Corrosion inhibition properties of pyrazolylindolenine compounds on copper surface in acidic media
1 Department of Chemistry, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
2 Department of Chemistry, Faculty of Science, Islamic Azad University- Gorgan Branch, Gorgan, Iran
3 Nanotechnology & catalysis research centre, Institute of postgraduate studies, University of Malaya, 50603, Kuala Lumpur, Malaysia
Chemistry Central Journal 2012, 6:163 doi:10.1186/1752-153X-6-163Published: 31 December 2012
The corrosion inhibition performance of pyrazolylindolenine compounds, namely 4-(3,3-dimethyl-3H-indol-2-yl)-pyrazole-1-carbothioamide (InPzTAm), 4-(3,3-dimethyl-3H-indol-2-yl)-1H-pyrazole-1-carbothiohydrazide (InPzTH) and 3,3-dimethyl-2-(1-phenyl-1H-pyrazol-4-yl)-3H-indole (InPzPh),) on copper in 1M HCl solution is investigated by electrochemical impedance spectroscopy (EIS), open circuit potential (OCP) and linear scan voltammetry (LSV) techniques.
The results show that the corrosion rate of copper is diminished by the compounds with the inhibition strength in the order of: InPzTAm> InPzTH > InPzPh. The corrosion inhibition efficiencies for the three inhibitors are 94.0, 91.4 and 79.3, for InPzTAm, InPzTH and InPzPh respectively with the same inhibitor concentration (2 mM).
From the EIS, OCP and LSV results it was concluded that pyrazolylindolenine compounds with S-atom (with an amine group) have illustrated better corrosion inhibition performance compared to hydrazine and phenyl group.