Palladium(0) supported on carbon nanotubes as an efficient catalyst of the C C bond hydrogenation

Starodubtseva, E. V.; Vinogradov, M. G.; Turova, O. V.; Бумагин, Н. А.; Rakov, E. G.; Sokolov, V. I.

doi:10.1016/j.catcom.2009.03.012

Cited by 34 publications

(10 citation statements)

References 10 publications

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“…(C). Hydrogen uptake measured at ambient temperature (Table ) was low suggesting limited capacity to chemisorb H 2 , as has been noted elsewhere for a range of Au systems . Uptake was appreciably higher at 423 K (median reaction temperature), indicating that H 2 chemisorption on supported Au is an activated process.…”

Section: Resultssupporting

confidence: 65%

“…Hydrogen uptake measured at ambient temperature (Table 1) was low suggesting limited capacity to chemisorb H 2 , as has been noted elsewhere for a range of Au systems. 25,40,41 Uptake was appreciably higher at 423 K (median reaction temperature), indicating that H 2 chemisorption on supported Au is an activated process. Although we could find no reported chemisorption values to relate to our measurements, van Bokhoven and co-workers 39,42 and Lin et al 43 have proposed enhanced H 2 activation on Au/Al 2 O 3 and Au/TiO 2 , respectively, at higher temperatures.…”

Section: Catalytic Proceduresmentioning

confidence: 98%

“…23 We have now extended that work to consider the catalytic action of Au/Al 2 O 3 in selective phenylacetylene to styrene conversion, assessing the effects of temperature and H 2 partial pressure as critical process variables. Drawing on the published liquid phase catalytic work where supported Pd was the predominant catalyst system, 4,6,[24][25][26][27] we have employed Pd/Al 2 O 3 as benchmark and correlate catalyst testing with structural characterisation.…”

Section: Introductionmentioning

confidence: 99%

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Gas phase selective hydrogenation of phenylacetylene to styrene over Au/Al₂O₃

Wang

Keane

2019

J of Chemical Tech & Biotech

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BACKGROUND Trace quantities of phenylacetylene can poison styrene polymerisation catalysts. The phenylacetylene content must be less than 10 ppm and selective hydrogenation (to styrene) is viewed as a viable process solution. High styrene selectivities have been achieved in batch liquid phase operations while a switch from conventional batch liquid to continuous gas phase reaction presents process advantages in terms of higher throughput and enhanced productivity. We aim to provide the first direct comparison of Au/Al2O3 and Pd/Al2O3 in gas phase continuous catalytic hydrogenation of phenylacetylene. RESULTS Temperature programme reduction (TPR) generated metal particles at the nano‐scale (mean size = 3.0–4.3 nm), with evidence of electron donation from the aluminium oxide (Al2O3) carrier. Pd/Al2O3 exhibited a greater specific hydrogen (H2) uptake capacity than Au/Al2O3 under reaction conditions to deliver appreciably higher turnover frequencies (TOF) for reaction in excess H2. Stepwise hydrogenation predominated over Au/Al2O3 with 100% selectivity to styrene at 353 K where an increase in temperature favoured subsequent hydrogenation to ethylbenzene. Under the same conditions, Pd/Al2O3 was non‐selective, activating styrene to generate ethylbenzene with a greater contribution of direct phenylacetylene hydrogenation to ethylbenzene at higher temperature. CONCLUSION Kinetic analysis has revealed stepwise phenylacetylene hydrogenation in excess H2 over Au/Al2O3 with 100% selectivity to styrene. Stepwise hydrogenation also prevailed over Pd/Al2O3 at the lower temperature but surface activation of styrene coupled with enhanced H2 dissociation generated significant ethylbenzene. Decreasing inlet H2/phenylacetylene (to 1 mol/mol) over Pd/Al2O3 lowered rate where the activity/selectivity profile overlapped that exhibited by Au/Al2O3 in excess H2. © 2019 Society of Chemical Industry

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Section: Resultssupporting

confidence: 65%

Section: Catalytic Proceduresmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Gas phase selective hydrogenation of phenylacetylene to styrene over Au/Al₂O₃

Wang

Keane

2019

J of Chemical Tech & Biotech

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“…The partial hydrogenation of diphenylacetylene to cis-stilbene occurred at 333K. A comparison of the performance of Pd@L 5/6 with other heterogeneous Pd catalysts, such as Pd-Nps supported onto carbon without additional organic modifiers led to much lower chemoselectivities (i.e., styrene <80% and cis-stilbene 85%) [38]. The heterogeneous PLA-stereocomplex-based Pd catalysts were easily recovered from the catalytic solution simple by centrifugation of the catalytic THF solution followed by decantation of the solution in air atmosphere.…”

Section: Time (H) Conversion (%) Tof (H -1 ) Chemoselectivity (%) Regmentioning

confidence: 99%

Palladium‐Based Catalysts‐Supported onto End‐Functionalized Poly(lactide) for C–C Double and Triple Bond Hydrogenation Reactions

