Metathesis under Biphasic Conditions Using Monolithic-Supported Ionic Liquids

聚合物整体载体应通过开环易位聚合（ROMP）或通过电子束（EB）触发的自由基聚合来制备。所得到的多孔整体结构将作为离子液体（IL）的载体材料，其中一系列新颖的易位催化剂轴承离子部分应溶解。复分解反应应在双相条件下使用与IL不混溶的第二有机相进行。为了这些目的，新的持久性，IL-可溶性Schrock和Grubbs-Hoveyda型催化剂与侧离子基团的合成。应使用基于季铵盐、咪唑鎓盐和鏻盐以及2-丙氧基苯乙烯基醚的离子单体对整料进行原位表面官能化。在ROMP衍生的整料的情况下，这通过使用相应的降冰片-2-烯或环辛烯衍生物来实现。在EB触发的自由基聚合衍生的整料的情况下，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合成后EB触发的自由基聚合进行表面接枝。或者，应应用使用上述降冰片-2-烯或环辛烯衍生物的基于ROMP的方案。然后将由此制备的表面官能化的整料用适量的离子液体（IL）处理，所述离子液体基于与用于表面接枝（即用于相应的季铵化的基于N和P的单体）的类似的结构基序。应特别注意相容性问题，其主要涉及接枝分子和IL的性质以及接枝密度以及分别基于季铵盐、咪唑鎓盐和鏻盐的接枝聚合物的聚合度。在所有情况下，最终官能化整料的特征在于微孔和中孔。除了接枝聚合物和离子液体之间的离子相互作用之外，这些孔允许通过毛细管力将离子液体（离子液体）保留在表面。此外，应存在足够的μ m范围内的互连孔，并保证快速流通。应在接枝密度、接枝聚合物的链长、功能单体和IL的性质以及IL的最佳层厚度方面进行优化，从而提供最佳的催化性能，同时导致最小的浸出。最终目标是实现新型离子复分解催化剂，将其固定在整料负载的离子液体中，以及将由此制备的负载型催化剂用于连续复分解反应，包括在两相条件下的闭环复分解（RCM）、开环交叉复分解（ROC）、交叉复分解和烯-炔交叉复分解反应。由此产生的固定化系统将提供进一步的洞察到Schrock和Grubbs-Hoveyda型催化剂在离子液体内的复分解反应的反应性。更重要的是，本文所开发的负载型催化剂将有助于解决载体再生和再装填、产物的金属污染和催化剂寿命等问题。

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.