Synergistic effect p-phenylenediamine and n,n diphenylthiourea on the electrochemical corrosion behaviour of mild steel in dilute acid media

Electrochemical studies of the synergistic effect of p-phenylenediamine and n,n diphenylthiourea (TPD) as corrosion inhibitor of mild steel in dilute sulphuric and hydrochloric acid through weight loss and potentiodynamic polarization at ambient temperature were performed. Experimental results showed the excellent performance of TPD with an optimal inhibition efficiency of 88.18 and 93.88 %in sulphuric and 87.42 and 87.15 %in hydrochloric acid from both tests at all concentration studied. Polarization studies show the compound to be a mixed-type inhibitor. Adsorption of deanol on the steel surface was observed to obey the Langmuir and Frumkin isotherm models. X-ray diffractometry confirmed the absence of corrosion products and complexes. Optical microscopy confirmed the selective inhibition property of TPD to be through chemical adsorption on the steel surfac

Corrosion inhibition properties of pyrazolylindolenine compounds on copper surface in acidic media

<p>Abstract</p> <p>Background</p> <p>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.</p> <p>Results</p> <p>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).</p> <p>Conclusion</p> <p>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.</p

Convolvulus

Convolvulus genus is a representative of the family of Convolvulaceae. Convolvulus plants are broadly distributed all over the world and has been used for many centuries as herbal medicine. Convolvulus genus contains various phytochemicals such as flavonoids, alkaloids, carbohydrates, phenolic compounds, mucilage, unsaturated sterols or terpenes, resin, tannins, lactones, and proteins. This review highlights the phytochemical composition, antimicrobial and antioxidant activities, application as food preservative, traditional medicine use, anticancer activities, and clinical effectiveness in human of Convolvulus plants. All the parts of Convolvulus plants possess therapeutic benefits; preliminary pharmacological data validated their use in traditional medicine. However, further preclinical and clinical experiments are warranted before any application in human health