Anchored homogeneous catalysts: the role of the heteropoly acid anchoring agent

Augustine, Robert L.; Tanielyan, Setrak K.; Mahata, Nagendranath; Gao, Yujing; Zsigmond, Ágnes; Yang, Hong

doi:10.1016/s0926-860x(03)00389-2

Cited by 87 publications

(78 citation statements)

References 8 publications

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“…The supports used in this work were commercially available neutral gamma-alumina and alumina produced in a special process indicated later, namely, mesoporous Al 2 /g nitrogen (STP). It can be inferred from the structural parameters shown in Table 1 that the incorporation of organometallic complexes onto both PTA and Al 2 O 3 caused a decrease in mesopore size, surface area, and pore volume, obviously because of the coverage of pore surface with the organometallic complexes, leading to an increase in the original wall thickness and even partial blockage of the mesoporous channels [7].…”

Section: Immobilization and Characterization Of The Catalystmentioning

confidence: 99%

“…The performance of the catalyst seems to depend on the nature of support; higher activity and stability are observed with 2 ]BF 4 complex was immobilized on commercially available Al 2 O 3 and mesoporous Al 2 O 3 by means of PTA. In both cases, the incorporation of the PTA and the rhodium complex caused a decrease in the surface area, pore volume, and mesopore size of the support.…”

Section: Immobilization and Characterization Of The Catalystmentioning

confidence: 99%

“…From an industrial point of view, however, solid catalysts that are not soluble in the same phase as the organic reactant have the inherent advantage of easy separation and, very often, also of better handling properties. Augustine and coworkers investigated different heteropolyanions (HPAs) as anchoring agents [2]. They found that the nature of the HPA can influence both the activity and the selectivity of the reactions.…”

Section: Introductionmentioning

confidence: 99%

“…The [Rh(COD)((S)-MonoPhos) 2 ]BF 4 complex was successfully immobilized by Sheldon and coworkers on four different anionic carrier materials [3]: mesoporous aluminosilicate AlTUD-1, phosphotungstic acid (PTA) on alumina, Nafion, and Nafion silica composite [4]. The catalysts showed a virtually identical behavior to their homogeneous counterparts.…”

Section: Introductionmentioning

confidence: 99%

“…Here, we report our results on the asymmetric hydrogenation of a benchmark substrate, such as methyl acetamidoacrylate, using immobilized [Rh(COD)((S)-MonoPhos) 2 ] + catalyst in the flow reactor [5]. A detailed investigation of the effects of changes in the reaction conditions (temperature, pressure, solvent, support, concentration of substrate, flow rate) has been carried out.…”

Section: Introductionmentioning

confidence: 99%

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A Continuous-Flow System for Asymmetric Hydrogenation Using Supported Chiral Catalysts

Madarász¹,

Farkas²,

Balogh³

et al. 2011

J Flow Chem

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Highly active immobilized hydrogenation catalytic systems were used in the H-Cube ™ hydrogenation reactor. "In situ" produced [Rh(COD)((S)-MonoPhos) 2 ]BF 4 complex was immobilized on commercially available Al 2 O 3 and mesoporous Al 2 O 3 by means of phosphotungstic acid (PTA), respectively. The optimum reaction conditions were determined and studied at different temperature, pressure, and flow rate values. Furthermore, the effect of the substrate concentration, microstructure of the support, and the stability of the complex were investigated. A continuous-flow reaction system using a stationary-phase catalyst for the asymmetric hydrogenation of methyl acetamidoacrylate was developed and run continuously for 12 h with >99% conversion and 96-97% enantioselectivity.

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Section: Immobilization and Characterization Of The Catalystmentioning

confidence: 99%

Section: Immobilization and Characterization Of The Catalystmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A Continuous-Flow System for Asymmetric Hydrogenation Using Supported Chiral Catalysts

Madarász¹,

Farkas²,

Balogh³

et al. 2011

J Flow Chem

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Recyclable Stereoselective Catalysts

Monteiro¹,

Trindade²,

Góis

et al. 2011

Catalytic Methods in Asymmetric Synthesis

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Enantioselective Hydrogenation: Phospholane Ligands

Cobley¹,

Moran²

2006

The Handbook of Homogeneous Hydrogenation

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The ability to efficiently synthesize enantiomerically enriched materials is of key importance to the pharmaceutical, flavor and fragrance, animal health, agrochemicals, and functional materials industries [1]. An enantiomeric catalytic approach potentially offers a cost-effective and environmentally responsible solution, and the assessment of chiral technologies applied to date shows enantioselective hydrogenation to be one of the most industrially applicable [2]. This is not least due to the ability to systematically modify chiral ligands, within an appropriate catalyst system, to obtain the desired reactivity and selectivity. With respect to this, phosphorus(III)-based ligands have proven to be the most effective.Amongst the hundreds of chiral phosphorus-based ligands developed since the seminal studies of Knowles and Horner [3], only a select few ligand families have had a revolutionary impact on the field. The highly modular chiral C 2 -symmetric phospholane ligands (DuPhos TM and BPE), developed by Burk and coworkers at DuPont, are one such example. As a result, much effort has been directed towards building on this breakthrough discovery and extending both the design and application of this ligand class.In this chapter, we review the growing family of phospholane-based chiral ligands, and specifically examine their applications in the field of enantioselective hydrogenation. In general, this ligand class has found its broadest applicability in the reduction of prochiral olefins and, to a significantly lesser extent, ketones and imines; this is reflected in the composition of the chapter. Several analogous phosphacycle systems have also been included, where appropriate.Whilst trying to be comprehensive, we have also intended to introduce a strong applied flavor to this summary. In the industrial case, catalyst performance is critically judged on overall efficiency, namely catalyst productivity and activity as well as enantioselectivity. As a result, turnover numbers (TONs) and turnover frequencies (TOFs) have been included or calculated whenever possible and meaningful. 773The Handbook of Homogeneous Hydrogenation. Edited by J. G. de Vries and C. J. Elsevier

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Anchored homogeneous catalysts: the role of the heteropoly acid anchoring agent

Cited by 87 publications

References 8 publications

A Continuous-Flow System for Asymmetric Hydrogenation Using Supported Chiral Catalysts

A Continuous-Flow System for Asymmetric Hydrogenation Using Supported Chiral Catalysts

Recyclable Stereoselective Catalysts

Enantioselective Hydrogenation: Phospholane Ligands

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