Electrochemical and Corrosion Behavior of Iron in Presence of Substituted Benzotriazoles

The effect of benzotriazole (BTA), 5-methyl, 5-carboxy, 5-amino, 5-chloro, and a mixture of 5-carboxy and 4-carboxy benzotriazoles on iron corrosion and hydrogen evolution in H₂SO₄ was examined. At the concentrations of maximum inh bition, corrosion inhibition increased in the following order: NO₂ - < Cl - < mixed COOH - < COOH - < BTA ≈ CH₃ - < NH₂ - . The results indicate that the COOH-BTA, and the mixed COOH-BTA were the most effective inhibitors on the basis of the quantity of organic required for maximum inhibition. An apparent linear free energy relationship was obtained for the corrosion rate at the concentrations of maximum inhibition.