Department of Chemistry, University of Calicut, Calicut University-673 635, Kerala, India E-mail ... more Department of Chemistry, University of Calicut, Calicut University-673 635, Kerala, India E-mail : [email protected] Department of Studies in Chemistry, Mangalore University, Mangalagangothri-574 199, Karnataka, India E-mail : [email protected] Manuscript received 7 August 2007, revised 29 October 2007, accepted 12 February 2008 The synthesis and characterization of complexes of Ag<sup>I</sup>, Tl<sup>I</sup>, Zn<sup>II</sup>, Cd<sup>II</sup> , Hg<sup>II</sup> , Co<sup>II</sup>, Ni<sup>II</sup> , Pd<sup>II</sup> , Ru<sup>II</sup>, Ru<sup>III</sup>, Rh<sup>III</sup> and Pt<sup>IV</sup> with 4-(pyridine-2-carboxylidineamino)-5-mercapto-1,2,4-triazole (<strong>PMT</strong>) have been carried out on the basis of chemical and physical methods like elemental analysis, infrared, <strong><sup>1</sup>H NMR</stron...
Effective inhibition of metallic corrosion to prevent its consequent loss is one of the serious a... more Effective inhibition of metallic corrosion to prevent its consequent loss is one of the serious apprehensions for industries in the modern world. This paper analyses the application of poly(2-ethyl-2-oxazoline) (PEOX) as an effective inhibitor of corrosion, when it is made to be in contact with the surfaces of mild steel (MS). The sustainability of MS against corrosion in 0.1 M Hydrochloric acid solution in the presence of known concentration of PEOX is assessed by potentiodynamic polarization (PDP) measurements, linear polarization studies (LPR), and electrochemical impedance spectroscopy (EIS). It was observed that PEOX behaves as better inhibitor for mild steel corrosion in 0.1 M HCl solution and it show enhanced inhibition efficiency (IE%) 79% at a concentration of 50 ppm. The polarization experiments indicated that addition of PEOX in concentrations varies from 25 ppm to 50 ppm induces a decrease of both cathodic and anodic currents densities. Also, the micrographs recorded by the Scanning Electron Microscopy confirm that molecules of PEOX act as corrosion inhibitors for the surfaces of MS in 0.1 M HCl. The stability of the MS surface in a corrosion-prone environment is traced by measuring the contact angles of water droplets placed on the MS surface, to quantify the extent of deterioration, if any, due to corrosion. The results presented here show that the compound PEOX performs as a mixed-type inhibitor against corrosion at the MS surface in acidic medium. Theoretical studies based on the electronic structure of PEOX in aqueous medium also support its performance as a successful corrosion-inhibitor.
Journal of Dispersion Science and Technology, 2012
The use of nitrogen and sulphur donor organic inhibitors in acid solutions is a common method for... more The use of nitrogen and sulphur donor organic inhibitors in acid solutions is a common method for the protection of metals from corrosion. The present work is the study of the corrosion inhibition efficiency of (E)-4-(2-chlorobenzylideneamino)-6methyl-3-thioxo-3,4-dihydro-1,2,4-triazin-5(2H)-one (CBMTDT) towards mild steel in 1 M HCl. The work strategy includes the conventional weight loss method, potentiodynamic polarization studies (Tafel), linear polarization studies (LPR), electrochemical impedance spectroscopy (EIS), adsorption studies and quantum chemical calculations. Results showed that the corrosion rate decreases and inhibition efficiency increases with inhibitor concentration. The results of polarization studies reveal that the additive acts as a mixed type inhibitor. The surface adsorption of the inhibitor molecules decreases the double layer capacitance and increases the polarization resistance. The adsorption process is spontaneous and follows Langmuir adsorption isotherm model. The optimized structure of the inhibitor, energies of LUMO, HOMO and other physical parameters are calculated by computational quantum chemical methods.
