离子液体催化制备环状碳酸酯的研究
文献类型：学位论文
| 作者 | 孙剑 |
| 学位类别 | 博士 |
| 答辩日期 | 2009-06-02 |
| 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 | 张锁江 |
| 关键词 | 离子液体 催化 CO2固定 环状碳酸酯 乙二醇 |
| 其他题名 | Study on the Synthesis of Cyclic Carbonates Catalyzed by Ionic Liquids |
| 学位专业 | 应用化学 |
| 中文摘要 | 作为新兴绿色介质，离子液体所具备的结构可设计、热稳定性好等优良性质，使其广泛应用于催化反应、有机合成、分离过程和电化学等领域。开发新型离子液体和拓展离子液体新的应用始终是离子液体研究的主要方向。针对CO2和环氧化合物反应制备环状碳酸酯过程中出现的催化剂活性低、反应条件苛刻、需附加有机溶剂等关键性问题，本论文开展了离子液体催化合成环状碳酸酯反应过程的研究，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. 开发了用于制备环状碳酸酯的氯化锌/季鏻盐([PR1R2R3R4]+X−; X= Cl, Br, I)二元催化体系。结果表明，在无溶剂的温和反应条件下(1.5 MPa, 120 ℃, 1 h)，ZnCl2/PPh3C6H13Br(摩尔比为l:6)可以实现96.0%的环氧丙烷转化率和＞99.5%的碳酸丙烯酯选择性，活性高于现有ZnCl2与其他常规离子液体组成的催化体系；催化剂循环使用十次后活性不变；该催化体系同样适用于其他端位环氧化合物。 2. 研究了在含水条件下离子液体催化合成环状碳酸酯的反应过程。研究发现：含水条件下环状碳酸酯的合成速率比无水条件下的速率可以高出5-6倍；通过调节反应体系中水量，可以获得高达97%的产品收率和97%的选择性；除水之外，含羟基的溶剂同样可以促进反应；基于实验结果提出羟基利用氢键诱导开环协同催化机理。在此基础上重点开展含水条件下离子液体催化碳酸乙烯酯法制备乙二醇的应用研究，开发了相应的离子液体催化剂，完成催化剂公斤级放大制备，随后在小试基础上成功开展了模式放大试验，阶段结果表明：在260小时的长运转过程中，催化剂性能稳定，环加成反应环氧乙烷平均转化率为99.3%，碳酸乙烯酯和乙二醇平均总选择性为99.6%；水解反应碳酸乙烯酯转化率为100%，乙二醇选择性＞99%。 3. 设计合成了醇羟基修饰的功能化离子液体催化剂用于环状碳酸酯的合成，结果表明：合成的三种羟基离子液体活性都明显高于相应的常规离子液体；该结果进一步验证了所提出的催化反应机理。其次为解决催化剂分离问题，分别开发了MCM–41分子筛和树脂化学负载的羟基功能化离子液体催化剂，并用于合成环状碳酸酯，实验证明：基于羟基的协同催化作用，在优于现有异相催化剂所使用的反应条件下，所开发的催化剂都能够高效、稳定地催化反应。最后为了进一步研究羧羟基对催化剂活性的影响，合成了阳离子上单羧基和双羧基修饰的酸性功能化离子液体催化剂用于合成环状碳酸酯，研究发现：增加羧基个数或者增加羧基链长度有助于提高Brønsted酸性离子液体的催化活性及产品选择性。 |
| 英文摘要 | As novel green media, ionic liquids (ILs) have been applied to catalysis, organic synthesis, separation, electrochemistry, and so on, due to their thermal stability and widely tunable properties. Synthesizing new kinds of ILs and exploiting ILs’ new applications are always the main tasks of ILs’ studies. Considering the key problems in cycloaddition of CO2 to epoxide to produce cyclic carbonate, the synthesis of cyclic carbonate using various IL catalysts has been systematically investigated, and further applied to the synthesis of ethylene glycol (EG) via ethylene carbonate (EC). The investigations could provide some valuable fundamental data for CO2 conversion as well as the industrial application of ILs. The major work and innovative results for this dissertation are summarized as follows. 1. An efficient Lewis acid/base catalytic system composed of ZnCl2 and traditional phosphonium halide ([PR1R2R3R4]+X−, X=Cl, Br, I) was developed and showed high activity and selectivity for the coupling reaction of CO2 and epoxide under the mild conditions. It was found that a 96.0% conversion of propylene oxide as well as ＞99.5% propylene carbonate yield could be achieved in the presence of ZnCl2/PPh3C6H13Br (molar ratio=l:6) at 1.5 MPa, 120 ℃ without any organic solvents, which was higher than those with other similar reported catalysts. The catalyst could be reused without loss of catalytic activity after ten times, and was proved to be applicable to other terminal epoxides. 2. A process for the synthesis of cyclic carbonate in the presence of water with ionic liquid was studied, and it was found that: (1) the reaction ratio could be about 5-6 times higher in the presence than that in the absence of water; (2) by tuning the amount of water, cycloaddition of CO2 to epoxide in aqueous medium leaded to cyclic carbonates with excellent yields (97%) and high selectivities (97%); (3) hydroxyl group containing solvent could also accelerate the reaction. Based on the above results, a synergic catalytic mechanism of hydroxyl group using hydrogen bonding as an inducement of epoxy ring-opening was proposed. Then, further investigations were carried out on the synthesis of EG via EC by use of ionic liquid including catalyst development and its large scale preparation, reaction conditions optimization, and the investigation on the pilot plant. 260 hrs continuous results showed that: (1) the activity of catalyst was stable; (2) 99.3% ethylene oxide (EO) conversion with 99.6% total selectivity of EC and EG could be obtained in cycloaddition of CO2 to EO; and (3) 100% EC conversion and ＞99% EG selectivity were realized. 3. A series of alcoholic hydroxyl-functionalized ILs (HFILs) were synthesized and applied to the synthesis of cyclic carbonate. They showed more efficient activities in the coupling of epoxide and CO2 than the traditional ILs, which further proved the mechanism proposed. The catalytic efficiency in cyclic carbonate synthesis with HFILs, which were supported on polymer and MCM-41 molecule sieve, demonstrated that the synergic catalytic fuction of hydroxyl group made these heterogeneous catalysts be more active than other supported traditional ionic liquid catalysts under the same conditions. To further investigate the effect of carboxylic hydroxyl group on the reaction, ionic liquids functionalized with one or two carboxylic acidic groups in cations were synthesized and applied. It was demonstrated that the activity of Brønsted acid ionic liquid and the selectivity of product all increased with the increasing of carboxylic hydroxyl group number or length. |
| 语种 | 中文 |
| 公开日期 | 2013-09-13 |
| 页码 | 197 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1258]  |
| 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 | 孙剑. 离子液体催化制备环状碳酸酯的研究[D]. 过程工程研究所. 中国科学院过程工程研究所. 2009. |
入库方式： OAI收割
来源：过程工程研究所
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