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Semi-quantitative method to evaluate the alpha-carbonyl content in lignin

Journal of wood science, 2005-04, Vol.51 (2), p.172-175 [Peer Reviewed Journal]

Journal of Wood Science is a copyright of Springer, (2005). All Rights Reserved. ;ISSN: 1435-0211 ;EISSN: 1611-4663 ;DOI: 10.1007/s10086-004-0627-1

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Title:
Semi-quantitative method to evaluate the alpha-carbonyl content in lignin
Author: Tomoda, I. (Tokyo Univ. (Japan)) ; Matsumoto, Y ; Meshitsuka, G
Subjects: BLEACHING ; CARBONYL COMPOUNDS ; carbonyl structure ; Carbonyls ; Caustic soda ; chemical reactions ; CHEMICAL STRUCTURE ; Deuterium ; HYDROGEN PEROXIDE ; hydroxides ; hydroxymethine ; kraft pulp ; Lignin ; LIGNINS ; Lithium hydroxides ; methodology ; nitrobenzene oxidation ; Oxidation ; PULP ; pulp and paper technology ; quantitative analysis ; Reaction mechanisms ; sodium borodeuteride ; Sodium hydroxide ; Vanillin ; wood pulp
Is Part Of: Journal of wood science, 2005-04, Vol.51 (2), p.172-175
Description: A method to estimate the content of alpha-carbonyl structures in lignin was developed. This method consists of two successive treatments: NaBD sub(4) treatment of pulp to reduce an alpha-carbonyl structure in lignin, and nitrobenzene oxidation. NaBD sub(4) was used to convert an alpha-carbonyl structure to a deuterium-labeled hydroxymethine structure. The ratio of D-vanillin [(HO)(H sub(3)CO)C sub(6) H sub(3)CDO] to H-vanillin [(HO)(H sub(3)CO)C sub(6) H sub(3) CHO] or that of their syringyl analogues obtained by nitrobenzene oxidation was used as the measure of the content of alpha-carbonyl structure. Model experiments demonstrated that when sodium hydroxide was used as alkali for the nitrobenzene oxidation, the retention of deuterium at the side chain alpha-position was very low due to the displacement of deuterium with hydrogen by an unknown reaction mechanism. In order to depress this unexpected displacement, the reaction conditions of the nitrobenzene oxidation were modified. The modified nitrobenzene oxidation employs 0.5mol/l of lithium hydroxide as a reaction medium instead of 2.0mol/l sodium hydroxide. By this modification, this method could successfully trace the formation and the degradation of the alpha-carbonyl structure in milled wood lignins.
Publisher: Heidelberg: Springer Nature B.V
Language: English
Identifier: ISSN: 1435-0211
EISSN: 1611-4663
DOI: 10.1007/s10086-004-0627-1
Source: Alma/SFX Local Collection
ProQuest Central

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Semi-quantitative method to evaluate the alpha-carbonyl content in lignin

Journal of Wood Science is a copyright of Springer, (2005). All Rights Reserved. ;ISSN: 1435-0211 ;EISSN: 1611-4663 ;DOI: 10.1007/s10086-004-0627-1

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