The inhibition effect of imidazolidine-2-thione (IMT) on the corrosion behaviour of mild steel (M... more The inhibition effect of imidazolidine-2-thione (IMT) on the corrosion behaviour of mild steel (MS) in 1 N HCl was studied using potentiodynamic polarization, linear polarisation resistance (LPR), electrochemical impedance spectroscopy (EIS) and adsorption studies. The effects of inhibitor concentrations, temperature, corrosion rate and surface coverage are investigated. The corrosion rate and other parameters are evaluated for different inhibitor concentrations and the probable mechanism is also proposed. The results show that IMT possesses excellent inhibiting effect for the corrosion of the MS and the inhibitor acts as a mixed type inhibitor. The inhibitor does not affects the mechanism of the electrode processes and inhibits corrosion by blocking the reaction sites. The high inhibition efficiency of IMT was due to the adsorption of inhibitor molecules on the metal surface. The decrease of surface area available for electrode reactions to take place is due to the formation of a protective film. Activation energies and enthalpies of activation in the presence and absence of IMT were determined by measuring the temperature dependence of the corrosion current.
The inhibition of copper corrosion in 1 M HNO 3 by (E)-(4-(4methoxybenzylideneamino)-4H-1, 2, 4-t... more The inhibition of copper corrosion in 1 M HNO 3 by (E)-(4-(4methoxybenzylideneamino)-4H-1, 2, 4-triazole-3, 5-diyl) dimethanol (MBATD) was investigated by polarization, ac impedance, adsorption studies, quantum chemical calculations, molecular dynamics methods and surface morphological studies. Polarization studies showed that MBATD acts as a mixed type inhibitor. Adsorption followed the Langmuir isotherm with negative value of free energy. Various thermodynamic and kinetic parameters were calculated to understand the energy changes associated during the inhibition process. The correlation between inhibitive effect and molecular structure is ascertained by quantum chemical calculations using density functional theory and Fukui functions. The molecular dynamics method has also been used to simulate the adsorption of inhibitor molecule on the metal surface.
Department of Chemistry, University of Calicut, Calicut University-673 635, Kerala, India E-mail ... more Department of Chemistry, University of Calicut, Calicut University-673 635, Kerala, India E-mail : [email protected] Department of Studies in Chemistry, Mangalore University, Mangalagangothri-574 199, Karnataka, India E-mail : [email protected] Manuscript received 7 August 2007, revised 29 October 2007, accepted 12 February 2008 The synthesis and characterization of complexes of Ag<sup>I</sup>, Tl<sup>I</sup>, Zn<sup>II</sup>, Cd<sup>II</sup> , Hg<sup>II</sup> , Co<sup>II</sup>, Ni<sup>II</sup> , Pd<sup>II</sup> , Ru<sup>II</sup>, Ru<sup>III</sup>, Rh<sup>III</sup> and Pt<sup>IV</sup> with 4-(pyridine-2-carboxylidineamino)-5-mercapto-1,2,4-triazole (<strong>PMT</strong>) have been carried out on the basis of chemical and physical methods like elemental analysis, infrared, <strong><sup>1</sup>H NMR</stron...
Effective inhibition of metallic corrosion to prevent its consequent loss is one of the serious a... more Effective inhibition of metallic corrosion to prevent its consequent loss is one of the serious apprehensions for industries in the modern world. This paper analyses the application of poly(2-ethyl-2-oxazoline) (PEOX) as an effective inhibitor of corrosion, when it is made to be in contact with the surfaces of mild steel (MS). The sustainability of MS against corrosion in 0.1 M Hydrochloric acid solution in the presence of known concentration of PEOX is assessed by potentiodynamic polarization (PDP) measurements, linear polarization studies (LPR), and electrochemical impedance spectroscopy (EIS). It was observed that PEOX behaves as better inhibitor for mild steel corrosion in 0.1 M HCl solution and it show enhanced inhibition efficiency (IE%) 79% at a concentration of 50 ppm. The polarization experiments indicated that addition of PEOX in concentrations varies from 25 ppm to 50 ppm induces a decrease of both cathodic and anodic currents densities. Also, the micrographs recorded by the Scanning Electron Microscopy confirm that molecules of PEOX act as corrosion inhibitors for the surfaces of MS in 0.1 M HCl. The stability of the MS surface in a corrosion-prone environment is traced by measuring the contact angles of water droplets placed on the MS surface, to quantify the extent of deterioration, if any, due to corrosion. The results presented here show that the compound PEOX performs as a mixed-type inhibitor against corrosion at the MS surface in acidic medium. Theoretical studies based on the electronic structure of PEOX in aqueous medium also support its performance as a successful corrosion-inhibitor.
