Palladium complexes of phosphine functionalised carbosilane dendrimers as catalysts in a continuous flow membrane reactor†

Groot, Debby de; Eggeling, Eva B.; Wilde, Janine C. de; Kooijman, Huub; Haaren, Richard J. van; Made, A.W. van der; Spek, A. L.; Vogt, Dieter; Reek, Joost N. H.; Kamer, Paul C. J.; Leeuwen, Piet W. N. M. van

doi:10.1039/a904455h

Cited by 106 publications

(54 citation statements)

References 21 publications

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“…27 In batch processes, the activity per palladium center of different generations Pd(allyl) dendrimer complexes was constant, indicating that all active sites act as independent catalysts. Under continuous reaction conditions, however, using the largest dendrimer (9) (Scheme 9, R > 0.981), an unexpected rapid decrease in activity was found that could not solely be ascribed to washout of the homogeneous catalyst.…”

Section: Polymer-enlarged Homogeneous Catalystsmentioning

confidence: 97%

The Use of Ultra- and Nanofiltration Techniques in Homogeneous Catalyst Recycling

2002

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In recent years, the application of membrane technology in homogeneous catalyst recycling has received widespread attention. This technology offers a solution for the major drawback of homogeneous catalysis, that is, recycling of the catalyst. From both an environmental and an industrial point of view, this technology is very interesting, since it allows the future application of homogeneous catalysts in the synthesis of commercial products, leading to faster, cleaner and highly selective green industrial processes. In this Account, an overview is given of the promising results obtained in the field of homogeneous catalyst recycling using nanofiltration membrane technology.

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Section: Polymer-enlarged Homogeneous Catalystsmentioning

confidence: 97%

The Use of Ultra- and Nanofiltration Techniques in Homogeneous Catalyst Recycling

2002

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“…[10,59] However, to obtain detailed information about the processes in the reactor vessel and to calculate the expected conversions at a given residence time, [60] the kinetics of the reaction have to be known. As a matter of fact, these data have not been determined before for the system we are using.…”

Section: Kinetic Investigations Of the Palladium-catalyzed Allylic Ammentioning

confidence: 99%

“…The formation of soluble inactive species is expected because no formation of palladium black was observed, which otherwise is often the case in palladium-catalyzed reactions. [59,81,82] A second continuous catalysis experiment was performed using the same conditions to exclude possible errors in the first catalytic run. Furthermore, the membrane was first treated with trimethyl orthoformate to remove traces of water and alter the surface of the membrane, according to Eggeling et al [83] A significant increase in total turnover number was observed in the hydrovinylation reaction compared to nontreated membranes.…”

Section: Continuous Allylic Alkylation Reactionsmentioning

confidence: 99%

Molecular‐Weight‐Enlarged Multiple‐Pincer Ligands: Synthesis and Application in Palladium‐Catalyzed Allylic Substitution Reactions

et al. 2009

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Three different pincer ligand systems are synthesized via nucleophilic substitution reactions of polyaromatic benzyl bromides as support molecules and phenol derivatives as ligand precursors. Retention tests using a polymeric nanofiltration membrane show moderate to good retention in THF and CH(2)Cl(2). Concentration-dependent NMR spectroscopy gives no indication for the formation of aggregates in solution. The three ligand systems are active in both the allylic alkylation and allylic amination reactions and show high selectivity towards the linear trans products. An investigation of the kinetic parameters of the allylic amination reaction show that the reaction of cinnamyl acetate with morpholine is of zero order in cinnamyl acetate and of first order in morpholine. The order in catalyst is found to be one, and the rate constant k' is determined for a reaction under standard conditions. Moreover, one of the tri(pincer)-palladium complexes is used as soluble, molecular-weight-enlarged homogeneous catalyst in continuous allylic alkylation and amination reactions. The conversion of the allylic alkylation reaches a maximum of 30 %, while a maximum conversion of 80 % is reached in the allylic amination reaction. No palladium black was formed.

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“…These results suggest that the catalyst decomposes during the course of the reaction and leaches through the membrane as small soluble metal clusters. [28,29] The leaching gives rise to two problems, loss of expensive catalyst or active metal and contamination of the product with this metal. In some cases it can Eur.…”

Section: The Corresponding Pd Complexes (6) Were Used For the Pd-catamentioning

confidence: 99%

Continuous Homogeneous Catalysis

2005

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This review article illustrates possible aspects for molecularweight enlargement and immobilisation of transition-metal complexes that have been developed for bridging the gap between homogeneous and heterogeneous catalysis. The recycling of homogeneous catalysts can be performed using different types of supports, such as dendrimers, hyperbranched polymers, nanostructured materials or stabilized nanoparticles in combination with suitable filtration methods

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Palladium complexes of phosphine functionalised carbosilane dendrimers as catalysts in a continuous flow membrane reactor†

Abstract: Phosphine functionalised carbosilane dendrimers have been synthesised and their palladium complexes used as catalysts in the allylic alkylation reaction performed in a continuous flow membrane reactor.

Cited by 106 publications

References 21 publications

The Use of Ultra- and Nanofiltration Techniques in Homogeneous Catalyst Recycling

The Use of Ultra- and Nanofiltration Techniques in Homogeneous Catalyst Recycling

Molecular‐Weight‐Enlarged Multiple‐Pincer Ligands: Synthesis and Application in Palladium‐Catalyzed Allylic Substitution Reactions

Continuous Homogeneous Catalysis

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