Performance of Side-Streams from Eucalyptus Processing as Sources of Polysaccharides and Lignins by Kraft Delignification

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• 作者：Paula C. R. Pinto ; Cátia Oliveira ; Carina A. E. Costa ; Alírio E. Rodrigues
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2016
• 出版时间：January 20, 2016
• 年：2016
• 卷：55
• 期：2
• 页码：516-526
• 全文大小：478K
• ISSN：1520-5045

文摘

The performance of bark, branches, sawdust, forest biomass, and short-rotation eucalyptus in kraft delignification to produce polysaccharides and lignin is reported and discussed. A positive correlation was found between pulping severity required for delignification and lignin reactivity. Among all, branches feedstock is the best source of polysaccharides due to the high pulp yield (48–54%) with a satisfactory delignification degree. Branches lignin was characterized for the first time, evaluating syringyl/guaiacyl/p-hydoxyphenyl (65:22:13), β-O-4 units (71/100C₆) and condensed structures (12%). Kraft lignins (KL) were isolated from black liquors, including industrial one, and analyzed by NMR demonstrating remarkable differences. Among all, bark KL reveals the highest depolymerization (lowest β-O-4 content, 18/100 C₆) and condensation (50%) as a consequence of higher active alkali required for pulping. Sawdust and branches KLs have similar degree of condensation, but the former revealed slightly less β-O-4 (25/100 C₆) and more hydroxyl phenolic groups (6.6 mmol/g) than branches KL (28/100C₆, 5.9 mmol/g).