The Contribution to Kappa Number from Hexeneuronic Acid Groups in Xylan of Wheat Straw Kraft Pulp

摘要

The 4-O-methylglucuronic acid side-groups attached to the xylan main chain in native materials can be converted to hexeneuronic acid groups in the high temperature and alkaline condition. The presence of hexeneuronic acid groups in pulp results in increased consumption of potassium permanganate in the kappa number determination. The content of hexeneuronic acid groups in wheat straw Kraft pulp is around 10 μ mol/g, much lower than that in wood Kraft pulp (especially in hardwood pulps).