Abnormal Solvent Effects on Hydrogen Atom Abstractions. 1. The Reactions of Phenols with 2,2-Diphenyl-1-picrylhydrazyl (dpph•) in Alcohols

Rate constants, , for hydrogen atom abstraction from 13 hindered and nonhindered phenols by the diphenylpicrylhydrazyl radical, dpph •, have been determined in n-heptane and a number of alcoholic and nonalcoholic, hydrogen-bond accepting solvents. Abnormally enhanced values of have been observed in...

Full description

Saved in:
Bibliographic Details
Published inJournal of organic chemistry Vol. 68; no. 9; pp. 3433 - 3438
Main Authors Litwinienko, Grzegorz, Ingold, K. U.
Format Journal Article
LanguageEnglish
Published Washington, DC American Chemical Society 02.05.2003
Subjects
Chemistry
Exact sciences and technology
Kinetics and mechanisms
Organic chemistry
Reactivity and mechanisms
Solvent effect
DPPH
Organic free radical
Phenols
Alcohol
Kinetics
Rate constant
Online AccessGet full text

Cover

More Information
Summary:Rate constants, , for hydrogen atom abstraction from 13 hindered and nonhindered phenols by the diphenylpicrylhydrazyl radical, dpph •, have been determined in n-heptane and a number of alcoholic and nonalcoholic, hydrogen-bond accepting solvents. Abnormally enhanced values of have been observed in alcohols. It is proposed that this is due to partial ionization of the phenols and a very fast electron transfer from phenoxide anion to dpph •. The popular assessment of the antioxidant activities of phenols with dpph • in alcohol solvents will generally lead to an overestimation of their activities.
Bibliography:istex:CB88C385B0525C77E666B7633D37477CF026AF81
ark:/67375/TPS-SF2W0894-G
ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:0022-3263
1520-6904
DOI:10.1021/jo026917t