Why are amine quinones monomers used for corrosion inhibition

CHED 700

Michael J. Campbell, Caleb M. Hill, and Andrew B. Helms, ahelms@jsu.edu. Department of Physical and Earth Sciences, Jacksonville State University, 700 Pelham Road, Jacksonville, AL 36265
Amine quinones have been used in polymers to inhibit corrosion on a variety of metal substrates. This study investigates the mechanism of that corrosion inhibition. The addition of the amine groups to the p-benzoquinone provides a resonance structure that has an electron rich carbonyl group. The evidence for this is shown in the 100 cm-1 shift down in the infrared spectrum for the carbonyl between p-benzoquinone and amine quinone monomers. The electron density is being donated into the anti-bonding orbitals which cause the negative shift in the infrared spectrum. With the additional electron density available, the binding energy for the valence electrons of oxygen is decreased and that excess electron density can be donated into the surface and decrease the overall rate of corrosion.