QQ客服 官方微博 反馈留言

题名	离子液体催化环状碳酸酯合成及其水解应用基础研究
作者	孟震英
学位类别	博士
答辩日期	2010-06-10
授予单位	中国科学院研究生院
授予地点	北京
导师	张锁江
关键词	乙二醇 离子液体 环状碳酸酯 催化 水解
其他题名	Study on the synthesis and hydrolysis of cyclic carbonates catalyzed by ionic liquids
学位专业	应用化学
中文摘要	碳酸乙烯酯法合成乙二醇是乙二醇生产新技术中一种能耗低、收率高和选择性好的路线，但其目前仍存在催化剂稳定性差、活性低、反应条件苛刻等问题。本工作针对这些问题，开展了离子液体催化合成环状碳酸酯及其水解过程的研究，并将离子液体应用到碳酸乙烯酯法合成乙二醇的节能工艺中。论文主要创新性工作及成果如下： 1. 将氯化胆碱与Lewis酸金属卤化物复合作为CO2和环状碳酸酯合成的均相催化剂。结果表明，在CH/ZnBr2复合催化剂催化下，在110 ℃、1.5MPa CO2、1 h内，碳酸丙烯酯的收率大于96 %。此外，催化剂容易回收利用，反应结束后，通过简单蒸馏就能用于下一轮反应，催化剂循环使用五次，碳酸丙烯酯的收率仍然保持在99 %左右；该催化体系同样适用于其他端位环氧化合物；在此基础上，提出了可能的反应机理。 2. 合成了壳聚糖负载的双组分催化剂CS-[emim]Br/ZnCl2用于CO2和环氧丙烷合成碳酸丙烯酯的过程。结果表明，在条件为[emim]Br与ZnCl2配比为6：1，反应温度为120 ℃，反应压力为1.5 MPa，时间为1.5 h时，该催化剂可以获得96%的碳酸丙烯酯收率；对于端位环氧化合物，该催化剂都表现出了很高的催化活性，相应环状碳酸酯收率均在86%以上。 3. 将[bmim]OH/[bmim]X (X=Cl, BF4, and PF6,)复合离子液体催化剂用于环状碳酸酯的水解过程，结果表明：[bmim]OH/[bmim]BF4复合离子液体对于本反应具有优良的催化活性，在[bmim]OH与[bmim]BF4配比为1：1，nEC/nH2O为1：1.45，反应温度为140 ℃，反应压力为0.4 MPa，时间为1.5 h的条件下，该催化剂可以获得94%的碳酸乙烯酯收率和100%的乙二醇选择性；经过5次循环，催化剂仍保持较高的催化活性。 4. 完成了催化剂规模化制备，并进行了模式试验研究；模式试验表明：（1）在近600 h运转过程中，环氧乙烷转化率接近100%，乙二醇总选择性为99%~99.5%，未观察到二乙二醇（DEG）的积累；（2）催化剂活性高、稳定性好，且对工业环氧乙烷具有优良适应性；（3）乙二醇产品质量超过了国家GB 4649-2008优等品指标。
英文摘要	Ethylene glycol (EG) is an important raw material in organic chemical industry. Catalytic hydrolyzation of ethylene carbonate (EC) to ethylene glycol is a route of high EG yield and selectivity, low water ratio and low energy consumption. High efficient catalysts of ionic liquids and renewable immobilized catalyst were designed and synthesized for the development of a new energy saving process of EG through hydrolysis of EC in this paper. The major work and innovative results for this dissertation are summarized as follows. 1. ZnBr2-based choline chloride ionic liquid was first examined for solvent-free synthesis of cyclic carbonate from carbon dioxide and epoxide under solventless condition, it is demonstrated ZnBr2 combined with biodegradable choline chloride is very efficient and selective. ZnBr2 and choline chloride showed a synergetic effect in promoting the reaction, and a plausible reaction mechanism has also been proposed. In addition, various reaction parameters on the catalytic performance were discussed in details. Moreover, the simple procedures are also expected to contribute to the development of more economical and environmentally benign pathway for efficient fixation of carbon dioxide. 2. A Chitosan-supported zinc chloride/[emim]Br has been proved to be an efficient heterogeneous catalyst for solventless synthesis of cyclic carbonates from epoxides and carbon dioxide under mild conditions, which requires no additional organic solvents either for the reaction or for the separation of product. As heterogeneous catalysts, it can be easily recovered by filtration and reused over seven times with slight loss of its catalytic activity, while the selectivity of the product remained more than 99%. Herein, reaction temperature, carbon dioxide pressure, reaction time and the molar ratio of zinc chloride to [emim]Br covalented to the catalyst were investigated. The optimum reaction conditions were 120 ℃, 1.5 MPa and 1.5 h. Importantly, this environmentally benign and cost-effective process has great potential to be applied in various fix-bed continuous flow reactors in industry. 3. [bmim]X/[bmim]OH (X=Cl, BF4, and PF6,) basic ionic liquids were developed and used for the hydrolysis of ethylene carbonate to ethylene glycol. Parameters, such as various ionic liquids, the molar ratio of [bmim]X to [bmim]OH, ionic liquid amount, the molar ratio of water to ethylene carbonate, reaction temperature, pressure and reaction time, were investigated in details. It was found that excellent yield (>93%) and more than 99% selectivity of ethylene glycol could be achieved in the presence of [bmim]BF4/[bmim]OH. Under the optimized reaction conditions, this catalyst could be reused at least up five times with slight loss of catalytic activity, while the selectivity of the ethylene glycol remains more than 99%. 4. Further investigations were carried out on the pilot plant synthesis of EG via EC hydrolysis by use of ionic liquid after catalyst large scale preparaed. 600 hrs continuous results showed that: (1) near a 100% ethylene oxide (EO) conversion with 99%~99.5% total product selectivity could be obtained, and no cumulation of diethlyene glycol (DEG) was detected; (2) catalyst was stable and high active even for industrial EO; and (3) high quality of EG was obtained beyond the national standard of GB 4649-2008.
公开日期	2013-09-17
页码	115
内容类型	学位论文
源URL	[http://ir.ipe.ac.cn/handle/122111/1515]
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	孟震英. 离子液体催化环状碳酸酯合成及其水解应用基础研究[D]. 北京. 中国科学院研究生院. 2010.

个性服务

查看访问统计

相关权益政策

暂无数据

收藏/分享

除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。