马尾松树皮在离子液体中的溶解及组分分离研究

Study on the Dissolution and Fractionation of Pinus Massoniana Bark in Ionic Liquid

中文关键词:  离子液体  马尾松树皮  组分分离  木质纤维素

Key Words:ionic liquid  Pinus massoniana bark  fractionation  lignocellulose

中文摘要:

      针对目前树皮组分难以有效利用的问题，以离子液体1-烯丙基-3-甲基咪唑氯盐（［Amim］Cl）为溶剂，对球磨后的马尾松（Pinus massoniana L.）树皮进行溶解，随后以NaOH溶液及乙醇为沉淀剂，对树皮中的纤维素、木质素和半纤维素组分进行分级分离。结果表明，球磨24 h后的马尾松树皮在100℃、溶解5 h的条件下，能够在离子液体中完全溶解；再生后树皮中纤维素的晶型由I型转变为II型，结晶度降低，但再生后树皮主要化学成分与原料相同。采用1% NaOH溶液及乙醇溶液处理溶解后的树皮可有效分离得到纤维素、木质素和半纤维素，分离后各组分的化学结构未发生明显改变。离子液体经5次循环再利用后，其回收率依旧可以保持90%以上。

Abstract:

      The ball-milled Pinus massoniana （Pinus massoniana L.） bark was dissolved in ionic liquid—1-allyl-3-methylimidazolium chloride （［Amim］Cl） and subsequently fractionated from the bark to cellulose， lignin， and hemicellulose using dilute alkali and ethanol solution as the precipitant. The results showed that Pinus massoniana bark could be completely dissolved in ［Amim］Cl at 100℃ for 5 h after 24 h of ball milling. After regeneration， the cellulose crystal form of the bark was changed from type I to type II with decreased crystallinity while the chemical structure of each component in the bark did not change. Cellulose， hemicellulose， and lignin could be fractionated by treating the abovementioned dissolved bark with 1% NaOH and ethanol solution with negligible change in the chemical structure of each component. After recycled and reused for 5 times， the ionic liquids maintained a recovery rate above 90%.