Corrosion of 63/37 Brass in Citric Acid Solution and Its Inhibition by Azole Type Compounds

Chemistry Department, Bhavan's R. A. College of Science, Khanpur, Ahmedabad-380001 Manuscript received 13 February 1975, accepted 5 July 1977 The inhibitory action of imidazole, benzimidazole, 2-mercaptobenzimidazole and 2-mercaptobenzothiazole towards corrosion of brass in 0.1 M citric acid was investigated. The inhibitory power of these compounds was found in the following order: 2-mercaptobenzothiazole > 2-mercaptobenzimidazole > benzimidazole > imidazole Most of the compounds are able to form complexes with copper or/and zinc ions. The higher protection afforded by 2-mercaptobenzimidazole and 2-mercaptobenzothiazole may be due to formation of insoluble visible, adherent film on the copper surface. I.R. spectra of Cu-(MBT)2 complex has been taken for the explanation of chelate formation