Journal of Dispersion Science and Technology, 2012
The use of nitrogen and sulphur donor organic inhibitors in acid solutions is a common method for... more The use of nitrogen and sulphur donor organic inhibitors in acid solutions is a common method for the protection of metals from corrosion. The present work is the study of the corrosion inhibition efficiency of (E)-4-(2-chlorobenzylideneamino)-6methyl-3-thioxo-3,4-dihydro-1,2,4-triazin-5(2H)-one (CBMTDT) towards mild steel in 1 M HCl. The work strategy includes the conventional weight loss method, potentiodynamic polarization studies (Tafel), linear polarization studies (LPR), electrochemical impedance spectroscopy (EIS), adsorption studies and quantum chemical calculations. Results showed that the corrosion rate decreases and inhibition efficiency increases with inhibitor concentration. The results of polarization studies reveal that the additive acts as a mixed type inhibitor. The surface adsorption of the inhibitor molecules decreases the double layer capacitance and increases the polarization resistance. The adsorption process is spontaneous and follows Langmuir adsorption isotherm model. The optimized structure of the inhibitor, energies of LUMO, HOMO and other physical parameters are calculated by computational quantum chemical methods.
The inhibition effect of imidazolidine-2-thione (IMT) on the corrosion behaviour of mild steel (M... more The inhibition effect of imidazolidine-2-thione (IMT) on the corrosion behaviour of mild steel (MS) in 1 N HCl was studied using potentiodynamic polarization, linear polarisation resistance (LPR), electrochemical impedance spectroscopy (EIS) and adsorption studies. The effects of inhibitor concentrations, temperature, corrosion rate and surface coverage are investigated. The corrosion rate and other parameters are evaluated for different inhibitor concentrations and the probable mechanism is also proposed. The results show that IMT possesses excellent inhibiting effect for the corrosion of the MS and the inhibitor acts as a mixed type inhibitor. The inhibitor does not affects the mechanism of the electrode processes and inhibits corrosion by blocking the reaction sites. The high inhibition efficiency of IMT was due to the adsorption of inhibitor molecules on the metal surface. The decrease of surface area available for electrode reactions to take place is due to the formation of a protective film. Activation energies and enthalpies of activation in the presence and absence of IMT were determined by measuring the temperature dependence of the corrosion current.
The inhibition of copper corrosion in 1 M HNO 3 by (E)-(4-(4methoxybenzylideneamino)-4H-1, 2, 4-t... more The inhibition of copper corrosion in 1 M HNO 3 by (E)-(4-(4methoxybenzylideneamino)-4H-1, 2, 4-triazole-3, 5-diyl) dimethanol (MBATD) was investigated by polarization, ac impedance, adsorption studies, quantum chemical calculations, molecular dynamics methods and surface morphological studies. Polarization studies showed that MBATD acts as a mixed type inhibitor. Adsorption followed the Langmuir isotherm with negative value of free energy. Various thermodynamic and kinetic parameters were calculated to understand the energy changes associated during the inhibition process. The correlation between inhibitive effect and molecular structure is ascertained by quantum chemical calculations using density functional theory and Fukui functions. The molecular dynamics method has also been used to simulate the adsorption of inhibitor molecule on the metal surface.
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