Pd Nanoparticles in Dendrimers Immobilized on Silica–Polyamine Composites as Catalysts for Selective Hydrogenation

Караханов, Э. А.; Maximov, A. L.; Kardasheva, Yu. S.; Semernina, V. A.; Zolotukhina, A. V.; Иванов, А. Л.; Abbott, Geoffrey; Rosenberg, Edward; Винокуров, В. А.

doi:10.1021/am501528a

Cited by 68 publications

(113 citation statements)

References 63 publications

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“…12,21,27–32 Not only are the conversion yields and selectivity superior but also the reaction conditions (room temperature and atmospheric pressure) are much friendlier than any known homogenous and heterogeneous catalysts tested for diene hydrogenation. Since both dienes and terminal alkenes are potential monomers for the polymerization reaction, C8 PdNP could either hydrogenate the dienes by a 1,4-addition reaction or isomerize terminal alkenes to internal alkenes under mild reaction conditions, so that the deterioration of petroleum products can be effectively prevented by limiting the potential polymerization in the petroleum pyrolysis process.…”

Section: Resultsmentioning

confidence: 99%

Alkanethiolate-capped palladium nanoparticles for selective catalytic hydrogenation of dienes and trienes

Chen

Shon

2017

Catal. Sci. Technol.

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Selective hydrogenation of dienes and trienes is an important process in the pharmaceutical and chemical industries. Our group previously reported that the thiosulfate protocol using a sodium S-alkylthiosulfate ligand could generate catalytically active Pd nanoparticles (PdNP) capped with a lower density of alkanethio-late ligands. This homogeneously soluble PdNP catalyst offers several advantages such as little contamination via Pd leaching and easy separation and recycling. In addition, the high activity of PdNP allows the reactions to be completed under mild conditions, at room temperature and atmospheric pressure. Herein, a PdNP catalyst capped with octanethiolate ligands (C8 PdNP) is investigated for the selective hydrogenation of conjugated dienes into monoenes. The strong influence of the thiolate ligands on the chemical and electronic properties of the Pd surface is confirmed by mechanistic studies and highly selective catalysis results. The studies also suggest two major routes for the conjugated diene hydrogenation: the 1,2-addition and 1,4-addition of hydrogen. The selectivity between two mono-hydrogenation products is controlled by the steric interaction of substrates and the thermodynamic stability of products. The catalytic hydrogenation of trienes also results in the almost quantitative formation of mono-hydrogenation products, the isolated dienes, from both ocimene and myrcene.

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Section: Resultsmentioning

confidence: 99%

Alkanethiolate-capped palladium nanoparticles for selective catalytic hydrogenation of dienes and trienes

Chen

Shon

2017

Catal. Sci. Technol.

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“…3b, c). The latter is typical for Pd catalysts based on the PPI dendrimers, cross-linked with the hydrophobic diisocyanates or grafted to the silica surface, synthesized using wetness impregnation of Pd(OAc) 2 from chloroform at 70°C [45,95]. One can assume, that under the temperatures of 70-90°C poly(ethylene oxide) linking chains are sharply contracted [5,61,66]; as a result, PPI dendrimers, having higher LCSTs [43,50,67], compared with PEGs, appeared in the close proximity to each other.…”

Section: Synthesis Of Thermo-responsive Hybridmentioning

confidence: 99%

“…Due to the latter, as well as a large number of donor coordinating groups and the great possibilities for the modification of surface groups, specifying ligand solubility in the reaction medium and substrate affinity, dendrimers have already found their application in catalysis [32][33][34][35], in particular, in the hydrogenation of alkenes [36][37][38][39][40], aromatic compounds [36,41] and phenols [42], semihydrogenation of alkynes [43][44][45] and dienes [39,[43][44][45][46][47], hydroformylation [48], Waker oxidation [49], cross-coupling [40,[50][51][52][53][54][55][56][57] and oxidative coupling [58] reactions. Homogeneous dendritic catalysts can be repeatedly used, first of all, by their separation in the second phase, when the appropriate solvent is added [35,37,42,44,49,55,59], or cooling the reaction mixture below upper critical solution temperature (UCST) [33,43,50].…”

Section: Introductionmentioning

confidence: 99%

Thermo-responsive Ruthenium Dendrimer-based Catalysts for Hydrogenation of the Aromatic Compounds and Phenols

Караханов

Maximov

Zolotukhina

et al. 2016

J Inorg Organomet Polym

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In this work thermo-responsive ruthenium catalysts, based on the poly(propylene imine) dendrimers cross-linked with the poly(ethylene glycol) diglycidyl ether, have been prepared for the first time. The materials obtained were characterized by X-ray photoelectron spectroscopy and transmission electron microscopy, and tested in the phenol and benzene hydrogenation. Conditions for the metal impregnation into the polymeric matrix were demonstrated to have a great influence both on physical chemical properties of the synthesized catalysts (metal loading, mean particles size, surface structure etc.), and, as a consequence, on their hydrogenation activity and thermoresponsive properties.

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“…The first one was the immobilization of ready dendrimers (not dendron grafting) on the silica polyamine composite via Mannich reaction (Scheme S1) . Herein anchoring the dendrimers was performed, considering the space, occupied by the latters on surface of the carrier.…”

Section: Introductionmentioning

confidence: 99%

Dendrimer‐Encapsulated Pd Nanoparticles, Immobilized in Silica Pores, as Catalysts for Selective Hydrogenation of Unsaturated Compounds

et al. 2019

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Heterogeneous Pd‐containing nanocatalysts, based on poly (propylene imine) dendrimers immobilized in silica pores and networks, obtained by co‐hydrolysis in situ, have been synthesized and examined in the hydrogenation of various unsaturated compounds. The catalyst activity and selectivity were found to strongly depend on the carrier structure as well as on the substrate electron and geometric features. Thus, mesoporous catalyst, synthesized in presence of both polymeric template and tetraethoxysilane, revealed the maximum activity in the hydrogenation of various styrenes, including bulky and rigid stilbene and its isomers, reaching TOF values of about 230000 h −1 . Other mesoporous catalyst, synthesized in the presence of polymeric template, but without addition of Si(OEt) 4 , provided the trans ‐cyclooctene formation with the selectivity of 90–95 %, appearing as similar to homogeneous dendrimer‐based catalysts. Microporous catalyst, obtained only on the presence of Si(OEt) 4 , while dendrimer molecules acting as both anchored ligands and template, demonstrated the maximum activity in the hydrogenation of terminal linear alkynes and conjugated dienes, reaching TOF values up to 400000 h −1 . Herein the total selectivity on alkene in the case of terminal alkynes and conjugated dienes reached 95–99 % even at hydrogen pressure of 30 atm. The catalysts synthesized can be easily isolated from reaction products and recycled without significant loss of activity.

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Pd Nanoparticles in Dendrimers Immobilized on Silica–Polyamine Composites as Catalysts for Selective Hydrogenation

Cited by 68 publications

References 63 publications

Alkanethiolate-capped palladium nanoparticles for selective catalytic hydrogenation of dienes and trienes

Alkanethiolate-capped palladium nanoparticles for selective catalytic hydrogenation of dienes and trienes

Thermo-responsive Ruthenium Dendrimer-based Catalysts for Hydrogenation of the Aromatic Compounds and Phenols

Dendrimer‐Encapsulated Pd Nanoparticles, Immobilized in Silica Pores, as Catalysts for Selective Hydrogenation of Unsaturated Compounds

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