|
| << vorige | volgende >> |
Tijdschrift beschrijving
Alle jaargangen van het bijbehorende tijdschrift
Alle afleveringen van het bijbehorende jaargang
Alle artikelen van de bijbehorende aflevering
Details van artikel 5 van 9 gevonden artikelen
| Titel: |
Chemical Linkage of Polysaccharides to Residual Lignin in Loblolly Pine Kraft Pulps |
| Auteur: |
Minor, J. L. |
| Verschenen in: |
Journal of wood chemistry and technology |
| Paginering: | Jaargang 6 (1986) nr. 2 pagina's 185-201 |
| Jaar: |
1986 |
| Inhoud: |
The chemical bonding of polysaccharides to the residual lignin remaining in bleachable grade loblolly pine (Pinus taeda) kraft pulp was examined by methylation analysis. Before analysis, most of the nonbonded polysaccharides were enzymatically hydrolyzed and the sugars were washed from the remaining solid to give a residual lignin that contained about 8% carbohydrates. The analysis indicated that the majority of the remaining sugars were present as oligomeric segments of well-characterized pulp polysaccharides. About one monomeric unit per oligomer was bonded to lignin. The methylation data indicated that the major bonding was to the primary C-6 position in hexans and the primary C-5 position in arabinan. Xylan was bonded to lignin at C-3 with a small amount at C-2. The overall pattern and quantity of bonding was sufficiently similar to that previously determined for Pinus taeda wood to conclude that formation of alkali-stable, acid-hydrolyzable lignin-carbohydrate bonds is not significant during kraft pulping. The predominant methylated derivatives obtained from galactose and arabinose indicated 1-4 and 1-5 linkages, respectively. This is characteristic of pectic galactan and arabinan structures. It is especially interesting that these structures, which were previously noted with the wood lignin, were carried through the pulping process. They appear to be intimately associated with the lignin polymer. Arabinan, galactoglucomannan, and galactan were solubilized when the residual pulp enzyme lignin was oxidized with sodium chlorite. The insoluble cellulose, glucomannan and arabinoxylan oligomers no longer contained units bonded to lignin. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 5 van 9 gevonden artikelen
| << vorige | volgende >> |