The Role of Carbohydrates in Alkali Anthraqutnone Pulping
作者:
Tapani Vuorinen,
期刊:
Journal of Wood Chemistry and Technology
(Taylor Available online 1993)
卷期:
Volume 13,
issue 1
页码: 97-125
ISSN:0277-3813
年代: 1993
DOI:10.1080/02773819308020509
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
The reactions of carbohydrates with anthraquinones in alkaline pulping processes are reviewed. AQ reacts mainly with the short-lived intermediates that are formed in the degradation reactions of wood polysaccharides. Oxidation of the reducing end groups of polysaccharides to stable aldonic acid end groups is marginal and corresponds to less than 1 % of all reactions of AQ. The stabilization of the polysaccharides may be enhanced by the use of salts of alkaline earth metals which increase the relative oxidation rate of sugar enediols and promote the hydride shift reaction of the intermediate aldos-2-ulose end groups to stable hexonic acid end groups. Analysis of the monomeric carbohydrate-derived oxidation products indicates that hardwood lignin probably contains more structures that react with anthrahydroquinone than does softwood lignin. This difference may partly explain the more facile delignification of hardwoods.
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