木材离子液体中的溶解再生及均相乙酰化基础研究
文献类型：学位论文
| 作者 | 王学静 |
| 学位类别 | 硕士 |
| 答辩日期 | 2011-05-15 |
| 授予单位 | 中国科学院研究生院 |
| 导师 | 唐清 ; 李会泉 |
| 关键词 | 离子液体 木材 溶解 再生 乙酰化 纤维素 |
| 其他题名 | Dissolution, Regeneration and Homogeneous Acetylation of Wood Chip in Ionic Liquids |
| 学位专业 | 化学工艺 |
| 中文摘要 | 化石能源的日益消耗和随之产生的环境污染问题，使可再生生物质资源的利用越来越受到世人关注。木材作为自然界中储量最丰富的可再生生物质资源之一，在国民生活和生产中有极为广泛的用途。本研究针对目前木材处理加工工艺中资源消耗大、环境污染严重的问题，研究开发了基于离子液体的木材转化利用新工艺，深入考察了木材在离子液体1-烯丙基-3-甲基咪唑氯盐（AmimCl）中的溶解再生和均相乙酰化反应，采用13C CP/MAS NMR、FT-IR、XRD、TGA、SEM等手段对再生、酰化木材产品进行了结构、性能分析表征。主要研究内容与进展如下： 1. 研究了松木、杨木、梧桐、楸木四种木材在AmimCl中的溶解与再生行为，考察了溶解时间、温度、浓度、微波等工艺条件对木材溶解率、再生率的影响。研究结果表明四种木材在AmimCl中均可实现部分溶解，其中松木的溶解再生效果最佳；最优条件下，松木的溶解率和再生率分别可达50％和36％，再生松木的纤维素纯度可达85％。分析结果表明，木材经离子液体处理后变为无定性态多孔结构，说明离子液体破坏了木材分子内和分子间的氢键；再生松木中纤维素含量最高，呈致密均匀的膜状结构。 2. 研究了AmimCl中松木的乙酰化反应，实现了不外加催化剂条件下，松木的全组分直接乙酰化。考察了反应时间、温度、酰化剂配比等工艺条件对松木乙酰化反应的影响规律，酰化松木重量增加比（WPG）最高可以达到156％。分析结果表明，木材中纤维素和木质素均发生了乙酰化反应，乙酰化木材呈现由细小颗粒堆积的粉末结构，并保持了良好的热稳定性。 3. 研究了溶解再生及乙酰化后离子液体的再生循环，研究结果表明通过活性炭吸附、抽滤、旋蒸和干燥等简单操作手段可实现离子液体回收，回收的离子液体经1H NMR和FT-IR表征没有结构变化。使用回收的离子液体进行了木材的溶解再生及乙酰化性能研究表明，回收和新鲜离子液体中得到的再生、酰化木材的结构性能一致。 |
| 英文摘要 | Wood is one of the most abundant renewable resources in the world and shows widely applications in the national life and industry. Because of the enormous reagent consumption and environmental pollution problems involved in traditional wood processing technology, new technology based on the "green solvent"--ionic liquids was studied in this work. The dissolution, regeneration and acetylation of wood chip in the ionic liquid 1-ally-3-methylimidazolium chloride (AmimCl) were studied. The structure and properties of the regenerated and acetylated pine wood was characterized by 13C CP/MAS NMR, FT-IR, XRD, TGA and SEM. The major results are included in the followings: 1. Wood can be partially dissolved in AmimCl, and pine is the most suitable wood for dissolution and regeneration in AmimCl among the chosen four kind of wood (pine, poplar, Chinese parasol, and catalpa). Wood dissolution and regeneration can be enhanced with the increase of time and temperature and the decrease of initial concentration. Under the optimized condition, the dissolution and regeneration rate can reach 50% and 36% respectively for pine, and its cellulose content can reach as high as 85% as well. 13C CP/MAS NMR and FT-IR shows the majority of the regenerated pine is cellulose with a small amount of hemicelluloses and lignin; XRD shows that fully amorphous material is obtained after regeneration of pine from IL, revealing that the IL destroys the inter- and intra-molecular hydrogen bond among lignocelluloses; SEM shows that the structure of wood changes from a relatively fascicular texture to a highly porous structure after ionic liquid processing, and the regenerated wood shows a homogeneous, dense and uniform macrostructure in free surface. 2. The homogeneous acetylation of pine wood in AmimCl is successful without adding any catalyst. Weight Percent Gain (WPG) of acetylation wood increased with increasing the reaction time，temperature and the molar ratio of Ac2O/hydroxy of pine wood，the highest WPG can reach to 156%. 13C CP/MAS NMR and FT-IR verified the acetylation of pine in AmimCl; TGA shows the acetylated wood have superior thermal stability compared with original pine wood；SEM shows the acetylated wood exhibits homogeneous pulverous structure compared to the fascicular texture of original wood. 3．After dissolution, regeneration and acetylation of wood, the IL can be easily recycled and reused. 1H NMR and FT-IR shows that no chemical structure changed in the recycled IL(RIL) comparing with the fresh IL. The RIL is used in the dissolution, regeneration and acetylation of wood, 13C CP/MAS NMR，FT-IR，XRD，and SEM show that the properties and structure of the regenerated and acetylated wood obtained from the RIL is just as same as that obtained from the fresh IL. |
| 语种 | 中文 |
| 公开日期 | 2013-09-24 |
| 页码 | 72 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1745]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 王学静. 木材离子液体中的溶解再生及均相乙酰化基础研究[D]. 中国科学院研究生院. 2011. |
入库方式： OAI收割
来源：过程工程研究所
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