Send Orders for Reprints to reprints@benthamscience.ae Electrochemical Analysis and Quantum Chemistry of Castor Oil-Based Corrosion Inhibitors (original) (raw)
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The corrosion inhibition of oleic, coconut, and stearic acid modified hydroxyethyl imidazolines on 1018 carbon steel was evaluated by using potenthiodynamic polarization curves, linear polarization resistance, and electrochemical impedance spectroscopy techniques. Solutions included deaerated CO 2 saturated 3% NaCl with and without Diesel at 50°C. Regardless of the presence of diesel, the corrosion rate was decreased with the addition of the inhibitors, but the time to reach a steady state was longer than when the oily part, i.e., diesel, was present. This was because the inhibitors are oil soluble, and with diesel, they are more easily transported towards the metal surface. With diesel, the formed film seems to be more stable and protective, not allowing the electrolyte to corrode the sample increasing the efficiency values up to 87 and 94%. The most efficient inhibitors were the coconut type fatty acid hidroxyethyl imidazoline because the formed film was much more stable from the beginning of the test, whereas the least efficient was the stearic acid modified hydroxyethyl imidazoline.
Journal of Solid State Electrochemistry, 2006
The corrosion behavior of hydroxyethyl, amino ethyl and amid ethyl imidazolines corrosion inhibitors was evaluated by using potenthiodynamic polarization curves, linear polarization resistance, and electrochemical impedance spectroscopy techniques. Solutions included deaerated 3% NaCl, 3% NaCl+diesel saturated with CO 2 at 50°C with and without inhibitors. Regardless of the presence of diesel, the corrosion rate was decreased with the addition of the inhibitors, but the time to reach a steady state was longer than when the oily part, i.e., diesel, was present. In the absence of the oily part, the impedance results showed that the film formed was porous, allowing the electrolyte to diffuse through it and corrode the metal. When the oily part was present, the film formed was much more stable, not porous, and did not allow the electrolyte to corrode the sample. The most efficient inhibitor was the amid ethyl imidazoline, whereas the least efficient was the hydroxyethyl imidazoline, because the film formed by the former was much more stable from the beginning of the test.
Imidazole derivative as effective oilfield corrosion inhibitor
Corrosion behavior of mild steel immersed in 0.5 M H2SO4 and corrosion inhibition in the presence of different concentrations of 2,4-di-tert-butyl-6-(1h-phenantro[9,10-d]imidazol-2-yl) phenol (PIP) was investigated using weight loss and hydrogen evolution techniques at 303 -333 K. The results indicate a maximum inhibition efficiency of 68.45% in the presence of 10 x 10-5 M PIP at 303 K. The inhibitory action of PIP in the acid solution is best described by Temkin adsorption isotherm. The Arrhenius and transition state equations are used to calculate activation parameters and the mechanism of physical adsorption is proposed for PIP from the values of Ea and ∆G*ads obtained. Thermodynamic studies indicate that the adsorption of PIP to the metal surface is spontaneous. Quantum chemical calculations using DFT is used to calculate some electronic properties of the molecule in order to ascertain any correlation between the inhibitive effect and molecular structure of the molecule PIP. PIP protected the mild steel against corrosion in the acid medium at the studied temperatures by virtue of adsorption. The corrosion rate increased with temperature both in the absence and presence of the inhibitor, but the increase was lesser in the presence of the inhibitor compared to that of the free acid solution. The inhibition efficiency increased with increase in concentration of the inhibitors.
Inhibition of mild steel corrosion in presence of fatty acid imidazolines in hydrochloric acid
Protection of Metals, 2008
The corrosive behavior of mild steel in 1M HCl solutions containing selected imidazolines of fatty acids with C7-C17 was investigated using weight-loss method, potentiodynamic polarization technique and scanning elecron microscopy. The results obtained revealed that all the studied imidazolines are effective in reducing corrosion of mild steel in HCl media. The adsorption of the inhibitors on the mild steel surface obeys Langmuir’s adsorption isotherm. The thermodynamic parameters of adsorption deduced reveal a strong interaction and spontaneous adsorption of inhibitors on the mild steel surface. The influence of inhibitor concentration, solution temperature, immersion time and acid concentration on the corrosion of mild steel has also been investigated. Scanning electron microscopy(SEM) of mild steels samples is performed to show adsorption of inhibitors on metal surface. Potentiodynamic polarization data showed that the compounds studied are mixed type inhibitors in the acid solution.
