The Condensation Reactions of Lignin Model Compounds in Alkaline Pulping Liquors
作者:
TerryJ. Fullerton,
期刊:
Journal of Wood Chemistry and Technology
(Taylor Available online 1987)
卷期:
Volume 7,
issue 4
页码: 441-462
ISSN:0277-3813
年代: 1987
DOI:10.1080/02773818708085279
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
The significance of condensation reactions at the 5-position of the aromatic ring of lignin to the overall pulping process has been evaluated using lignin model compounds. Reactions of 5-hydroxymethylcreosol, as a model for 5-substituted lignins formed when formaldehyde is released during pulping, have shown that such groups will react viaortho-quinonemethides to give alkali-stable carbon-carbon bonded condensation products. The amount of condensation depends on the type of pulping liquor used, with less formed in the kraft and soda-anthraquinone (AQ) processes than in the soda process. In these liquors the hydrosulphide or anthrahydroquinone (AHQ) ions present can compete effectively with phenoxide ion for the reactiveo-quinonemethide intermediate.
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