Inhibitive Effects of Propargyl Alcohol on Hydrogen Entry into Iron in Sulphuric Acid

Abstract

A novel method is proposed to examine and classify organic compounds added in an acid solution from the view of their behaviours against corrosion of metals and hydrogen entry. According to the method, a theoretical hydrogen content of iron is first calculated at a corrosion current density in an inhibited acid solution on the basis of the assumption that the inhibitor does not affect the mechanism of hydrogen evolution reaction on the iron surface except for reducing the effective surface area by its adsorption. The theoretical hydrogen content of iron is then compared with that determined by hydrogen Permeation current measurement. According to whether the measured hydrogen content of iron is greater or lower than the theoretical one, organic compounds are classified as either stimulator or inhibitor against hydrogen entry into iron during its corrosion in acid solutions. The method was applied to determine the role of propargyl alcohol against hydrogen entry into iron during its corrosion in deaerated 1N H₂SO₄ at 25°C. At all concentrations of ^-ropargyl alcohol tested, it was found that the measured hydrogen content of iron was lower than the theoretical one. Thus, propargyl alcohol is classified to be excellent inhibitor for hydrogen entry into iron as well as an effective corrosion inhibitor in the acid solution.