title: Hemicelluloses prior to aspen chemithermomechanical pulping: pre-extraction, separation, and characterization.
abstract: A portion of hemicelluloses and acetic acid can be pre-extracted with dilute sulfuric acid prior to the aspen chemithermomechanical pulp process. The streams collected from the second press-impregnation stage after acid pre-extraction contain a significant amount of acid pre-extracted hemicelluloses. Most of the total sugars obtained from the pressate were xylan, in which xylan was further hydrolyzed to sugar monomers under the acid pre-extraction condition. To fully understand the characteristics of hemicelluloses yielded prior to pulping, the pre-extracted hemicelluloses were separated and characterized by FT-IR, (1)H NMR, and thermogravimetric analysis in this study. Most of the FT-IR bonds from the hemicelluloses agreed well with the other two spectra of birch xylan and CA0050 xylan, except a new absorption at 1734 cm(-1) contributed to acetyl groups. The hemicelluloses obtained from acid pre-extraction began to decompose significantly at about 225 °C, slightly lower in comparison with organosolv and alkaline hemicelluloses reported in the literature.
authors.affiliation: Tianjin Key Laboratory of Pulp & Paper, Tianjin University of Science & Technology, Tianjin, China 300457.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Qingxi
authors.initials: Q
authors.lastname: Hou
authors.forename: Changbin
authors.initials: C
authors.lastname: Mao
authors.forename: Zhirun
authors.initials: Z
authors.lastname: Yuan
authors.forename: Kecheng
authors.initials: K
authors.lastname: Li
mesh_terms: D029662:Betula / Q000737:chemistry*; D001709:Biotechnology; D005591:Chemical Fractionation; D006868:Hydrolysis; D010936:Plant Extracts / Q000737:chemistry* / Q000302:isolation & purification*; D011134:Polysaccharides / Q000737:chemistry* / Q000302:isolation & purification*; D013464:Sulfuric Acids / Q000737:chemistry; D014934:Wood / Q000737:chemistry*
chemical_list: D010936:Plant Extracts; D011134:Polysaccharides; D013464:Sulfuric Acids; C007916:hemicellulose; C033158:sulfuric acid