Investigations into the recovery of Wilkinson’s catalyst with silica-immobilised P-donor ligands

Kramer, Jurjen; Nöllen, Erica; Buijs, Wim; Driessen, Willem L.; Reedijk, Jan

doi:10.1016/j.reactfunctpolym.2003.06.001

Cited by 14 publications

(8 citation statements)

References 25 publications

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“…So the shift at 25 corresponds to the attached phosphino group and at 39 to the free group. In any case, the oxidized form of spacer was not confirmed (EA and MAS-NMR [21]). …”

Section: Immobilization Using Covalent Bondingmentioning

confidence: 86%

“…Because the silica materials do not have the optimal group for ligand exchange that is the basis for covalent bond formation, it is necessary to add some ''spacers'' to the material. As a spacer, two different species can be usedaminopropyltriethoxysilane [19], this has the amino group for ligand exchange, and diphenylphosphinoethyltriethoxysilane [20][21][22][23], which has the phenyl group for ligand exchange.…”

Section: Introductionmentioning

confidence: 99%

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Terminal C≡C triple bond hydrogenation using immobilized Wilkinson’s catalyst

et al. 2010

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In this work, we try to hydrogenate selectively phenylacetylene to styrene and 3-phenylpropyne to allylbenzene using immobilized or pure Wilkinson's catalyst. The catalyst was immobilized using two approaches-immobilization using ionic exchange and immobilization using covalent bonding. In the first case, the smectite minerals (hectorite and montmorillonite) were used as the supports. In the second case, MCM-41 and SBA-15 were used as the supports. Both types of immobilization were successful and the solid products were characterized. For the covalent bond formation, it was necessary to first modify the surface of the silica material. The modification was carried out using two substances, one adding an amino group to the silica material, and the second adding a phenyl group to the material. The selectivity of hydrogenation of both substances was higher using heterogeneous catalyst in the case of phenylacetylene. In the case of phenylpropyne, no difference in selectivity using Wilkinson's catalyst in homogeneous or heterogeneous arrangement was observed. The type of immobilization has no influence on either activity or selectivity of catalyst.

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“…So the shift at 25 corresponds to the attached phosphino group and at 39 to the free group. In any case, the oxidized form of spacer was not confirmed (EA and MAS-NMR [21]). …”

Section: Immobilization Using Covalent Bondingmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Terminal C≡C triple bond hydrogenation using immobilized Wilkinson’s catalyst

et al. 2010

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“…[45] Its applications in many organic reactions have induced a strong demand for the efficient separation of catalyst from the product stream. [46] Various attempts towards catalytic applications of the immobilized Wilkinsons catalyst and its analogues have been undertaken previously. [7,[47][48][49][50] Although [RhClA C H T U N G T R E N N U N G (PPh 3 ) 3 ] tethered to the inorganic support has shown high activity and stability during catalytic processes, the structure of the heterogenized catalyst is still under discussion.…”

Section: Introductionmentioning

confidence: 99%

Solid‐State NMR Characterization of Wilkinson’s Catalyst Immobilized in Mesoporous SBA‐3 Silica

Grünberg

Breitzke

et al. 2010

Chemistry A European J

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The Wilkinson's catalyst [RhCl(PPh(3))(3)] has been immobilized inside the pores of amine functionalized mesoporous silica material SBA-3 and The structure of the modified silica surface and the immobilized rhodium complex was determined by a combination of different solid-state NMR methods. The successful modification of the silica surface was confirmed by (29)Si CP-MAS NMR experiments. The presence of the T(n) peaks confirms the successful functionalization of the support and shows the way of binding the organic groups to the surface of the mesopores. (31)P-(31)P J-resolved 2D MAS NMR experiments were conducted in order to characterize the binding of the immobilized catalyst to the amine groups of the linkers attached to the silica surface. The pure catalyst exhibits a considerable (31)P-(31)P J-coupling, well resolvable in 2D MAS NMR experiments. This J-coupling was utilized to determine the binding mode of the catalyst to the linkers on the silica surface and the number of triphenylphosphine ligands that are replaced by coordination bonds to the amine groups. From the absence of any resolvable (31)P-(31)P J-coupling in off-magic-angle-spinning experiments, as well as slow-spinning MAS experiments, it is concluded, that two triphenylphosphine ligands are replaced and that the catalyst is bonded to the silica surface through two linker molecules.

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“…To overcome this difficulty several studies have been done to immobilize homogeneous catalysts on different organic or inorganic supports [1][2][3]. In this context, the sol-gel process is a powerful tool for the immobilization of transition metals [4,5].…”

Section: Introductionmentioning

confidence: 99%