ESR spectra and kinetics of the disproportionation of substituted phenoxyl radicals. III. Cross-disproportionation in a system containing two phenols

Journal Article · Tue Sep 01 00:00:00 EDT 1987 · Kinet. Catal. (Engl. Transl.); (United States)

OSTI ID:5251432

Roginskii, V A; Krasheninnikova, G A

An ESR method was used to study the kinetics of radical reactions in systems of an initiator with two phenolic antioxidants. A theoretical analysis yielded formulas for calculating the equilibrium constant of reversible phenol-phenoxyl exchange reactions and the rate constant for the cross-disproportionation of phenoxyl radicals. Equilibrium and cross-disproportionation constants were measured for five different binary systems. From the results it was concluded that a connection exists between the cross-disproportionation rate constant and the structure of the phenol (in this case steric factors are most important than the O-H bond strength in the phenol). It is shown that the cross-disproportionation of phenoxyl radicals may lead to the generation of a more active antioxidant, as in the case of ionol + a synthetic analog of ..cap alpha..-tocopherol, leading to synergistic effects.

• Research Organization: Institute of Chemical Physics, Moscow (USSR)
• OSTI ID: 5251432
• Journal Information: Kinet. Catal. (Engl. Transl.); (United States), Vol. 28:2; Other Information: Translated from Kinet. Katal.; 28: No. 2, 305-312(Mar-Apr 1987)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
74 ATOMIC AND MOLECULAR PHYSICS
PHENOLS
ELECTRON SPIN RESONANCE
OXIDATION
REDUCTION
PHENOXY RADICALS
ACTIVATION ENERGY
ANTIOXIDANTS
CHEMICAL REACTION KINETICS
EFFICIENCY
EQUILIBRIUM
HYPERFINE STRUCTURE
MOLECULAR STRUCTURE
QUANTITY RATIO
STEREOCHEMISTRY
AROMATICS
CHEMICAL REACTIONS
ENERGY
HYDROXY COMPOUNDS
KINETICS
MAGNETIC RESONANCE
ORGANIC COMPOUNDS
RADICALS
REACTION KINETICS
RESONANCE
400201* - Chemical & Physicochemical Properties
640302 - Atomic
Molecular & Chemical Physics- Atomic & Molecular Properties & Theory