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Pyrazole Derivatives as Corrosion Inhibitors for Steel in Hydrochloric Acid
Herrag,L.; Chetouani,A.; Elkadiri,S.; Hammouti,B.; Aouniti,A.;
Portugaliae Electrochimica Acta , 2008,
Abstract: the effect of 1-{[benzyl-(2-cyano-ethyl)-amino]-methyl}-5-methyl-1h-pyrazole-3-carboxylic acid methyl ester (p1) and 1-{[benzyl-(2-cyano-ethyl)-amino]-methyl}-5-methyl-1h-pyrazole-3-carboxylic acid ethyl ester (p2) was evaluated as corrosion inhibitors of steel in molar hydrochloric using weight loss measurements and electrochemical polarisation. the results obtained reveal that those compounds reduce the corrosion rate. the inhibiting action increases with the concentration of pyrazole compounds to attain 98.5 % at the 10-3 m of (p2). the increase in temperature leads to a decrease in the inhibition efficiency of the compounds in the temperature range 308 - 353 k. the adsorption isotherm of inhibitors on the steel has been determined. the thermodynamic data of activation and adsorption are determined.
Pyrazole Derivatives as Corrosion Inhibitors for Steel in Hydrochloric Acid  [cached]
L. Herrag,A. Chetouani,S. Elkadiri,B. Hammouti
Portugaliae Electrochimica Acta , 2008,
Abstract: The effect of 1-{[benzyl-(2-cyano-ethyl)-amino]-methyl}-5-methyl-1H-pyrazole-3-carboxylic acid methyl ester (P1) and 1-{[benzyl-(2-cyano-ethyl)-amino]-methyl}-5-methyl-1H-pyrazole-3-carboxylic acid ethyl ester (P2) was evaluated as corrosion inhibitors of steel in molar hydrochloric using weight loss measurements and electrochemical polarisation. The results obtained reveal that those compounds reduce the corrosion rate. The inhibiting action increases with the concentration of pyrazole compounds to attain 98.5 % at the 10-3 M of (P2). The increase in temperature leads to a decrease in the inhibition efficiency of the compounds in the temperature range 308 - 353 K. The adsorption isotherm of inhibitors on the steel has been determined. The thermodynamic data of activation and adsorption are determined.
Use of Hydrazone Derivates as Inhibitors for the Corrosion of Nickel in Hydrochloric Acid Solution
A.S. Fouda, H. A. Mostafa, S. E. Ghazy and S. A. El- Farah
International Journal of Electrochemical Science , 2007,
Abstract: The influence of hydrazone derivatives on the corrosion of nickel in 2 mol L-1 hydrochloric acid solution has been studied using weight loss and galvanostatic polarization techniques. In general, at constant acid concentration, the inhibition efficiency increases with increasing the inhibitor concentration and decreases with increasing temperature. Polarization studies indicate that the compounds act as mixed- type inhibitors. The addition of iodide ions enhances the inhibition efficiency to a considerable extent .The effect of temperature on corrosion inhibition has been studied and activation energy has been calculated. Some thermodynamic parameters are calculated and discussed.
Schiff Bases of Triethylenetetramine as Corrosion Inhibitors of Zinc in Hydrochloric Acid
Shah,M.D.; Patel,A.S.; Mudaliar,G.V.; Shah,N.K.;
Portugaliae Electrochimica Acta , 2011,
Abstract: the performance of triethylenetetramine-tribenzylidene (tttb) and triethylenetetramine-trisalicylidene (ttts) as corrosion inhibitors for zinc in hydrochloric acid is investigated. at lower concentrations, both inhibitors accelerate the attack but inhibit corrosion at higher concentrations, e.g., 96-100% with 1.0% concentration in 0.5 m and 1.0 m hcl. the efficiency of tttb decreases while that of ttts remains almost constant (≥ 99.7%) up to 120 minutes and in the temperature range 35 - 65 oc. the activation energies are higher in inhibited than in plain acid with both inhibitors. the free energy of adsorption (δgads) and heat of adsorption (qads) are negative, which suggests that there is spontaneous adsorption on metal surface, and from the values of (δgads) and (qads), the values of entropy of adsorption (δsads) were calculated. galvanostatic polarization shows that corrosion is under mixed control with predominance of the cathodic part. in uninhibited 1.0 m hcl, complete cathodic protection is achieved at a current density of 4.2224 adm-2, but in presence of these inhibitors, much lower current densities are required. plot of log (θ/1-θ) versus log cinh gives a straight line, suggesting that inhibitors cover both the anodic and cathodic regions through general adsorption following langmuir isotherm. the mechanism of inhibition has been proposed.
Schiff Bases of Triethylenetetramine as Corrosion Inhibitors of Zinc in Hydrochloric Acid  [cached]
M.D. Shah,A.S. Patel,G.V. Mudaliar,N.K. Shah
Portugaliae Electrochimica Acta , 2011,
Abstract: The performance of triethylenetetramine-tribenzylidene (TTTB) and triethylenetetramine-trisalicylidene (TTTS) as corrosion inhibitors for zinc in hydrochloric acid is investigated. At lower concentrations, both inhibitors accelerate the attack but inhibit corrosion at higher concentrations, e.g., 96-100% with 1.0% concentration in 0.5 M and 1.0 M HCl. The efficiency of TTTB decreases while that of TTTS remains almost constant (≥ 99.7%) up to 120 minutes and in the temperature range 35 - 65 oC. The activation energies are higher in inhibited than in plain acid with both inhibitors. The free energy of adsorption (ΔGads) and heat of adsorption (Qads) are negative, which suggests that there is spontaneous adsorption on metal surface, and from the values of (ΔGads) and (Qads), the values of entropy of adsorption (ΔSads) were calculated. Galvanostatic polarization shows that corrosion is under mixed control with predominance of the cathodic part. In uninhibited 1.0 M HCl, complete cathodic protection is achieved at a current density of 4.2224 Adm-2, but in presence of these inhibitors, much lower current densities are required. Plot of log (θ/1-θ) versus log Cinh gives a straight line, suggesting that inhibitors cover both the anodic and cathodic regions through general adsorption following Langmuir isotherm. The mechanism of inhibition has been proposed.
