The effects of complexing agents on the corrosion of iron in an anhydrous methanol solution

Abstract

Polarization curves of an iron electrode in an anhydrous methanol solution of 0.1 M LiClO 4 containing various basic and acidic complexing agents (water content < 150 ppm) were discussed with respect to the proton concentration in methanol, the stability constant of the ferrous complex and X-ray photo-electron spectra of the electrode surface treated with the complexing agents. Because most of the cathodic polarization curves were independent of the proton concentration in the methanol solution, a cathodic reaction of methanol being directly reduced to form a hydrogen molecule and methoxide ion was proposed. The anodic process was stimulated with the complexing agent by the formation of a soluble complex in the solution. The stimulation of the anodic process is closely associated with the stability constant of the complex. Both cathodic and anodic processes were suppressed when a layer of the complex deposit formed on the surface.