The inhibition of mild steel corrosion in hydrochloric acid by 2,2′-pyridil and α-pyridoin

Abstract

The effect of closely related α-pyridoin and 2,2′-pyridil on the corrosion behaviour of mild steel in hydrochloric acid solution has been studied. Weight loss and hydrogen evolution measurements reveal that α-pyridoin gives a better inhibition effect than 2,2′-pyridil. The inhibition effect is more pronounced with increasing temperature as well as inhibitor concentration. Chemical adsorption mechanism has been proposed for the two inhibitors. α-Pyridoin and 2,2′-pyridil obey the Freundlich adsorption isotherm equation at all concentrations and temperatures. The higher efficiencies of the α-pyridoin have been explained in terms of high solubility of the compound facilitated by hydrogen bonding with solvent molecules. α-Pyridoin is also considered to form a more stable bond with mild steel.