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题名	纤维素在离子液体中的再生和酯化研究
作者	曹妍
学位类别	博士
答辩日期	2008-07-11
授予单位	中国科学院过程工程研究所
授予地点	过程工程研究所
导师	张懿
关键词	离子液体 纤维素 秸秆纤维素 再生 均相酯化
其他题名	Research of Cellulose Regeneration and Esterification in Ionic liquids
学位专业	化学工艺
中文摘要	随着化石能源的逐渐枯竭和温室效应的日益加剧，寻求替代资源已经成为人类可持续发展的重要目标，从可再生资源特别是天然生物质资源生产高附加值化工产品正在成为许多国家的战略需求和科学研究的热点领域。纤维素是地球上储量最丰富的可再生天然生物质资源，以其为原料可以制备用途广泛的再生纤维素和纤维素衍生物材料。本论文针对目前生产纤维素化学品（包括再生纤维素和纤维素衍生物）工艺对环境污染严重的问题，研究开发了基于绿色溶剂离子液体的新工艺，从离子液体的合成出发，考察了不同来源的纤维素（包括秸秆纤维素、木桨粕、微晶纤维素等）在离子液体中的溶解再生和均相酯化反应，对制备的再生纤维素和纤维素酯产品进行了结构、性能的分析和表征，并与现有工艺、产品性能进行对比。研究中取得的主要成果和创新点如下： 1、以玉米秸秆纤维素为原料在离子液体1-烯丙基-3-甲基咪唑氯盐（AMIMCl）和1-乙基-3-甲基咪唑醋酸盐（EMIMAc）中制备了再生秸秆纤维素膜。采用FTIR、XRD、SEM、力学、热力学测试等现代表征手段对产品结构和性能进行了分析。在溶解温度为80℃，溶解时间为4h的条件下，从AMIMCl和EMIMAc中制备的再生秸秆纤维素膜的拉伸强度分别为112MPa和47MPa，与以桨粕为原料在离子液体中制备的再生纤维素膜的力学性能非常接近。 2、研究了纤维素在AMIMCl离子液体中的均相乙酰化，包括三个部分：①玉米秸秆纤维素在AMIMCl中的均相乙酰化； ②AMIMCl溶液中高浓度纤维素的均相乙酰化；③低取代度醋酸纤维素在AMIMCl中的均相法合成。研究表明，在不加任何催化剂的条件下，直接使用乙酸酐作为酰化试剂，通过控制反应时间、温度和计量比（乙酸酐与纤维素分子链重复单元AGU的摩尔比）就可以得到部分或完全取代的醋酸纤维素（CA）。特别是取代度值在2.0～2.7之间的CA可以完全溶解在丙酮中，这在其他均相体系（如BMIMCl）中是无法实现的。 3、在AMIMCl中均相一步法制备了丁酰基质量百分含量在6～47％的醋酸丁酸纤维素（CAB），对产品进行了FTIR、NMR、溶解性能等表征，发现丁酰基的质量百分含量在33～47％之间的CAB可以溶解在甲乙酮、乙酸乙酯、乙酸丁酯、二氯甲烷等工业常用的有机溶剂中。 4、通过简单操作就可以回收离子液体。水中离子液体的回收率最高可以达到99.9％；而冰醋酸与AMIMCl的混合溶液分离后AMIMCl中也只有2%左右的醋酸。 本论文的结果表明，离子液体不仅是纤维素的优良溶剂，还是优良的纤维素均相酯化介质，在对多种来源纤维素（尤其是秸秆纤维素）的溶解再生以及均相酯化反应中取得了很好的效果。以离子液体为介质的纤维素均相衍生化体系不仅具有产物均一、反应可控、反应效率高等优点，还具有溶剂易于回收、可循环使用的特点，有望解决现有工艺中的重污染问题。
英文摘要	Based on the increasingly exhaustion of fossil based energy and the severity of greenhouse effect, searching for substituted resource or energy has become the important object for human being’s sustainable development, and producing high value chemical products from the reproducible resource, especially the natural biomass resource, is turning to be the main developing strategy in many countries and hot filed in scientific research. Cellulose is the most abundant polymer in the world, from which the widely used regenerated cellulose and cellulose derivatives can be made. Because of the environmental pollution problem of traditional cellulose production technology, new technology based on the “green solvent” ——ionic liquids was studied in this work. We set out from the synthesis of ILs, and studied the regeneration and esterification of cellulose in IL. The major results obtained in the study include the followings: 1、Regenerated cellulose films from cornhusk were prepared in two ionic liquids, AMIMCl and EMIMAc. The structure and properties of the regenerated cornhusk cellulose films was investigated by FTIR、XRD、SEM、thermal and strength test. The results indicate that at the dissolving condition of 80℃, 4h, the tensile strength of the regenerated cornhusk cellulose films prepare from AMIMCl and EMIMAc can reach as high as 112MPa and 47MPa respectively. 2、The homogeneous acetylation of plant cellulose in AMIMCl were studied. Three parts were included: ①the homogeneous acetylation of cornhusk cellulose in AMIMCl; ②the homogeneous acetylation of cellulose in relatively high cellulose/ AMIMCl solution; ③the synthesis of cellulose acetate (CA) with low substitution degree homogeneously in AMIMCl. Without using any catalyst, partial and full substituted CA could be prepared in one-step just by controlling of the reaction time, temperature and molar ratio of acetic anhydride/ anhydroglucose unit (AGU) in cellulose. Especially, the CA synthesis in AMIMCl with the DS range from 2.0 to 2.7 exhibit good solubility in acetone, which can not realized in other homogeneous system, such as BMIMCl. 3、Cellulose acetate butyrate (CAB) with the butyl content range from 6~47wt% was homogeneously synthesized in AMIMCl. The synthesized CAB were characterized by means of FTIR，NMR, solubility and thermal test. The results showed that, the obtained CAB with butyryl content bigger than 30% shows good dissolving ability in 2-methyl-ethyl ketone, 1,2-dichloromethane, acetyl acetate and butyl acetate 4、The IL can be easily recycled after the regeneration and esterification of cellulose. From the AMIMCl aqueous solution, more than 99.9% of AMIMCl could be recycled, and there will leave only 2% acetic acid after isolation of acetic acid from AMIMCl. Above results show that the IL, AMIMCl, is not only an excellent solvent of cellulose, but also a good medium for cellulose homogeneous esterification, for good results can be obtained in the process of cellulose regeneration and esterification. Not only the IL/cellulose homogeneous system has advantages in product uniformity, reaction control, and reaction efficiency, but also the solvent is easy to be recycled and reused. It is possible to solve the pollution problem in the current technology.
语种	中文
公开日期	2013-09-13
页码	141
内容类型	学位论文
源URL	[http://ir.ipe.ac.cn/handle/122111/1251]
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	曹妍. 纤维素在离子液体中的再生和酯化研究[D]. 过程工程研究所. 中国科学院过程工程研究所. 2008.

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