第二层配位空间效应在开环聚合及烯烃聚合中的应用

发布时间：2018-04-27 22:26

本文选题：膦磺酸钯 + 镍催化剂　；参考：《中国科学技术大学》2017年硕士论文

【摘要】：聚酯与聚烯烃是两类应用极其广泛的聚合物,其生产工艺的改进、聚合物性能的提高均具有十分重要的意义与价值。多年来,众多科研工作者投入到研发新型聚合反应催化剂的工作中,在学术界与工业界均有所突破。自齐格勒-纳塔催化剂问世以来,通过对催化剂的调节来改进烯烃聚合反应的活性以及聚合物的性能已获得了极大成功。然而,在烯烃与极性单体的共聚反应中,极性单体中的部分官能团对催化剂的毒化作用始终限制着绝大多数催化剂的实际应用前景。研发拥有高官能团容忍度的新型催化剂成为了我们工作的重点。在本篇论文中,我们通过对催化剂配体进行修饰,引入第二层配位空间,以达到在极性单体存在情况下稳定催化剂活性中心的作用,借此改进开环聚合以及烯烃与极性单体共聚的性能。1.首先,我们合成并表征了一系列含有吡咯亚胺配体的铝配合物,并对其催化己内酯开环聚合的反应性能进行了分析。这些配合物的配体上含有由氧、硫等杂原子取代的官能团边臂。这些杂原子的引入,形成了第二层配位空间,它们可以在很大程度上提高配合物的催化活性。在实际催化反应中,当加入苄醇作为引发剂时,这些配合物可以可控且高效地催化己内酯的开环聚合;在没有苄醇等引发剂存在的条件下,它们依旧保持着高活性和可控性。2.其次,我们合成并表征了一系列含有不同长度烷氧链取代基的膦磺酸钯、镍配合物,并对其催化烯烃聚合的反应性能进行了分析。催化剂配体取代基上的聚乙二醇单元与金属中心或极性单体的相互作用可以调节乙烯聚合和共聚过程。在乙烯聚合中,该策略导致活性提高、催化剂稳定性提高和聚乙烯分子量增大。在乙烯与极性单体共聚反应中,可以实现多种共聚参数的改进(包括单体插入比、共聚物熔点等)。对于具有氢键供体能力的极性单体,这种效果最为显着。
[Abstract]:Polyester and polyolefin are two kinds of polymers which are widely used. It is of great significance and value to improve the production process and properties of polymers. For many years, many researchers have devoted themselves to the research and development of new polymerization catalysts, and have made breakthroughs in both academia and industry. Since Ziegler-Natta catalyst came into being, the activity of olefin polymerization and the performance of polymer have been greatly improved by adjusting the catalyst. However, in the copolymerization of olefins and polar monomers, the toxicity of some functional groups in polar monomers has always restricted the practical application prospects of most of the catalysts. Research and development of new catalysts with high functional group tolerance has become the focus of our work. In this paper, we modify the catalyst ligands and introduce the second coordination space to stabilize the active centers in the presence of polar monomers. In order to improve the ring-opening polymerization and olefin and polar monomer copolymerization properties. 1. Firstly, a series of aluminum complexes containing pyrrolidine ligands were synthesized and characterized, and their catalytic properties for ring-opening polymerization of caprolactone were analyzed. The ligands of these complexes contain functional arm which is replaced by oxygen, sulfur and other heteratomic atoms. The introduction of these heteroatoms forms a second coordination space, which can improve the catalytic activity of the complexes to a great extent. In the actual catalytic reaction, when benzyl alcohol is added as initiator, these complexes can catalyze the ring-opening polymerization of caprolactone in a controllable and efficient manner, and they still maintain high activity and controllability in the absence of benzyl alcohol and other initiators. Secondly, a series of palladium and nickel phosphine sulfonate complexes with different alkoxy chain substituents were synthesized and characterized, and their catalytic properties of olefin polymerization were analyzed. The polymerization and copolymerization of ethylene can be regulated by the interaction of polyethylene glycol units with metal centers or polar monomers on the catalyst ligand substituents. In ethylene polymerization, this strategy leads to higher activity, higher catalyst stability and higher molecular weight of polyethylene. In the copolymerization of ethylene with polar monomers, a variety of copolymerization parameters (such as monomer insertion ratio, copolymer melting point, etc.) can be improved. This effect is most remarkable for polar monomers with hydrogen bond donor ability.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O641.4;O631.5

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