From thermodynamic adsorption and dissolution functions, both physisorption and chemisorption were proposed. Quantum chemical parameters such as highest occupied molecular orbital energy (E HOMO), lowest unoccupied molecular orbital energy (E LUMO), energy gap (ΔE) and dipole moment (µ) were calculated for these compounds, using DFT/B3LYP/6-31G (d,p) method in order to discuss the correlation between theoretical data and experimental results. It was found that theoretical data support the experimental results.