Crossing the Borders Between Homogeneous and Heterogeneous Catalysis: Developing Recoverable and Reusable Catalytic Systems

• Published in: Topics in catalysis Vol. 48; no. 1-4; pp. 8 - 31
• Main Authors: Corma, Avelino, Garcia, Hermenegildo
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.05.2008
• Subjects: Catalysis; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Industrial Chemistry/Chemical Engineering; Original Paper; Pharmacy; Physical Chemistry; Covalently anchored chiral salen complexes; Carbapalladacycle as C–C catalyst; Ionic liquids in catalysis; Polyethylenglycol as scaffold; Single wall carbon nanotubes as supports in catalysis; Cooperative effect between support and anchored catalyst
• ISSN: 1022-5528; 1572-9028
• DOI: 10.1007/s11244-008-9056-5

Homogeneous and heterogeneous catalysis have developed independently as two separate disciplines. Homogeneous catalysis is characterized by the use of highly active, well-characterized compounds. In contrast, heterogeneous catalysis exhibits the advantage of easy separation of the catalyst from the products and can be easily adapted to continuous flow processes. In recent years, there is an emerging trend in catalysis that is bridging these two fields. On one hand, some of the complexes used in homogeneous catalysis are really precursors of nanoparticles that are species that have been traditionally subject of study in heterogeneous catalysis. On the other hand, the use of novel media allows the recovery and reuse of homogeneous catalysts, a hallmark of heterogeneous catalysis. Also, powerful experimental techniques can characterize the active sites in solids up to a much higher level of detail. In this review, we have selected two reaction types that are attracting much current interest, namely the enantioselective addition to aldehydes by chiral metallosalen complexes and the palladium catalyzed C–C cross coupling, and used them to illustrate a series of strategies based on new concepts that can serve to impart the advantages of homogeneous catalysis into heterogeneous catalysis and vice versa.