4-Chloro-N′-(4-methoxybenzylidene)benzohydrazide methanol monosolvate
Hai-Tao Huang,Hong-Yuan Wu
Acta Crystallographica Section E , 2010, DOI: 10.1107/s1600536810038857
Abstract: The title compound, C15H13ClN2O2·CH4O, consists of a 4-chloro-N′-(4-methoxybenzylidene)benzohydrazide (CMB) molecule and a methanol molecule of crystallization. It was obtained by the condensation of 4-methoxybenzaldehyde with 4-chlorobenzohydrazide. In the CMB molecule, the dihedral angle between the two benzene rings is 50.1 (3)°. The methanol molecule is linked to the CMB molecule through O—H...O and O—H...N hydrogen bonds. In the crystal, CMB molecules are linked through intermolecular N—H...O hydrogen bonds, involving the methanol molecule, forming chains propagating along [010].
QSPR prediction analysis of corrosion inhibitors in hydrochloric acid on 22%-Cr stainless steel
Cardoso, S. P.;Hollauer, E.;Borges, L. E. P.;Gomes, J. A. da C. P.;
Journal of the Brazilian Chemical Society , 2006, DOI: 10.1590/S0103-50532006000700008
Abstract: corrosion inhibitors have been widely used to prevent corrosion on stimulation operations on petroleum wells. detailed experimental and theoretical investigation of twenty three different compounds including amines, thiourea derivatives, and acetylenic alcohols were carried out to estimate their inhibition corrosion efficiency on 22% cr stainless steel (austenitic-ferritic, duplex) in hydrochloric acid (15% m/v) solutions. the obtained data were theoretically interpreted with respect to prediction, regression analysis (ols), principal analysis component (pca) and partial regression analysis (pls) employing quantum and group contribution descriptors. in our study we found advantage in the use of the weight isoesteric langmuir adsorption function (wila), ln(qm/(1-q)) or lnkads. excellent correlations were obtained for most models and few equations, results, calibration and validation plots were discussed in the text. the content of the present work represents a first step toward an efficient estimation of the inhibition corrosion efficiency (ice) of arbitrary inhibitors towards several metals, alloys and steel types.
Triazole derivatives as corrosion inhibitors for mild steel in hydrochloric acid solution

Fengling XU,Baorong HOU,

金属学报(英文版) , 2009,
Abstract: The title compounds 1-(4,5-dihydro-3-phenyl pyridine-1-yl)-2-(1H-1,2,4-triazole-1-yl)ethyl ketones were studied as a corrosion inhibitor in a mild steel in 1 mol /L hy-drochloric acid solution using weight loss measurement,potentiodynamic polariza-tion,and electrochemical impedance spectroscopy(EIS).Results indicated that these compounds had excellent inhibition properties.Polarization curves indicated that the inhibitor behaved mainly as mixed-type inhibitor.The EIS results showed that the charge transfer ...
Chemical Polymerization of Aniline in Hydrochloric Acid (HCl) and Formic Acid (HCOOH) Media. Differences Between the Two Synthesized Polyanilines
American Journal of Polymer Science , 2012, DOI: 10.5923/j.ajps.20120202.02
Abstract: Conductive polyaniline (doped PAni) was synthesized by a chemical method in media containing, respectively, hydrochloric (HCl) and formic acid (HCOOH). The FT-IR and Raman results showed that the doping degree of PAni-HCOOH is greater than that of the PAni-HCl. Additionally, the Raman studies indicated that the oxidation degree of PAni-HCOOH is higher than that of PAni-HCl, and that polaron segments dominate the PAni-HCOOH structure. The thermogravimetric analysis (TGA) in oxidizing atmosphere also suggests that the doping level of PAni with HCOOH is higher than that of PAni with HCl. The DSC results confirm the differences of the thermal degradation mechanism, in non oxidative atmosphere, of the polymeric chain of both polyanilines. The electrical conductivity of the PAni-HCOOH was 7.51 S cm-1, while that of the PAni-HCl was 0.143 S cm-1 confirming the results of FT-IR, Raman and TGA, i.e., the oxidation and the doping degree of PAni-HCOOH is higher than that of PAni-HCl.
3-Chloro-4-fluoro-N-{[3-(4-methoxyphenyl)-1-phenyl-1H-pyrazol- 4-yl]methyl}aniline  [PDF]
Sandhya Bawa,Fasih Ahmad,Suresh Kumar
Molbank , 2009, DOI: 10.3390/m640
Abstract: A direct reductive amination of 3-(4-methoxyphenyl)-1-phenyl-1H-pyrazole-4-carbaldehyde 2 with 3-chloro-4-flouroaniline using NaBH4/I2 as a reducing agent is described. The reaction was carried out in MeOH under neutral conditions at room temperature to give the secondary amine, 3-chloro-4-fluoro-N-{[3-(4-methoxyphenyl)-1-phenyl-1H-pyrazol-4-yl]methyl}aniline (3).
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