Frediani¹,

Oberhauser²,

Rosi³

et al. 2017

New Advances in Hydrogenation Processes - Fundamentals and Applications

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Poly(lactide) (PLA), which is the polymer that will be discussed in this chapter, was functionalized with nitrogen containing aromatic groups by means ring opening polymerization (ROP) reactions. The obtained macroligands were successfully employed to coordinate Pd(II), which chemoselectively hydrogenated αβ-unsaturated carbonyl compounds to give the saturated counterparts as main product. The catalyst could be easily recycled upon a simple filtration process. End-functionalized isotactic PLA chains were used to generate stereocomplexes, featured by a higher thermal and hydrolytic resistance. The chemical nature of the nitrogen ligand introduced at the chain end of PLA was exploited to stabilize Pdnanoparticles (Pd-NP s) by interactions of the aromatic or nitrogen functionality with the NP s-surface. The polymer-anchored Pd-NP s were generated by a classical approach which comprised the coordination of Pd(II) by the functional group followed by reduction with hydrogen or by the metal vapor synthesis technique. The polymersupported Pd-NP s were successfully applied to catalyze the selective hydrogenation of alkynes to the corresponding alkene and cinnamylalcohol to the corresponding saturated aldehyde. In this book chapter the synthesis and structure-performance relationship of the new hydrogenation catalysts will be discussed.

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“…29 The C≡C bond of tolane, phenylacetylene and 1-heptyne were hydrogenated to give a mixture of intermediate ethylenic and completely reduced hydrocarbons. 30 The composition of hydrogenation products depends greatly on the structure of the starting reagent and reaction conditions. CNT-supported metallic NPs including Pt, Rh, and bimetallic Pd-Rh were reported to be effective catalysts for the hydrogenation of neat benzene at room temperature, which cannot be achieved by carbon-based Pd and Rh catalysts available commercially.…”

Section: Alkene and Alkyne Hydrogenationmentioning

confidence: 99%

Heterogeneous Catalysis on Nanostructured Carbon Material Supported Catalysts

2015

Nanostructured Carbon Materials for Catalysis

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For almost twenty years there has been an increasing interest in the use of nanostructured carbon materials as catalyst supports. 1-16 Following the nanotechnology wave, a wide variety of carbon nanomaterials has been investigated as catalyst supports, including fullerenes, CNTs, CNFs, carbon onions, nanodiamonds, FLG or GO. CNTs and CNFs, which constitute a new family of support offering a good compromise between the advantages of AC and high surface area graphite have been particularly studied. The main advantages offered by CNT or CNF supports are: 17 (i) the high purity of the material can avoid self-poisoning; (ii) the mesoporous nature of these supports can be of interest for liquid-phase reactions, thus limiting the mass transfer; (iii) the high thermal conductivity that limits hot-spots that can damage the catalyst; (iv) their well-defined and tunable structure; (v) their rich surface chemistry that offers numerous perspectives for adsorption and dispersion of the active phase; and (vi) the specific metal support interactions, due to high electrical conductivity of the support and to the tunable orientation of the graphene layers, that exist and that can directly affect catalytic activity and selectivity. The possibility to perform catalysis in a confined space is also of great interest. 6,18 From a theoretical viewpoint, graphene provides the ultimate two-dimensional model of a catalytic support. The reason is related to its high theoretical surface area (ca. 2630 m 2 g −1 ), high conductivity, unique graphitized basal plane structure and chemical tolerance. FLG,

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Palladium(0) supported on carbon nanotubes as an efficient catalyst of the C C bond hydrogenation

Cited by 34 publications

References 10 publications

Gas phase selective hydrogenation of phenylacetylene to styrene over Au/Al₂O₃

Gas phase selective hydrogenation of phenylacetylene to styrene over Au/Al₂O₃

Palladium‐Based Catalysts‐Supported onto End‐Functionalized Poly(lactide) for C–C Double and Triple Bond Hydrogenation Reactions

Heterogeneous Catalysis on Nanostructured Carbon Material Supported Catalysts

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Palladium(0) supported on carbon nanotubes as an efficient catalyst of the C C bond hydrogenation

Cited by 34 publications

References 10 publications

Gas phase selective hydrogenation of phenylacetylene to styrene over Au/Al2O3

Gas phase selective hydrogenation of phenylacetylene to styrene over Au/Al2O3

Palladium‐Based Catalysts‐Supported onto End‐Functionalized Poly(lactide) for C–C Double and Triple Bond Hydrogenation Reactions

Heterogeneous Catalysis on Nanostructured Carbon Material Supported Catalysts

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Gas phase selective hydrogenation of phenylacetylene to styrene over Au/Al₂O₃

Gas phase selective hydrogenation of phenylacetylene to styrene over Au/Al₂O₃