Isomerization of 1-pentene catalyzed by Wilkinson's catalyst coordinatively bound to silica

Čapka, M.; Hetflejš, J.; Vdovin, V. M.; Федоров, В. Е.; Pritula, N. A.; Fedorova, G. K.

doi:10.1007/bf02062509

Cited by 5 publications

(3 citation statements)

References 8 publications

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“…Further evidence for this assumption is based on the selectivity of the hydrogenation reaction. It is known that heterogeneous catalysts that consist of metal particles can shift double bonds in linear 1‐alkenes,39a as well as cyclic olefins 39b. This double bond shift only takes place in the presence of H 2 .…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Immobilization, MAS and HR‐MAS NMR of a New Chelate Phosphine Linker System, and Catalysis by Rhodium Adducts Thereof

2011

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Section: Resultsmentioning

confidence: 99%

Synthesis, Immobilization, MAS and HR‐MAS NMR of a New Chelate Phosphine Linker System, and Catalysis by Rhodium Adducts Thereof

2011

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“…The previous immobilization attempts depended mostly on the formation of Rh–P coordination bonds between the metal (Rh) in the catalyst and the phosphine immobilizing groups which are grafted on the surface of solid supports such as silica nanoparticles or polystyrene, ,,,− and in fewer cases on immobilizing the Rh metal center in Wilkinson’s catalyst via the aliphatic amino groups of amine-functionalized silica forming Rh–N coordination bonds. , …”

Section: Introductionmentioning

confidence: 99%

A Novel Wilkinson’s Type Silica Supported Polymer Catalyst: Insights from Solid-State NMR and Hyperpolarization Techniques

et al. 2021

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The synthesis of a novel immobilized Wilkinson’s catalyst [SiO2∼PvPy-Wilk] is presented. The support material of this catalyst consists of silica particles that are modified with polymer brushes carrying pyridyl moieties that enable the coordination of Wilkinson’s catalyst. The synthesis of this catalyst is monitored by 1D and 2D multinuclear solid-state NMR techniques to confirm the success of the immobilization. The [SiO2∼PvPy-Wilk] catalyst is then tested in the hydrogenation of styrene, and its reusability is inspected showing that significant structural changes after several reaction cycles yield an activation of the catalyst. Finally, the catalyst is tested in PHIP experiments giving rise to about 200-fold enhancement of the signals of the hydrogenation product ethylbenzene.

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“…Later methods used to immobilize the Wilkinson catalyst include the preparation of a ROMPgel containing the triphenylphosphine moiety and attachment of an alkyldiphenylphosphine ligand onto oxide supports using siloxane “tethers”. − More direct approaches used the adsorption of the complex onto mesopourous SBA-15, intercalation in clays , or, even, incipient wetness adsorption on alumina or carbon. , Most of this work involved the use of low substrate to catalyst ratios (turnover numbers, TONs) for catalytic hydrogenations along with little or no information concerning the possible loss of rhodium during the reaction nor any comparison with the homogeneous 1 .…”

Section: Introductionmentioning

confidence: 99%

Anchored Wilkinson Catalyst

et al. 2011

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A series of Anchored Wilkinson’s Catalysts were prepared by the reaction of the homogeneous Wilkinson catalyst with alumina/heteropoly acid support materials. It was found that the catalytically active species from these materials were unique in that they had only a single triphenylphosphine and a heteropoly acid as ligands giving these catalysts distinctive steric and electronic characteristics. These catalysts were used to promote the hydrogenation of 1-hexene and limonene with substrate to catalyst ratios of 10,000 and 7,500 respectively. The results were compared with those obtained using the homogeneous Wilkinson and 1% Rh/Al2O3 catalysts with respect to catalyst activity and stability as well as the reaction selectivity as measured by the amount of double bond isomerization observed. The observed rates of hydrogen uptake and double bond isomer formation in the hydrogenations of both 1-hexene and limonene follow the same order with respect to the nature of the heteropoly acid ligand used to anchor the Wilkinson catalyst to the alumina: silicotungstic acid > phosphotungstic acid > phosphomolybdic acid > silicomolybdic acid for hydrogen addition and the reverse for isomerization. This consistency provides a measure of the electronic character of these Keggin heteropoly acids when acting as ligands. In contrast to the reactions observed with the anchored catalysts the homogeneous Wilkinson catalyst was incapable of completing these high substrate/catalyst ratio hydrogenations. It became deactivated at about 85% 1-hexene conversion and only 10% limonene hydrogenation. As compared with the anchored catalysts the supported Rh promoted more isomerization of 1-hexene and limonene while the hydrogenation of the trisubstituted double bond in p-menthene was more difficult over the supported metal catalyst than with the sterically more accessible anchored Wilkinson catalysts.

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Isomerization of 1-pentene catalyzed by Wilkinson's catalyst coordinatively bound to silica

Cited by 5 publications

References 8 publications

Synthesis, Immobilization, MAS and HR‐MAS NMR of a New Chelate Phosphine Linker System, and Catalysis by Rhodium Adducts Thereof

Synthesis, Immobilization, MAS and HR‐MAS NMR of a New Chelate Phosphine Linker System, and Catalysis by Rhodium Adducts Thereof

A Novel Wilkinson’s Type Silica Supported Polymer Catalyst: Insights from Solid-State NMR and Hyperpolarization Techniques

Anchored Wilkinson Catalyst

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