Selective hydrogenation of pentynes over PdZr and PdCuZr prepared from amorphous precursors

Varga, Mónika; Molnár, Árpàd; Mohai, M.; Bertóti, I.; Janik‐Czachor, M.; Szummer, A.

doi:10.1016/s0926-860x(02)00227-2

Cited by 22 publications

(18 citation statements)

References 42 publications

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“…semi-hydrogenation selectivity is to add CO to the reaction system, which is believed to displace alkene from the adsorption sites of Pd [14,21], although studies have shown that hydrogenation could be reasonably selective (>80%) even on Pd foils without modifications [22,23]. Many authors believe that alkynes adsorb more selectively on a metal surface, retarding alkene adsorption and hindering its hydrogenation to alkane, while alkynes are present in the reaction mixture [17,24].…”

Section: Figurementioning

confidence: 99%

“…More often, catalyst systems are tested experimentally to evaluate performance. In this regard, Varga et al performed the gas-phase hydrogenation of 1-pentyne and 2-pentyne over PdZr and PdCuZr catalysts [37]. PdZr deactivated easily while the PdCuZr showed selectivity of 80-90% to alkene at 100% conversion, with the principal catalyst in these systems being Pd.…”

Section: Gas-phase Hydrogenationmentioning

confidence: 99%

“…An increase of hydrogen pressure leads to decrease in alkene selectivity similar to what is observed in gasphase reactions. At high H 2 pressures, alkyne hydrogenates mainly nonselectively to alkane, while at lower pressure, the rate of hydrogenation is much slower leading to the selective formation of alkenes [23,34,63].…”

Section: Liquid Phase Hydrogenationmentioning

confidence: 99%

“…reactions. At high H 2 pressures, alkyne hydrogenates mainly nonselectively to alkane, while at lower pressure, the rate of hydrogenation is much slower leading to the selective formation of alkenes [24,26,37]. Conversely, oligomerisation proceeds faster at low hydrogen to alkyne ratio, so some optimal intermediate substrate to hydrogen ratio is important to achieve high selectivity.…”

Section: Effect Of Experimental Conditionsmentioning

confidence: 99%

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The Reduction of Alkynes Over Pd-Based Catalyst Materials - A Pathway to Chemical Synthesis

Ao¹,

Sk²

2017

J Chem Eng Process Technol

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Many reactions, including selective hydrogenation of alkynes, take place on solid surfaces. These reactions are vital in many areas of industry including the manufacture of polymers and fine chemicals such as vitamins, fragrances, and drugs. The choice of a catalyst is a trade-off between activity, selectivity and costs. Palladium-based heterogeneous catalysts are traditionally used for these processes as they provide the activation of hydrogen at room temperatures and offers reasonable selectivity, but these catalysts have a number of practical drawbacks. This review discusses recent research work in the selective hydrogenation of alkynes on palladium-based catalysts, emphasises the mechanism and catalytic materials and important applications including alkyne removal from gasphase alkene precursors for polymer synthesis and liquid phase selective hydrogenation for the synthesis of fine chemicals. Langmuir-Hinshelwood reaction kinetic models, reaction intermediates, formation of carbonaceous layer, the nature of active sites and the effects of reversible and irreversible adsorbates over Pd surface are discussed as well as the factors affecting catalyst activity and selectivity and how these can be optimised in synthetic protocols for these reactions.

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Section: Figurementioning

confidence: 99%

Section: Gas-phase Hydrogenationmentioning

confidence: 99%

Section: Liquid Phase Hydrogenationmentioning

confidence: 99%

Section: Effect Of Experimental Conditionsmentioning

confidence: 99%

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The Reduction of Alkynes Over Pd-Based Catalyst Materials - A Pathway to Chemical Synthesis

Ao¹,

Sk²

2017

J Chem Eng Process Technol

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“…The adsorption of alkyne on the palladium surface has been suggested to be stronger than that of the corresponding alkene [51][52][53][54][55] and thus could prevent the re-adsorption of the product alkene [45,56]. Hence, cis-2-pentene is able to compete for the metal active sites only when most of the 2-pentyne is consumed from the solution, to be further hydrogenated to pentane or converted to its trans-isomer.…”

