2, 4‐Dinitrophenylhydrazine as a Corrosion Inhibitor for Copper in Sulphuric Acid

Abstract

Corrosion rates of copper in 1N sulphuric acid with various concentrations (10−8 to 10−4 M) of 2, 4‐dinitrophenylhydrazine (2, 4‐DNP) are determined by weight loss method. The corrosion rates (under diffusion control), are a function of the stirring rate and the concentration of 2, 4‐DNP. The corrosion rate decreased markedly on increasing the concentration of 2, 4‐DNP. The maximum corrosion inhibition (85%) is observed at 10−4 M 2, 4‐DNP. The anodic polarization data and the drift in corrosion potential with time towards the less noble direction reveal the inhibition of cathodic reaction of the corrosion process by 2, 4‐DNP. A mechanism is proposed to explain the inhibitor action of 2, 4‐DNP on copper during corrosion in 1N sulphuric acid.