Study on catalysis by carbonyl cluster-derived SiO2-supported rhodium for ethylene hydroformylation

Huang, Lin; Xu, Yide; Guo, Weihua; Liu, Anming; Li, Darning; Guo, Xiexian

doi:10.1007/bf00806102

Cited by 38 publications

(26 citation statements)

References 36 publications

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“…We consider these observations to be strong evidence that propionaldehyde formation occurs more favorably on undercoordinated Rh sites over the hd p i ¼ 7.1 nm to 2.5 nm size range. This observation is consistent with and corroborated by previous technical catalyst studies of C 2 H 4 hydroformylation on supported Rh catalysts, which show a similar relationship between dispersion and propionaldehyde TOF (18,19).…”

Section: Discussionsupporting

confidence: 92%

“…Studies of propionaldehyde decomposition on Rh surfaces under ultrahigh vacuum (UHV) conditions, which produces H 2 , CO, and ethyl species (along with surface C), also supports these general reaction steps (20). Interestingly, surface coordination of adsorbed CO on Rh also appears to influence its reactivity for CO insertion reactions; for example, linear bound CO appears to be more reactive than CO bound to Rh in a dispersed and/or carbonyl state (e.g., gem-dicarbonyl RhðCOÞ 2 ) (16,19). The effect of Rh particle size on CO insertion activity has been studied to a lesser extent.…”

mentioning

confidence: 99%

“…Insightful studies by Chuang and coworkers (14)(15)(16)(17) and others (18,19) have investigated C 2 H 4 hydroformylation on oxide supported Rh particles to gain information on the reaction mechanism and reactivity of various adsorbed CO surface species. Motivated by the desire to understand oxygenate reaction pathways in CO hydrogenation catalysis, investigators have utilized C 2 H 4 hydroformylation as a probe reaction to understand CO insertion into adsorbed surface ethyl species (R-C 2 H 5 ), without the complications of the CO dissociation step.…”

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confidence: 99%

“…Studies of C 2 H 4 hydroformylation on cluster derived (19) and traditional (18) Rh powder catalysts have shown that propionaldehyde formation (TOF) is increased as Rh dispersion is increased. Competing ethylene hydrogenation TOF was observed to be structure insensitive over this particle dispersion range in one case (19), but structure sensitive in another study, exhibiting a maximum activity near 4 nm (18). Studies of Rh alloy surfaces (e.g., RhZn (21), RhIr (22), and RhS (23)) have suggested isolated Rh sites on alloy surfaces are favorable for CO insertion under CO hydrogenation or hydroformylation conditions.…”

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confidence: 99%

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Planar oxide supported rhodium nanoparticles as model catalysts

McClure

Lundwall²,

Goodman³

2010

Proc. Natl. Acad. Sci. U.S.A.

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C 2 H 4 ∕CO∕H 2 reaction is investigated on Rh∕SiO 2 model catalyst surfaces. Kinetic reactivity and infrared spectroscopic measurements are investigated as a function of Rh particle size under near atmospheric reaction conditions. Results show that propionaldehyde turnover frequency (TOF) (CO insertion pathway) exhibits a maximum activity near hd p i ¼ 2.5 nm. Polarization modulation infrared reflection absorption spectroscopy under CO and reaction (C 2 H 4 ∕CO∕H 2 ) conditions indicate the presence of Rh carbonyl species (RhðCOÞ 2 , Rh(CO)H) on small Rh particles, whereas larger particles appear resistant to dispersion and carbonyl formation. Combined these observations suggest the observed particle size dependence for propionaldehyde production via CO insertion is driven by two factors: (i) an increase in propionaldehyde formation on undercoordinated Rh sites and (ii) creation of carbonyl hydride species (Rh(CO)H)) on smaller Rh particles, whose presence correlates with the lower activity for propionaldehyde formation for hd p i < 2.5 nm.Ethylene hydroformylation | CO insertion | polarization modulation infrared reflection absorption spectroscopy | Rh/SiO2 A complicating effect of understanding the structure-activity relationships of heterogeneous catalytic reactions at ambient pressures (near 1 atm or above) is the known ability of reactant gas environments to alter the morphology, particle dispersion, and even the types of adsorbates present on certain supported nanoparticle (NP) systems (1-4). For example, elevated pressure CO ambients have been shown to oxidatively disrupt and disperse Rh nanoparticles, creating highly dispersed gem-dicarbonyl species RhðCOÞ 2 on oxide supports (1-3, 5-8). Under elevated pressure (CO∕H 2 ) and (CO 2 ∕H 2 ) hydrogenation reaction conditions, Rh(CO)H carbonyl hydride species can also be formed (3, 9-12). The creation and stability of such carbonyl species (RhðCOÞ 2 , Rh(CO)H) can depend on particle size, gas pressure, and surface temperature. The cumulative effect of such factors could potentially have an important effect on the overall catalytic properties of the supported Rh NP surface, especially for catalytic reactions involving surface bound CO. Developing an understanding of how such factors can affect the catalytic properties of supported Rh NPs is important from a fundamental surface chemistry perspective. Unraveling these details will require the ability to conduct spectroscopic and kinetic investigations of an informative probe reaction (i) under near atmospheric reaction conditions and (ii) on supported Rh nanoparticles surfaces with well defined initial particle size distributions.CO insertion into adsorbed alkyl groups (R-C x H y ) to form oxygenates (e.g., alcohols, aldehydes) is an important reaction step in many heterogeneous catalytic reactions. For example, C 2 H 4 hydroformylation (C 2 H 4 þ CO þ H 2 ) is a well known reaction for the synthesis of aldehydes via the CO insertion reaction (13). Insightful studies by Chuang and coworkers (14-17) and others (...

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Section: Discussionsupporting

confidence: 92%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Planar oxide supported rhodium nanoparticles as model catalysts

McClure

Lundwall²,

Goodman³

2010

Proc. Natl. Acad. Sci. U.S.A.

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show abstract

“…Although hydroformylation of alkenes by heterogeneous catalysts is less extensively studied [22][23][24] than that by homogeneous transition metal complexes [25,26], heterogeneous hydroformylation is a promising process from academic and practical points of view. Therefore, we proposed to modify Rh/SiO 2 with triphenyl phosphine (PPh 3 ), in the hope that there might be chemical adsorption of PPh 3 on Rh/SiO 2 , which may promote the in situ growth of the active species for hydroformylation in syngas atmosphere, and that the problem of metal leaching might be resolved by directly fastening the metal particles on the support.…”

Section: Introductionmentioning

confidence: 99%