Heterogeneous hybrid catalyst

Multicomponent Reactions Concepts and Applications for Design and Synthesis, First Edition. Edited by Raquel R Herrera and Eugenia Marquds-L6pez. 2015 John Wiley Sons, Inc. Published 2015 by John Wiley Sons, Inc. 

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K. Arya, U. C. Rajesh, D. S. Rawat, Green Chem. 2012, 14, 3344—3351. Proline confined FAU zeolite heterogeneous hybrid catalyst for the synthesis of spiroheterocycles via a Mannich type reaction. 

A networked supramolecular POM-based hybrid catalyst has been synthesized by Ikegami and coworkers via the self-assembly of [PWi2O40]3 and non-crosslinked copolymer based on N-isopropylacrylamide (NIPAM) and ammonium cations (Figure 6.7) [124, 125]. This heterogeneous NIPAM-POM hybrid catalyst showed very high catalytic activity for the epoxidation of allylic alcohols with H202 (e.g., up to 35 000 TON for phytol). In addition, the oxygenation of amines and sulfide could be... 

The polysiloxane - SiOz hybrids were tested for their capability for heterogenizing homogeneous catalysts. The platinum(II) complex was obtained by replacement of ligands in the parent metal complex PtCl2(PhCN)2 by Vi groups. 

An important research area of catalysis is the heterogenization of metal complexes showing excellent activity and selectivity in the homogeneous phase (hybrid catalysts) [1]. The main advantage of supported metal complexes over unsupported ones is the ease of separation from the reaction media, which makes them economically convenient [2]. On the other hand, the main problems related with the heterogenization on solid supports are metal complex leaching and decrease in catalytic activity. 

However, some other aspects of the chemistry of ti bonded metal BT and DBT complexes could be of importance in connection with HDS. It is now known, for instance, that 4-methyl- and 4,6-dimethyldibenzothiophene are desulfurized mainly through prior hydrogenation of one or both of the arene rings [46, 112-115], and therefore the study of model ti -DBT complexes could be of use in developing efficient homogeneous, heterogeneous or hybrid catalysts for reducing the arene moieties in this type of molecule either as a pretreatment for conventional HDS, or as an added functionality in novel multimetallic catalyst formulations this possibility is further discussed in Chapter 3. 

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