Reaction of carbon with oxidizing gases: The role of unpaired electrons

✍ Scribed by H. Harker; J.T. Gallagher; A. Parkin

• Book ID: 102992034
• Publisher: Elsevier Science
• Year: 1966
• Tongue: English
• Weight: 723 KB
• Volume: 4
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(66)90053-4

✦ Synopsis

A study has been made of the reaction of oxygen with cellulose carbons prepared over a range of temperature. The free radical centres, detectable by ESR, are not outstandingly reactive to oxygen. Carbon dioxide, carbon monoxide and surface-oxide appear to arise at separate sites and some suggestions are made regarding the mechanisms involved.

Nitric oxide reacts with carbon at temperatures as low as-78°C. Sites of high reactivitv must therefore be present, but it is unlikely that they represent spin centres, because the rates of reaction measured at 0°C did not correlate with unpaired electron concentrations.

Exposure of the carbon to nitric oxide at this temperature resulted in a non-reversible decay of ESR signal, which is believed to be due to the formation of a weakly-held surface-complex.

The low reactivity of the free-radical centres is probably a consequence of the x-character of the unpaired electrons, which would allow stabilization by resonance over several carbon atoms.