Section: Comparison Of Bio-pd Ecoli and Pd/al 2 O 3 As Catalysts In mentioning

confidence: 99%

Selective hydrogenation using palladium bioinorganic catalyst

Zhu

Wood

Deplanche

et al. 2016

Applied Catalysis B: Environmental

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a b s t r a c tPalladium bioinorganic catalyst (bio-Pd) was manufactured using bacteria (Desulfovibrio desulfuricans and Escherichia coli) via the reduction of Pd(II) to bio-scaffolded Pd(0) nanoparticles (NPs). The formed Pd NPs were examined using electron microscopy and X-ray powder diffraction methods: a loading of 5 wt% Pd showed an average particle size of ∼4 nm. The catalytic activities of the prepared bio-Pd NPs on both bacteria were compared in two hydrogenation reactions with that of a conventionally supported Pd catalyst (Pd/Al 2 O 3 ). Concentration profiles of the different hydrogenation products were fitted using a Langmuir-Hinshelwood expression. In 2-pentyne hydrogenation, 5 wt% Pd E.coli achieved 100% of 2-pentyne conversion in 20 mins and produced 10.1 ± 0.7 × 10 −2 mol L −1 of desired cis-2-pentene; in contrast 5 wt% Pd/Al 2 O 3 yielded 6.5 ± 0.4 × 10 −2 mol L −1 of cis-2-pentene after 40 mins. In the solvent-free hydrogenation of soybean oil, the use of 5 wt% Pd E.coli yielded cis-C18:1 of 1.03 ± 0.04 mol L −1 and trans-C18:1 of 0.26 ± 0.03 mol L −1 (∼50% less of the latter than 5 wt% Pd/Al 2 O 3 ) after 5 h. Similar results were obtained using bio-Pd E.coli and bio-Pd D.desulfuricans . Bio-Pd was concluded to have the advantage of a lower cis-trans isomerisation in hydrogenation of alkyne/alkenes. Hence biomanufacturing is an environmentally attractive, scalable and facile alternative to conventional heterogeneous catalyst for application in industrial hydrogenation processes. D. desulfuricans is inconvenient to grow at scale but wastes of E. coli are produced from various industrial processes. 'Second life' (i.e. recycled from a pilot scale biohydrogen production process) E. coli cells were used to make bio-Pd catalysts. Although 'bio-Pd secondlife gave a slower conversion rate of 2-pentyne and soybean oil compared to bio-Pd from purpose-grown cells it showed a higher selectivity to the cis-isomer product.

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Metallic Glasses

Baiker

Molnár²

2008

Handbook of Heterogeneous Catalysis

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The sections in this article are Introduction Preparation Chemical and Structural Properties Metallic Glasses in Catalysis Research Research into Metallic Glasses in As‐Quenched State Metallic Glasses as Precursors to Catalytically Active Materials Factors Influencing Chemical and Structural Properties of Catalytic Materials Derived from Metallic Glasses Chemical Composition Chemical and Structural Homogeneity Thermal Stability and Crystallization Behavior Oxidation Behavior Dissolution of Gases Segregation Phenomena Case Studies CO Oxidation Catalysts Prepared from Metallic Glasses Pd / ZrO 2 Catalysts from Amorphous Pd  Zr Alloys Promoted Au  Zr Catalysts from Ternary Au ‐Containing Glassy Alloys Methanation over Ni Alloys Dehydrogenation over Cu  M ( Ti , Zr or Hf ) Catalysts Conclusions and Outlook

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Selective hydrogenation of pentynes over PdZr and PdCuZr prepared from amorphous precursors

Cited by 22 publications

References 42 publications

The Reduction of Alkynes Over Pd-Based Catalyst Materials - A Pathway to Chemical Synthesis

The Reduction of Alkynes Over Pd-Based Catalyst Materials - A Pathway to Chemical Synthesis

Selective hydrogenation using palladium bioinorganic catalyst

Metallic Glasses

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