Phenol and dihydroxybenzene hydrogenation catalysts based on polyamide dendrimers and rhodium species

Zakharyan, E. M.; Ma, Gouqiung; Максимов, А. Л.; Караханов, Э. А.; Voronina, Z. D.

doi:10.1134/s0965544114060115

Cited by 11 publications

(7 citation statements)

References 22 publications

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“…Thus, PPI and PAMAM dendrimer network-based catalysts were developed, containing Rh, Ru, and Pd nanoparticles successfully applied for hydrogenation of phenols [ 122 , 127 , 412 ], aromatic [ 127 , 408 , 413 , 414 ], and unsaturated compounds under the moderate conditions (50–90 °C, 10–30 atm. of H 2 ) [ 123 , 128 , 241 , 287 , 409 , 415 ].…”

Section: Dendrimer Cross-linkingmentioning

confidence: 99%

“…In particular, it was found out that Ru catalysts, based on PPI dendrimers, cross-linked with hexamethylene-1,6-diisocyanate (HMDI) [ 122 ], were superior to those of Rh, based on PAMAM dendrimers, analogously cross-linked with 1,6-hexamethylene diisocyanate [ 412 ], in the hydrogenation of mono- and dihydric phenols, exhibiting TOF values up to 240,000 h −1 ( Figure 34 ) [ 122 ]. Analogously, Pd nanoparticles, immobilized in the networks of PPI dendrimers, cross-linked with 4,4′-(3,3′-dimethoxy)diphenyl diisoxyanate (DMDPDI), revealed the efficacy and selectivity in the hydrogenation of phenylacetylene, α,β-unsaturated compounds and conjugated dienes, which were higher than those for Pd catalysts based on DMDPDI cross-linked PAMAM dendrimers ( Figure 35 ) [ 128 , 409 ].…”

Section: Dendrimer Cross-linkingmentioning

confidence: 99%

“…The influence of donor amino groups was found to be essential for the phenol hydrogenation in the presence of Rh and Ru catalysts, especially with regards to hydrogenation of dihydric phenols, such as hydroquinone and resorcinol ( Figure 34 ) [ 122 , 412 ]. In the last case, PPI dendrimers additionally stabilized the enol form for the intermediate product 1,3-cyclohexanedione, making it more liable to the further hydrogenation, thus drastically reducing the negative dendritic effect [ 122 ].…”

Section: Dendrimer Cross-linkingmentioning

confidence: 99%

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Heterogeneous Dendrimer-Based Catalysts

2022

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The present review compiles the advances in the dendritic catalysis within the last two decades, in particular concerning heterogeneous dendrimer-based catalysts and their and application in various processes, such as hydrogenation, oxidation, cross-coupling reactions, etc. There are considered three main approaches to the synthesis of immobilized heterogeneous dendrimer-based catalysts: (1) impregnation/adsorption on silica or carbon carriers; (2) dendrimer covalent grafting to various supports (silica, polystyrene, carbon nanotubes, porous aromatic frameworks, etc.), which may be performed in a divergent (as a gradual dendron growth on the support) or convergent way (as a grafting of whole dendrimer to the support); and (3) dendrimer cross-linking, using transition metal ions (resulting in coordination polymer networks) or bifunctional organic linkers, whose size, polarity, and rigidity define the properties of the resulted material. Additionally, magnetically separable dendritic catalysts, which can be synthesized using the three above-mentioned approaches, are also considered. Dendritic catalysts, synthesized in such ways, can be stored as powders and be easily separated from the reaction medium by filtration/centrifugation as traditional heterogeneous catalysts, maintaining efficiency as for homogeneous dendritic catalysts.

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Section: Dendrimer Cross-linkingmentioning

confidence: 99%

Section: Dendrimer Cross-linkingmentioning

confidence: 99%

Section: Dendrimer Cross-linkingmentioning

confidence: 99%

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Heterogeneous Dendrimer-Based Catalysts

2022

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“…Earlier we proposed an approach for synthesis of efficient heterogeneous catalysts, suggesting preliminary cross-linking of poly(propylene imine) (PPI) or poly(amido amine) (PAMAM) dendrimers by various bifunctional agents, followed by metal nanoparticles impregnation (Scheme 1) [56][57][58][59][60][61]. The presence of amino and/or amido groups in such types of organic ligands provides effective complexation with metal ions, as well as immobilization of metal nanoparticles within a polymeric network.…”

Section: Introductionmentioning

confidence: 99%

“…Scheme 1. (a) Approach for synthesis of nanoheterogeneous catalysts, based on dendrimer cross-linked networks [56][57][58][59]61]; (b) representative structure for Ru nanocatalysts, based on PPI dendrimers of the 3rd generation, cross-linked with hexamethylene diisocyanate (HMDI).…”

Section: Introductionmentioning

confidence: 99%

Dendrimer-Stabilized Ru Nanoparticles Immobilized in Organo-Silica Materials for Hydrogenation of Phenols

et al. 2017

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New hybrid catalysts based on Ru nanoparticles, encapsulated into poly(propylene imine dendrimers), immobilized into silica pores, were synthesized and examined for the hydrogenation of alkyl-substituted phenols. The corresponding alkyl-substituted cyclohexanols were presented as the major reaction products, while incomplete hydrogenation products appeared to be minor. A competition between the sterical factors of dendrimer-containing carriers and the electronic factors of substrate substituents influenced the hydrogenation rate of the alkyl-substituted phenols. The carrier structure was found to have a significant influence on both the physical and chemical properties of the catalysts and their hydrogenation activity. The synthesized hybrid catalysts appeared to be stable after recycling and could be re-used several times without significant loss of activity.

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Selective Levulinic Acid Hydrogenation in the Presence of Hybrid Dendrimer‐Based Catalysts. Part I: Monometallic

et al. 2017

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Hybrid Ru‐containing catalysts, based on poly(propylene imine) (PPI) dendrimers, immobilized in silica pores, were synthesized and characterized by transmission electron microscopy and X‐ray photoelectron spectroscopy. The synthesized Ru catalysts proved their efficiency in the selective hydrogenation of levulinic acid and its esters at 80 °C, 30 bar of H2, and 50 % volume substrate concentration in water. Quantitative yields of γ‐valerolactone were obtained for both micro‐ and mesoporous Ru catalysts within 2 h with catalytic activity as high as 1610 h−1. The reaction rate and selectivity on γ‐valerolactone were found to depend on several factors such as carrier structure, temperature, presence of water, and substrate/Ru ratio. The novelty of these hybrid materials is the presence of both weak acid (SiO2) and organic base centers (dendrimer amino groups), enhancing the dispersion of Ru nanoparticles. The presence of amino groups in the catalyst stabilizes the Ru nanoparticles during the synthesis and promotes the adsorption of levulinic acid on the surface of Ru nanoparticles during the reaction. Synthesized hybrid Ru catalysts can be reused several times without significant loss of activity.

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Phenol and dihydroxybenzene hydrogenation catalysts based on polyamide dendrimers and rhodium species

Cited by 11 publications

References 22 publications

Heterogeneous Dendrimer-Based Catalysts

Heterogeneous Dendrimer-Based Catalysts

Dendrimer-Stabilized Ru Nanoparticles Immobilized in Organo-Silica Materials for Hydrogenation of Phenols

Selective Levulinic Acid Hydrogenation in the Presence of Hybrid Dendrimer‐Based Catalysts. Part I: Monometallic

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