Heterogenization of homogeneous catalyst

Recovery ofthe soluble cattalysts presents the greatest difficulty in large scale appfications of homogeneous catalysis. In a way, aqueous biphasic catalysis itself provides a solution of this problem. It is not the aim of this book to discuss the various other methods of heterogenization of homogeneous catalysts. The only exception is the use of water-soluble... 

For this work, three types of mesoporous materials are the choice for the heterogenization of homogeneous catalysts Al-MCM-41, Al-MCM-48, and... 

Much work is still dedicated to reducing catalyst consumption and waste. Immobilization (or the heterogenization of homogeneous catalysts) is one of the approaches but may result in a loss of activity and/or selectivity and a high sensitivity to impurities. 

Supported aqueous-phase catalysis (SAPCs) offer a second relevant possibility for heterogenization of homogeneous catalysts [132, 133]. Initially, water was used as the hydrophilic liquid and these catalysts are therefore denoted as SAPCs [134]. 

Chapter 6 provides an extensive review of the uses of carbon as a catalyst, with particnlar emphasis being placed on cases in which active sites have been properly identified and activity correlations established. The special case of nitrogen-doped carbons and their catalytic activity in oxidation reactions is discussed in Chapter 7, and Chapter 8 covers the heterogenization of homogeneous catalysts by anchoring transition-metal complexes onto the snrface of suitable carbon materials. 

A considerable effort has been expended in the heterogenization of homogeneous catalysts. A particular benefit would be that facile catalyst/product separation could be achieved which could have commercial significance in the hydroformylation of high boiling point or thermally unstable alkenes. At the same time it is desirable that these catalysts have similar activities and equivalent or better selectivities than their homogeneous counterparts. While diffusion presents a drawback with respect to activity it may be... 

Finally, at a research level, heterogenizations of homogeneous catalysts have been extensively studied. The motivation behind this method is to combine the advantages of heterogeneous and homogeneous catalysts, i.e., easy separation with high selectivity. Basically, in this method... 

Figure 5.8 Schematic representation of the three modes for heterogenization of homogeneous catalyst by assembling chiral bridging ligands with metallic ions.

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