Origin of free radicals produced from the syringyl end groups in lignins

Enzyme lignin was prepared from reed; it was acid-hydrolyzed and reduced with NaBH4. Spin concentrations of radicals produced by oxidation of the lignins with K3[Fe(CN)6] or H2O2 were determined from electron spin resonance spectra. The radicals were observed by the oxidation of sinapyl alcohol. It...

Full description

Saved in:
Bibliographic Details
Published inJournal of wood science Vol. 44; no. 4; pp. 314 - 319
Main Author Oniki, T. (Kyushu Dental Univ., Kitakyushu, Fukuoka (Japan))
Format Journal Article
LanguageEnglish
Published Heidelberg Springer Nature B.V 01.08.1998
Subjects
Carbonyl groups
Carbonyls
Electron paramagnetic resonance
Electron spin
ESPECTROSCOPIA ESR
ESR SPECTROSCOPY
Free radicals
Hydrogen peroxide
Hydroxyl groups
LIGNINAS
LIGNINE
LIGNINS
Oxidation
PHRAGMITES
Potassium ferricyanide
REDUCCION
REDUCTION
SPECTROSCOPIE RSE
Spin resonance
Stilbene
Online AccessGet full text

Cover

More Information
Summary:Enzyme lignin was prepared from reed; it was acid-hydrolyzed and reduced with NaBH4. Spin concentrations of radicals produced by oxidation of the lignins with K3[Fe(CN)6] or H2O2 were determined from electron spin resonance spectra. The radicals were observed by the oxidation of sinapyl alcohol. It was found that the two radicals observed by the oxidation of dioxane lignins were deprotonated 2,6-dimethoxyp-benzosemiquinone and 6-hydroxy-2-methoxy-p-benzosemiquinone, and that they were produced from syringyl end groups. The production rate of radicals from syringyl end groups possessing anα-carbonyl group was greater than that possessing anα-hydroxyl group. It was suggested that stilbene-type syringyl end groups were produced from phenylcoumaran moieties in lignins by acidolysis. The radicals produced from guaiacyl end groups were not observed by the oxidation process.
Bibliography:2001000931
Q60
ISSN:1435-0211
1611-4663
DOI:10.1007/BF00581313