THE INFLUENCE OF THE BLEACHING MEDIUM ON CHLORINE DIOXIDE DELIGNIFICATION

Autor:	Brian N. Brogdon, Donald R. Dimmel, Thomas Joseph McDonough
Rok vydání:	2001
Předmět:	Chlorine dioxide Muconic acid Aqueous solution Ethanol Chemistry General Chemical Engineering Sodium chemistry.chemical_element General Chemistry Kappa number Quinone chemistry.chemical_compound Lignin Organic chemistry General Materials Science Nuclear chemistry
Zdroj:	Journal of Wood Chemistry and Technology. 21:143-156
ISSN:	1532-2319 0277-3813
DOI:	10.1081/wct-100104224
Popis:	Chlorine dioxide delignification (D0) stages performed in 90% ethanol resulted in post-D0 kappa numbers that were 2 to 2.5 units lower than those performed in water. In spite of the reduction in kappa number, various gravimetric and UV spectroscopic techniques for measuring residual lignin indicated that the ethanol medium did not significantly enhance D0 stage lignin removal. Differences in post-D0 kappa numbers between the ethanol-based and aqueous systems were ascribed to how the bleaching medium affects ClO2 oxidation of residual lignin. Ethanol-based D0 stages resulted in an oxidized lignin that contains fewer muconic acid structures and more quinone structures than the aqueous-based systems. Indirect evidence from sodium hydrosulfite reduction implied that quinone moieties consume less KMnO4 than aromatic structures in lignin during the kappa number test.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::4b6092fa88268ec3e392c2e8d53f1944 https://doi.org/10.1081/wct-100104224 Zobrazit plný text záznamu