Alkaline steeping of dissolving pulp. Part II: Soluble compounds in the press lye

• Published in: Cellulose (London) Vol. 21; no. 4; pp. 2889 - 2900
• Main Authors: Mozdyniewicz, Danuta Joanna, Schild, Gabriele, Sixta, Herbert
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer-Verlag 2014; Springer Netherlands; Springer Nature B.V
• Subjects: Beech; Bioorganic Chemistry; Bleaching; cellulose; Ceramics; Chemistry; Chemistry and Materials Science; Chlorine; Composites; Degradation; dissolving pulp; Fagus; Glass; Hydroxy acids; Mass distribution; molecular weight; Natural Materials; Organic Chemistry; Original Paper; Physical Chemistry; Polymer Sciences; soaking; Sodium hydroxide; Steeping; Sugar; Sulfite pulp; Sulfuric acid; Sustainable Development; temperature; xylan; Hydroxy acids; Hemicellulose; Steeping; Degradation products; Viscose process; Dissolving pulp
• ISSN: 0969-0239; 1572-882X
• DOI: 10.1007/s10570-014-0291-6

This work describes the comprehensive characterization of the degradation products obtained after the alkaline steeping of dissolving pulp. Total chlorine free bleached beech sulfite pulp was treated with 18 % sodium hydroxide at different temperatures (40, 50 and 60 °C) for time periods of up to 80 h. After the removal of the insoluble cellulose, the remaining alkali solution was treated with sulfuric acid to precipitate the β-fraction. With extended treatment times and temperatures, the proportion of xylan in the β-fraction is increased. However, the molar mass distribution and the amount of 4-O-methylglucuronic acid in the β-fraction revealed no clear trend as a function of the treatment conditions. In total 13 hydroxy acids were identified in the acid soluble γ-fraction, of which glucoisosaccharinic, glycolic, lactic and xyloisosaccharininc acids were among the most abundant hydroxy acids representing the degradation products from C6- and C5-sugars.