1,721,022 research outputs found
Inhibitive action of indole-5-carboxylic acid towards corrosion of mild steel in deaerated 0.5 M sulfuric acid solutions
No full textInhibition of mild steel corrosion in deaerated 0.5 M sulfuric acid solutions containing various concentrations of indole-5-carboxylic acid is studied in the temperature range from 25°C to 55°C using weight-loss, potentiodynamic and spectrophotometric tests. The adsorptive behaviour of inhibitor is also investigated using electrochemical impedance spectroscopy measurements. The indole-5-carboxylic acid is fond to shift the corrosion potentials towards more noble values. This shift indicates that the addition of inhibitor mainly affects the anodic process, raising the anodic overpotential more than that of the cathodic, i.e. the indole-5-carboxylic acid behaves as mixed-type inhibitor. Because the cathodic Tafel slopes for hydrogen reduction (bc) are affected, the inhibitor affects the hydrogen reduction mechanism. The activation energy value (Ea) obtained, indicates that the indole-5-carboxylic acid increases the activation energy of the corrosion reaction. The adsorption behaviour of indole-5-carboxylic acid follows Langmuir’s isotherm. Both the low values of - ΔG°ads and its decrease with temperature suggest physical adsorption.
Double layer capacitance-potential curves indicate considerable adsorption of the inhibitor in the potential range (-400 ÷ -800 mV/SCE)
Investigation of the inhibition effect of indole-3- carboxylic acid on the copper corrosion in 0.5 m H2SO4
No full textInhibition of the copper corrosion by means of indole-3-carboxylic acid (ICA), was studied in 0.5 M H2SO4 solutions in the temperature range from 25°C to 55 °C using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results obtained from the both measurement techniques revealed good inhibitor efficiency in the studied concentration range. Nyquist plots showed depressed semicircles with their centre below real axis. Moreover the impedance spectra in the case of both non inhibited solutions and inhibited ones by means of lower inhibitor concentrations exhibited Warburg impedance. The adsorption behaviour of ICA followed Langmuir’s isotherm
New magnetically recoverable palladium-based catalysts active in the alkoxycarbonylation of iodobenzene
No full textNew magnetically recoverable catalysts have been synthesized by deposition of 1 % palladium (Pd)-metal on the polymer poly(1-oxo-trimethylene), containing 15 % of magnetite. The magnetite allows the complete recovery of the catalyst with the simple application of an external magnetic field. The activity of such a catalyst has been studied under phosphine-free conditions in the alkoxycarbonylation of iodobenzene to the corresponding benzoic acid esters
The corrosion inhibition of the mild steel by indole-5-carboxylic acid in deaerated 0.5 M H2SO4
No full textDissociation of trifluoromethanesulfonic acid in aqueous solutions by Raman spectroscopy
No full text
- …
