Fractionation of Lignocellulosic Materials Using Ionic Liquids: Part 2. Effect of Particle Size on the Mechanisms of Fractionation

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• 作者：Timo Leskinen ; Alistair W. T. King ; Ilkka Kilpel盲inen ; Dimitris S. Argyropoulos
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2013
• 出版时间：March 20, 2013
• 年：2013
• 卷：52
• 期：11
• 页码：3958-3966
• 全文大小：315K
• 年卷期：v.52,no.11(March 20, 2013)
• ISSN：1520-5045

文摘

In part 1 of this effort ( Ind. Eng. Chem. Res.pan class="NLM_x"> pan>2011pan class="NLM_x">, pan>50pan class="NLM_x">, pan>12349鈭?2357), we studied how wood dissolved in ionic liquid (IL) is precipitated into different molecular weight ranges upon the addition of a cosolvent. In this article, we further analyze the chemical compositions of these fractions and elucidate the mechanisms of fractionation. Specifically, we fractionated Norway spruce wood solvated with 1-allyl-3-methylimidazolium chloride ([amim]Cl) and analyzed the resulting fractions by Klason lignin analysis and FT-IR and NMR spectroscopies. We found that separation of the different components can be tuned by the variable dissolution of wood based on particle size, resulting from preparatory milling. It is possible to obtain cellulose-rich material with a relatively low (6.2%) lignin content, from spruce sawdust. This can achieved by extracting the cellulose from the insoluble lignin鈥揷arbohydrate complex (LCC) matrix. Extensive milling of wood afforded a soluble LCC matrix, and its precipitation was based on molecular weight and not on chemical composition. Indications of the presence of LCCs in the hemicellulose fraction were obtained by utilizing multidimensional NMR spectroscopy.