Effect of substituents on corrosion inhibition efficiency of arylisothiocyanates and their condensation products with thiosemicarbazide for corrosion of copper in aqueous chloride solution

Abstract

The inhibition of copper corrosion in 1.5% sodium chloride solution was studied at 25, 35 and 45°C using different concentrations of thiosemicarbazide, p-methoxyphenyl isothiocyanate, p-methylphenyl isothiocyanate and p-chlorophenyl isothiocyanate and their corresponding condensation products with thiosemicarbazide. The inhibition efficiency IE of these compounds was evaluated by weight loss and electrochemical polarisation techniques. Substitution at p-position in the phenyl group resulted in change in IE in the following order for both the aryl isothiocyanates and their corresponding condensation products with thiosemicarbazide-pchlorophenyl-< phenyl- < p-methylphenyl- < p-methoxyphenyl.