HEXA AND SOME CARBOHYDRATE CHROMOPHERES IN UNBLEACHED AlKALINE PULP OF REED

摘要

By means of selective hydrolysis with sodium formate solution and UV-spectrometer, hexenuronic acid groups (HexA) and other chromopheric groups from carbohydrates in unbleached Soda-green-oxygen pulp (i.e. alkaline pulp) of reed are studied. Then metal ions in the pulp are determined with atomic absorption spectrometer. The results show that, in addition to HexA, there are some chromopheres originated in carbohydrates. The HexA content for alkaline reed pulp is much lower than that in Kraft wood pulp. The retention of Fe, Mn, etc in reed pulp is not related to the HexA in reed pulp. Pretreatment with hot diluent acid can significantly degrade all above chromopheres, resulting in an obvious improving on oxygen bleaching efficency of reed pulp. The HexA and other chromopheric groups are remarkbly degraded during conventional oxygen bleaching.