Magnetic field effect on the oxidation of organic substances by molecular oxygen

• Published in: Journal of physical organic chemistry Vol. 32; no. 4
• Main Authors: Pliss, Evgeny M., Grobov, Aleksey M., Kuzaev, Anton K., Buchachenko, Anatoly L.
• Format: Journal Article
• Language: English
• Published: Bognor Regis Wiley Subscription Services, Inc 01-04-2019
• Subjects: Chains; Liquid phases; Magnetic effects; magnetic field effect; Magnetic fields; Organic compounds; Oxidation; Oxygen
• ISSN: 0894-3230; 1099-1395
• DOI: 10.1002/poc.3915

Magnetic field effect (ME) on certain steps of chain oxidation of organic compounds of different series by molecular oxygen in liquid phase (initiation, chain propagation, and termination) is presented as a function of [O2] in two regimes. At low concentration of oxygen (<1.5 mM), magnetic field accelerates oxidation by 10% to 100%, but at high concentration no magnetic effect is detected. The dominating contribution into the magnetic effect (ME) is provided by reaction of alkyl radicals to oxygen: R• + O2 → RO2•. This reaction is stimulated by the Zeeman interaction which transforms in the encounter pair (R• O2) producing transformation of quartet spin state, which is spin forbidden to react, into the doublet spin state, which is spin allowed. At high concentration of oxygen, this reaction is not a limiting step and provides no magnetic effect on the total rate of oxidation.
The dominating contribution into the magnetic effect (ME) is provided by reaction of alkyl radicals to oxygen: R• + O2 ‐> RO2•. This reaction is stimulated by the Zeeman interaction that transforms in the encounter pair (R• O2) producing transformation of quartet spin state, which is spin forbidden to react, into the doublet spin state, which is spin allowed. At high concentration of oxygen, this reaction is not a limiting step and provides no magnetic effect on the total rate of oxidation.