Dissolution of Lignin in Kraft Pulp by Oxygen Bleaching
作者:
Per Larsson,
Olof Samuelson,
期刊:
Journal of Wood Chemistry and Technology
(Taylor Available online 1993)
卷期:
Volume 13,
issue 2
页码: 237-259
ISSN:0277-3813
年代: 1993
DOI:10.1080/02773819308020516
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
Gel permeation chromatography of spent liquors from oxygen bleaching showed that cleavage of covalent linkages in the fiber was a prerequisite for the dissolution of the lignin. The reactions continued in the liquor phase. The cleavage was related to the oxidation of the lignin. With pulps pretreated with nitrogen dioxide an appreciable number of lignin linkages were cleaved also by the direct influence of the hydroxide ions on the nitrated lignin. In the alkaline medium the acidic sites in the fiber and in dissolved lignin fragments are ionized. Donnan-exclusion and an increased fiber swelling promote the transfer of the fragments into the liquor. Hydrophilic groups introduced into the lignin during oxygen bleaching promote the delignification.
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