Imidazolidine-2-thion-4-on and its derivatives stimulate efficiently the acid corrosion of iron. Examination by x-ray photoelectron spectroscopy and microscopy in secondary electrons showed that the molecules of imidazolidine are present on the surface and are subjected to oxidation breakdown in the ethanol medium with the formation of a sulfate. In subsequent cathodic polarization in 2N H2SO4 with the addition of the same imidazolidine or a derivative the residues of the dissociated molecules are displaced by nondistorted molecules in which one of the groups -NH- is completely protonized. The adsorption bond through the sulfur atoms was not unambiguously confirmed by photoelectron spectra, although the participants of the thion group in this bond is indicated by the easy oxidizability of the molecules and the catalytic effect of the surface.
Nature of the surface film formed by imidazolidine-2-thion and its derivatives on ARMCO iron.
ISAIA, FRANCESCO;ROSSI, ANTONELLA;
1989-01-01
Abstract
Imidazolidine-2-thion-4-on and its derivatives stimulate efficiently the acid corrosion of iron. Examination by x-ray photoelectron spectroscopy and microscopy in secondary electrons showed that the molecules of imidazolidine are present on the surface and are subjected to oxidation breakdown in the ethanol medium with the formation of a sulfate. In subsequent cathodic polarization in 2N H2SO4 with the addition of the same imidazolidine or a derivative the residues of the dissociated molecules are displaced by nondistorted molecules in which one of the groups -NH- is completely protonized. The adsorption bond through the sulfur atoms was not unambiguously confirmed by photoelectron spectra, although the participants of the thion group in this bond is indicated by the easy oxidizability of the molecules and the catalytic effect of the surface.
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