Inhibition of steel corrosion by unsaturated aldehydes in solutions of mineral acids

Effect of α,β-unsaturated aldehydes on the corrosion of mild steel in solutions of hydrochloric and sulfuric acids was investigated using gravimetric, voltammetric and chromato-mass spectrometry techniques. General regularities of corrosion and electrochemical behavior of these compounds in solutions of mineral acids are established. The role of the chemical transformation of α,β-unsaturated aldehydes in the inhibition of corrosion is shown.

► The protective effect of aldehydes increases with increasing unsaturation.
► Aldehydes with an unsaturated α,β-bond shielded by a bulky group are not inhibitors.
► Aldehydes in solutions of H2SO4 participate in the electrode reactions of steel.
► Cinnamic aldehyde can form protective film on the surface of the corroding steel.