Long-chain alcohols from syngas

Frennet, Alfred; Hubert, Claude; Ghenne, Eric; Chitry, Véronique; Kruse, Norbert

doi:10.1016/s0167-2991(00)80598-4

Cited by 6 publications

(8 citation statements)

References 8 publications

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“…In most catalysts of the present study, Mg (also coprecipitated into an oxalate form) has been used as a dispersant. The preparation and characterization of the catalysts are described elsewhere. , The gas composition is continuously analyzed at the outlet of the reactor by means of a differentially pumped quadrupole mass spectrometer (Balzers QMG 420).…”

Section: Methodsmentioning

confidence: 99%

“…Due to variations of the catalyst activity while performing transients, variations of the volumetric flow rate have to be expected. This is taken into account by using an inert internal standard 29 (Ar, Ne, He, ...), the partial pressure of which is inversely proportional to the volumetric flow rate.…”

Section: Methodsmentioning

confidence: 99%

“…We mention that surface areas of powder samples can be easily measured by BET at any time in the CTK apparatus once the volumetric outflow has been determined. 29 2.2. Experimental Details of the CKT Method, Apparatus, and Catalysts.…”

Section: Methodsmentioning

confidence: 99%

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Mechanism and Kinetics of the Catalytic CO−H₂ Reaction: An Approach by Chemical Transients and Surface Relaxation Spectroscopy

et al. 2004

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The aim of this paper is to demonstrate the importance of providing time-resolved information in catalysis research. Two truly in situ methods will be presented and compared for their merits and drawbacks: chemical transient kinetics (CTK) and pulsed field desorption mass spectrometry (PFDMS). The presentation will be given by way of example choosing the syngas (CO/H2) reaction over cobalt-based catalysts as a catalytic process. Despite numerous efforts in the past, the mechanism of this reaction is still under debate. In CTK the reaction is studied on a metal-supported catalyst under flow conditions in a pressure range extending from atmospheric pressure down to 100 Pa. Sudden changes in the partial pressures of the reactants then allow following the relaxation to either steady-state conditions ("transients") or cleanoff ("back transients"). In PFDMS short field pulses of several volts per nanometer are applied to a model catalyst which resembles a single metal particle grain (a "tip"). These pulses intervene during the ongoing reaction under flow conditions at pressures ranging from 10(-1) to 10(-5) Pa and cause field desorption of adsorbed species. This method is particularly suited to detect reaction intermediates in a time-dependent manner since the repetition frequency of the pulses can be systematically varied. It is shown that both methods lead to complementary results. While CTK allows conclusions on the mechanism of CO hydrogenation by following the time-dependent formation of hydrocarbon species, PFDMS provides insight into the initial steps leading to adsorbed CxHy species. A quantitative assessment of the CTK data allows the demonstration that the catalyst under working conditions is in an oxidized rather than metallic state. The initial steps to oxidation are also traced by PFDMS. Most importantly, however, CTK results allow formulation of a reaction mechanism that is common for both hydrocarbon and oxygenate formation and is based on the occurrence of a formate-type species as the most abundant surface intermediate.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Mechanism and Kinetics of the Catalytic CO−H₂ Reaction: An Approach by Chemical Transients and Surface Relaxation Spectroscopy

et al. 2004

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“…17 Catalysts in these studies were prepared via mixed-metal oxalate precursors in the absence of a generic support material. 18 In these precursors, double chelating oxalate ligands are linking transition metal cations to form neutral [Me(H 2 O) x (C 2 O 4 )] n polymeric strands reminiscent of the basic structural features occurring in metal organic frameworks (MOF). Importantly, several metals can be coprecipitated as oxalates into common polymeric strands and pure metal, metal oxide or mixed metal/metal oxide nanoparticles are obtained on mild heating through oxalate rejection as CO 2 or CO, respectively.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Recently, alkali-promoted CoMn catalysts allowed straight-chain aldehydes and alcohols to be produced with a combined selectivity of about 50 wt %, whereof up to 97% were allotted to aldehydes . Catalysts in these studies were prepared via mixed-metal oxalate precursors in the absence of a generic support material . In these precursors, double chelating oxalate ligands are linking transition metal cations to form neutral [Me(H 2 O) x (C 2 O 4 )] n polymeric strands reminiscent of the basic structural features occurring in metal organic frameworks (MOF).…”

