On the structural significance of the kappa number measurement
1998 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, Vol. 13, no 2, 153-158 p.Article in journal (Refereed) Published
The structural significance of a kappa number has been studied by quantifying the permanganate consumption of various isolated pine, birch and poplar lignins, of lignin model compounds and of carbohydrate and other aliphatic compounds under kappa number measurement conditions. It was found that the average permanganate consumption for the different lignins was 11-12 equivalents per phenylpropane unit. This value is in accordance with the addition of permanganate ion to all three double bonds in the aromatic rings regardless of whether these are phenolic or non-phenolic or whether they belong to a guaiacyl or a syringyl unit. It was further found that permanganate can be consumed by other types of oxidizable structures like aliphatic double bonds, aldehyde groups and alpha-keto-carboxylic acid groups. For unbleached kraft pulp samples, the combined consumption of permanganate by lignin and hexenuronic acid groups from xylan was found to be fairly close to the measured kappa number. The small discrepancies found indicate, however, that other types of structures may contribute to the kappa number.
Place, publisher, year, edition, pages
1998. Vol. 13, no 2, 153-158 p.
kappa number, kraft pulps, soda pulps, lignin, carbohydrates, uronic acids, permanganate consumption, HEXENEURONIC ACID GROUPS, KRAFT, PERMANGANATE, COOKING, LIGNINS, XYLAN, PULPS
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-12988ISI: 000081970700011OAI: oai:DiVA.org:kth-12988DiVA: diva2:320009