Immobilization of Homogeneous Catalysts: Supported Aqueous Phases, Ion Exchange Resins, and Membranes

均相催化剂的有效固定化对石油化工和精细化学工业具有重要的技术意义。这项工作涉及催化剂固定化技术，既适用于大规模生产，也适用于小规模生产。负载型水相(SAP)催化剂的使用已被证明对多种烯烃的氢甲酰化反应是有效的。本工作用物理化学方法考察了SAP催化剂的独特性质，特别是水在催化活性测定中的作用。SAP的概念也扩展到催化氧化。此外，还探索了其他固定化技术，包括离子交换树脂作为具有官能化配体的催化剂固定化的手段，以及使用非常大但可溶的配体与膜分离技术相结合的方法。众所周知，许多均相(可溶)催化剂在温和的条件下可以高选择性地促进化学转化，但由于从含有催化剂的溶液中分离产品的高昂成本以及催化剂的重复使用往往是困难的(如果不是不可能的话)，阻碍了它们的商业使用。通过使均相催化剂表现得更像多相催化剂，固定化技术提供了绕过这些问题的前景。事实证明，在保持理想的催化性能的同时实现这一点是困难的，但潜在的新工艺的好处将是巨大的。

Effective immobilization of homogeneous catalysts is technologically important for the petrochemical and fine- chemical industries. This work addresses techniques for catalyst immobilization that are applicable both to large- scale and to small-scale production. The use of supported aqueous-phase (SAP) catalysts has already been shown to be effective for hydroformylation of a variety of olefins. The present work examines the unique properties of SAP catalysts using physicochemical approaches, in particular the role of water in the determination of catalytic activity. The SAP concept is also extended to catalytic oxidations. Additionally, other immobilization techniques are explored, including ion-exchange resins as a means to immobilize catalysts with functionalized ligands, and the use of very large, but soluble, ligands combined with membrane separation technology. Many homogeneous (soluble) catalysts are known to facilitate chemical transformations with high selectivity under mild conditions, but their commercial use is inhibited by the high cost of separating the products from the solution containing the catalyst and the fact that reusing the catalyst is often difficult if not impossible. Immobilization techniques offer the prospect of circumventing these problems by making the homogeneous catalysts behave more like heterogeneous catalysts. Accomplishing this while preserving the desirable catalytic properties has proven to be difficult, but the benefit in potential new processes would be enormous.