Corrosion Science, 2011
The corrosion inhibition performances of three corrosion inhibitors on mild steel in acidic medium, namely 1,3-thiazole (TA), 2-amine-1,3-thiazole (2-ATA), and 4-amine-1,3-thiazole (4-ATA), were theoretically evaluated using quantum chemistry calculations and molecular dynamics simulations both in gas phase and aqueous phase. The frontier orbital energy, global activity, and Fukui indices were studied. Adsorption energy of corrosion inhibitors on iron surface was calculated. Furthermore, a prediction of iron crystal morphology was performed, and the surface energies were obtained. The results indicate that Fe (1 1 0) surface possesses the lowest surface energy. 4-ATA shows the highest reaction activity among the three molecules. The binding energies of the corrosion inhibitor molecules and iron surface follow the order 4-ATA > 2-ATA > TA.
Materials and Corrosion, 2009
The effect of 2-(2-heptadec-8-enyl-4,5-dihydro-imidazol-1-yl)ethylamine on the corrosion behavior of mild steel in aqueous hydrochloric acid was investigated using weight loss measurements, polarization scans, electrochemical impedance, and X-ray photoelectron spectroscopy (XPS). The inhibition efficiencies and coverage degrees increased with the concentration of inhibitor but decreased proportionally with temperature. It appears that the steric hindrance of the aliphatic chain on the imidazoline ring adsorption may affect inhibitor efficiency. Polarization curves showed that the oleic imidazoline (OI) acted essentially as a mixed type inhibitor, in which the blocking of active sites occurred. As a result of film formation, impedance spectra revealed a considerable increase in the charge transfer resistance as indicated by the second capacitive loop. XPS depth profile analysis observed the presence of nitrogen and carbon species on the inhibitor film, which were associated to the OI.
Journal of Surfactants and Detergents, 2019
An optimized one-pot recipe has been developed to synthesize a surfactant molecule, referred to as OMID, consisting of an imidazoline head group and aliphatic tail, which is an exemplar corrosion inhibitor for carbon steel in acidic solutions. As evidenced by gas chromatography, 1 H and 13 C nuclear magnetic resonance, and Fourier-transform infrared data, a high-purity product was achieved without the use of either a solvent or catalyst. Critical micelle concentration values and corrosion inhibition efficiencies (η%) were determined in aqueous solutions of hydrochloric acid and sulfuric acid using surface tensiometry and linear polarization resistance measurements, respectively. Hydrolysis of the imidazoline head group as a function of pH (0-11) was explored with ultraviolet-visible absorption spectroscopy. In addition, N 1s and C 1s X-ray photoelectron spectroscopy data were acquired from both surface-adsorbed OMID and a multilayer of the imidazoline head group of OMID. These latter data are highly relevant to those attempting to understand OMID inhibition chemistry.
Imidazoline Derivatives Based on Coffee Oil as CO2 Corrosion Inhibitor
In this work, a hydroxyethyl-imidazoline derivate based on coffee oil has been synthesized and evaluated as an inhibitor of corrosion for carbon steel in CO 2 -saturated (3% NaCl + 10% diesel) emulsion at 50°C. Electrochemical impedance spectroscopy has been used to study the film formation on carbon steel. Performance of inhibitor was evaluated by adding 0, 5, 10, 25, 50, and 100 ppm. EIS data were used to calculate corrosion related electrochemical parameters, and this technique was shown to be a very useful tool for studying corrosion inhibitors. Optimal concentration is 10 ppm, by decreasing the corrosion rate by over 99.9%. Lower or higher concentrations increases the corrosion rate because the surface area covered by the inhibitor decreases, causing the formation of unprotected sites on the metal.
CO2 Corrosion Inhibition by Imidazoline Derivatives Based on Coconut Oil
A coconut-oil modified hydroxyetyl-imidazoline has been synthesized and used as an inhibitor of CO 2 corrosion for carbon steel in 3% NaCl solution at 50°C. Testing techniques includes potentiodynamic polarization curves, linear polarization resistance, electrochemical impedance spectroscopy, and electrochemical noise measurements by using 20 ppm of inhibitor. Results indicated that, even when the commercial imidazoline decreased the corrosion rate with efficiency higher than 400%, the coconut-oil modified imidazoline reduced the corrosion rate by more than 85%, giving promising results for using it as a green corrosion inhibitor.
Corrosion science, 2006
To proof the corrosion efficiency of hydroxyethyl, aminoethyl and amidoethyl imidazolines, they were evaluated by linear polarization resistance and polarization curves in deaerated 3% NaCl + Diesel + inhibitors saturated with CO 2 at 50°C. The most efficient inhibitor was the amido ethyl imidazoline, with an efficiency of 97.88% whereas the least efficient was the hydroxyethyl imidazoline, with an efficiency of 88.8%. A theoretical study of the corrosion inhibition efficiency of these imidazoline derivatives, was carried out using density functional theory (DFT). The computational calculations were used to obtain information about their molecular structure and those properties related with the inhibition efficiency of these inhibitors. The obtained correlations and theoretical conclusions agree well with the experimental results.