Hemicelluloses Prior to Aspen Chemithermomechanical Pulping: Pre-Extraction, Separation, and Characterization
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- 作者：Wei Liu ; Qingxi Hou ; Changbin Mao ; Zhirun Yuan ; Kecheng Li
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2012
- 出版时间：May 16, 2012
- 年：2012
- 卷：60
- 期：19
- 页码：4880-4885
- 全文大小：311K
- 年卷期：v.60,no.19(May 16, 2012)
- ISSN：1520-5118
文摘
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, 1H 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鈥? contributed to acetyl groups. The hemicelluloses obtained from acid pre-extraction began to decompose significantly at about 225 掳C, slightly lower in comparison with organosolv and alkaline hemicelluloses reported in the literature.