Metathesis under Biphasic Conditions Using Monolithic-Supported Ionic Liquids

使用整体支撑离子液体在双相条件下进行复分解

• 批准号: 136355964
• 负责人: Professor Dr. Michael R. Buchmeiser
• 金额: --
• 依托单位: Lehrstuhl für Makromolekulare Stoffe und Faserchemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/136355964?language=en
• 关键词: Metathesis; under; Biphasic; Conditions; Using

Polymeric monolithic supports shall be prepared either via ring-opening metathesis polymerization (ROMP) or via electron beam (EB) triggered free radical polymerization. The resulting porous monolithic structures shall serve as support materials for Ionic liquids (ILs) in which a series of novel metathesis catalysts bearing ionic moieties shall be dissolved. Metathesis reactions shall be run under biphasic conditions using a second organic phase immiscible with the IL. For these purposes, novel persistent, IL-soluble Schrock and Grubbs-Hoveyda-type catalysts with pendant ionic groups are to be synthesized. The monoliths shall be subject to in situ surface functionalization using ionic monomers based on quaternary ammonium, imidazolium and phosphonium salts as well as with 2-propoxystyryl ethers. In the case of ROMP-derived monoliths, this is to be accomplished by the use of the corresponding norborn-2-ene or cyclooctene derivatives. In the case of EB-triggered free radical polymerization-derived monoliths, acrylates containing quaternary ammonium, imidazolium and phosphonium salts as well as 2-propoxystyryl ethers are to be surface-grafted via post-synthesis, EB-triggered free radical polymerization. Alternatively, a ROMP-based protocol using the above-mentioned norborn-2-ene or cyclooctene derivatives shall be applied. The thus prepared surface-functionalized monoliths shall then be treated with appropriate amounts of ionic liquids (ILs) based on a similar structural motif as used for surface grafting (i.e. for the corresponding quaternaized N- and P-based monomers). Special care shall be devoted to compatibility issues, which are mainly related to both the nature of the grafted molecules and the ILs and to the grafting density as well as of the degree of polymerization of the graft polymers based on the quaternary ammonium, imidazolium and phosphonium salts, respectively. In all cases, the final functionalized monoliths shall be characterized by micro- and mesopores. Apart from ionic interactions between the graft polymers and the ILs, these pores allow for retaining the ionic liquids (ILs) at the surface by capillary forces. In addition, sufficient interconnected pores in the μm-range shall be present and guarantee for a fast flow-through. An optimization in terms of grafting density, chain length of the graft polymers, nature of the functional monomer and IL as well as optimum layer thickness of the IL shall be carried out, thus offering optimum catalytic performance while resulting in a minimum leaching. The ultimate goal is the realization of novel ionic metathesis catalysts, their immobilization within monolith-supported ILs, and the use of the thus prepared supported catalysts in continuous metathesis reactions including ring-closing metathesis (RCM), ring-opening cross metathesis (ROC), cross-metathesis and ene-yne cross metathesis reactions under biphasic conditions. The thus created immobilized systems shall provide further insight into the reactivity of both Schrock- and Grubbs-Hoveyda-type catalysts in metathesis reactions within ILs. Even more important, the supported catalysts to be developed here shall help to solve the problems of support-regeneration and recharging, metal contamination of products and catalyst longevity.

聚合物整体载体应通过开环复分解聚合（ROMP）或电子束（EB）引发的自由基聚合制备，所得多孔整体结构应作为离子液体（IL）的载体材料，其中一系列新颖的材料。带有离子部分的复分解催化剂应在双相条件下使用与离子液体不混溶的第二有机相进行溶解。具有侧离子基团的 Schrock 和 Grubbs-Hoveyda 型催化剂应使用基于季铵、咪唑鎓和鏻盐以及 2-丙氧基苯乙烯基醚的离子单体进行原位表面官能化。对于 ROMP 衍生的整体材料，这将通过使用相应的降冰片-2-烯或对于由 EB 引发的自由基聚合衍生的整体材料，含有季铵盐、咪唑鎓盐和鏻盐以及 2-丙氧基苯乙烯基醚的丙烯酸酯将通过后合成、EB 引发的自由基聚合进行表面接枝。或者，使用上述的norborn-2-ene的基于ROMP的协议。然后，应使用基于与表面接枝相似的结构基序（即相应的季铵化 N 基和 P 基）的离子液体（IL）处理如此制备的表面官能化整体材料。应特别注意相容性问题，这主要与接枝分子和离子液体的性质以及接枝密度和接枝聚合度有关。分别基于季铵盐、咪唑盐和鏻盐的聚合物 在所有情况下，最终的功能化整料应具有微孔和中孔的特征，除了接枝聚合物和离子液体之间的离子相互作用外，这些孔还可以保留离子。此外，应存在足够的微米范围内的互连孔，并保证快速流通。应根据接枝密度、接枝聚合物的链长、功能单体和离子液体的性质以及离子液体的最佳层厚度进行优化，从而提供最佳的催化性能，同时实现最小的浸出。目标是实现新型离子复分解催化剂，将其固定在整体负载的离子液体中，以及将由此制备的负载催化剂用于连续复分解反应，包括闭环复分解（RCM）、双相条件下的开环交叉复分解（ROC）、交叉复分解和烯-炔交叉复分解反应由此创建的固定化系统将进一步了解Schrock型和Grubbs-Hoveyda型催化剂在复分解中的反应性。更重要的是，这里开发的负载型催化剂将有助于解决载体再生和再充电、产品的金属污染和催化剂寿命的问题。