Complete dissolution and partial delignification of wood in the ionic liquid 1-ethyl-3-methylimidazolium acetate
Complete dissolution and partial delignification of wood in the ionic liquid 1-ethyl-3-methylimidazolium acetate
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DOI：
10.1039/b822702k
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发表时间：
2009-01-01
期刊：
影响因子：
9.8
通讯作者：
Rogers, Robin D.
中科院分区：
文献类型：
--
作者：
Sun, Ning;Rahman, Mustafizur;Rogers, Robin D.
软木（南方黄松）和硬木（红橡木）在温和研磨后都可以完全溶解在离子液体1-乙基-3-甲基咪唑乙酸盐（[C（2）mim] OAc）中。通过在油浴中加热样品来实现完全溶解，尽管木材溶解可以通过微波脉冲或超声辐照来加速。研究表明，[C（2）mim] OAc是比氯化1-丁基-3-甲基咪唑鎓（[C（4）mim] Cl）更好的木材溶剂，木材类型、初始木材负载、粒度等变量会影响溶解和溶解速率;例如，红橡木比南方黄松溶解得更好、更快。无碳水化合物的木质素和富含纤维素的材料可以通过使用适当的重构溶剂（例如，丙酮/水1：lv/v），并且在一个溶解/重构循环中实现了重构的富含纤维素的材料（分别来自松木和橡木）中木质素含量的约26.1%和34.9%的降低。再生的富含纤维素的材料和木质素馏分进行了表征，并与原始木材样品和生物聚合物标准进行了比较。对于松树，59%的综纤维素（即，原始木材中的纤维素和半纤维素的总和）可以在富含纤维素的重构材料中回收;而在富含纤维素的材料中，分别有31%和38%的原始木质素作为无碳水化合物的木质素和作为碳水化合物结合的木质素回收。
Both softwood (southern yellow pine) and hardwood (red oak) can be completely dissolved in the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C(2)mim]OAc) after mild grinding. Complete dissolution was achieved by heating the sample in an oil bath, although wood dissolution can be accelerated by microwave pulses or ultrasound irradiation. It has been shown that [C(2)mim] OAc is a better solvent for wood than 1-butyl-3-methylimidazolium chloride ([C(4)mim]Cl) and that variables such as type of wood, initial wood load, particle size, etc. affect dissolution and dissolution rates; for example, red oak dissolves better and faster than southern yellow pine. Carbohydrate-free lignin and cellulose-rich materials can be obtained by using the proper reconstitution solvents (e.g., acetone/water 1 : 1 v/v) and approximately 26.1% and 34.9% reductions of lignin content in the reconstituted cellulose-rich materials (from pine and oak, respectively) have been achieved in one dissolution/reconstitution cycle. The regenerated cellulose-rich materials and lignin fractions were characterized and compared with the original wood samples and biopolymer standards. For pine, 59% of the holocellulose (i.e., the sum of cellulose and hemicellulose) in the original wood can be recovered in the cellulose-rich reconstituted material; whereas 31% and 38% of the original lignin is recovered, respectively, as carbohydrate-free lignin and as carbohydrate-bonded lignin in the cellulose-rich material.