Section: Introductionmentioning

confidence: 99%

Terminal Amines, Nitriles, and Olefins through Catalytic CO Hydrogenation in the Presence of Ammonia

et al. 2021

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We report on the "one stepone pot" synthesis of chain-lengthened aliphatic amines and nitriles from CO/H 2 /NH 3 gas feeds using potassium-promoted Co/MnO x catalysts prepared via MOF-type (metal organic framework) mixed-metal Co−Mn oxalates. We show that the reaction can be tuned via adjustments of the H 2 / CO ratio so as to favor the production of either terminal amines or nitriles. Besides regioselective nitrogen functionalization, ammonia addition to CO/H 2 strongly favors chain-lengthened olefin formation at the expense of alkanes. Linear Anderson−Schulz− Flory behavior, independent of the H 2 /CO ratio, is found for the sum of C 4+ nitrogencontaining compounds and olefins but not for alkanes. X-ray diffraction reveals Co to Co 2 C bulk reconstruction to occur for CO/H 2 feeds in either the presence or absence of ammonia. X-ray photoelectron spectroscopy provides evidence for nitrogen to modify the near-surface composition by forming Co−C−N chemical structures.

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High Catalytic Activity in CO Oxidation over MnO x Nanocrystals

et al. 2009

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Manganese oxides of various stoichiometry were prepared via Mn-oxalate precipitation followed by thermal decomposition in the presence of oxygen. A nonstoichiometric manganese oxide, MnO x (x = 1.61…1.67) was obtained by annealing at 633 K and demonstrated superior CO oxidation activity, i.e. full CO conversion at room temperature and below. The activity gradually decreased with time-on-stream of the reactants but could be easily recovered by heating at 633 K in the presence of oxygen. CO oxidation over MnO x in the absence of oxygen proved to be possible with reduced rates and demonstrated a Mars-van Krevelen-type mechanism to be in operation. A TEM structural analysis showed the MnO x phase to form microrods with large aspect ratio which broke up into nanocrystalline manganese oxide (MnO x ) particles with diameters below 3 nm and a BET specific surface area of 525 m 2 /g. Annealing at 798 K rather than 633 K produced well crystalline Mn 2 O 3 which showed lower CO oxidation activity, i.e. 100% CO conversion at 335 K. The catalytic performance in CO oxidation of various Mn-oxides either studied in this work or elsewhere was compared on the basis of specific reaction rates.

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Long-chain alcohols from syngas

Cited by 6 publications

References 8 publications

Mechanism and Kinetics of the Catalytic CO−H₂ Reaction: An Approach by Chemical Transients and Surface Relaxation Spectroscopy

Mechanism and Kinetics of the Catalytic CO−H₂ Reaction: An Approach by Chemical Transients and Surface Relaxation Spectroscopy

Terminal Amines, Nitriles, and Olefins through Catalytic CO Hydrogenation in the Presence of Ammonia

High Catalytic Activity in CO Oxidation over MnO x Nanocrystals

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Long-chain alcohols from syngas

Cited by 6 publications

References 8 publications

Mechanism and Kinetics of the Catalytic CO−H2 Reaction: An Approach by Chemical Transients and Surface Relaxation Spectroscopy

Mechanism and Kinetics of the Catalytic CO−H2 Reaction: An Approach by Chemical Transients and Surface Relaxation Spectroscopy

Terminal Amines, Nitriles, and Olefins through Catalytic CO Hydrogenation in the Presence of Ammonia

High Catalytic Activity in CO Oxidation over MnO x Nanocrystals

Contact Info

Product

Resources

About

Mechanism and Kinetics of the Catalytic CO−H₂ Reaction: An Approach by Chemical Transients and Surface Relaxation Spectroscopy

Mechanism and Kinetics of the Catalytic CO−H₂ Reaction: An Approach by Chemical Transients and Surface Relaxation Spectroscopy