Dehydrogenation of propane over various chromium-modified MFI-type zeolite catalysts

Tsiatouras, V.A.; Katranas, T.; Triantafillidis, Costas S.; Vlessidis, Athanasios G.; Paulidou, E.; Evmiridis, Nicholaos P.

doi:10.1016/s0167-2991(02)80109-4

Cited by 13 publications

(10 citation statements)

References 24 publications

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“…Therefore, the incorporation of transition metal ions into zeolites leads to interesting bifunctional catalysts in which metal and acid centers can act simultaneously. 111 The transition metals, such as Ni, Co, Zn, Cu, Cr, and Mn, introduced into pentasil type zeolites are generally used as active components for hydrogenation or dehydrogenation, 112,113 or aromatization reactions. 114,115 The reported results depict that Co, Cu, Zn, and Ag loaded sites on HZSM-5 zeolites accelerate the dehydrogenation cracking and cyclo-dehydrogenation reactions.…”

Section: Feedstockmentioning

confidence: 99%

Crude oil to chemicals: light olefins from crude oil

Corma

Corresa

Mathieu

et al. 2017

Catal. Sci. Technol.

279

163

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Section: Feedstockmentioning

confidence: 99%

Crude oil to chemicals: light olefins from crude oil

Corma

Corresa

Mathieu

et al. 2017

Catal. Sci. Technol.

279

163

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“…The different chromium-containing zeolites have been synthesized using direct hydrothermal synthesis and conventional postsynthesis procedures such as ion exchange and/or impregnation. [9][10][11][12][13][14][15][16][17][18][19][20][21] With these preparation methods, different chromium species can be formed in the zeolites: isolated lattice and extralattice Cr species, Cr oligomers, and/or Cr oxides. 10,13,15,16,19,20 Several studies have tried to attribute the activity and/or selectivity of a chromium zeolite to one of these species.…”

Section: Introductionmentioning

confidence: 99%

State of Chromium in CrSiBEA Zeolite Prepared by the Two-Step Postsynthesis Method: XRD, FTIR, UV−Vis, EPR, TPR, and XAS Studies

Dzwigaj

Shishido

2008

J. Phys. Chem. C

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Cr x SiBEA zeolites (x ) 0.2, 0.9, and 3.4 Cr wt %) are prepared by a two-step postsynthesis method that allows controlling the introduction of chromium ions in the zeolite structure. The introduction of Cr ions in vacant T-sites and their reaction with silanol groups are evidenced by XRD and FTIR, respectively. It generates Brønsted acidic sites as shown by FTIR of pyridine adsorbed as a molecular probe. The state of chromium species is characterized by DR UV-vis, EPR, TPR, and XAS. The combined use of these techniques allows one to show that the state of chromium species depend on the treatment condition of CrSiBEA samples. In the as-prepared Cr x SiBEA samples chromium species are mainly present as isolated mononuclear octahedral Cr(III) species, as evidenced by DR UV-vis and XAS spectroscopy. In calcined Cr x SiBEA samples isolated mononuclear tetrahedral Cr(VI) and octahedral Cr(III) species are present as shown by DR UV-vis. After further outgassing under vacuum, part of the isolated mononuclear tetrahedral Cr(VI) species is reduced to pentavalent chromium species as shown by EPR measurements. After rehydration of calcined Cr x SiBEA samples at room temperature less distorted tetrahedral Cr(VI) appear as shown by DR UV-vis. Possible models of mononuclear octahedral Cr(III) and tetrahedral Cr(VI) species in the BEA structure are proposed.

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“…The major methods for acidity modification of ZSM-5 are through alkali treatment, phosphorus, alkaline earth metals (Na, Mg, K, and Ca), and rare earth metals (La and Ce) . Nanometer ZSM-5, single or meso- and microporous composite ZSM-5, and mesoporous ZSM-5 have been successfully synthesized to increase the number of active sites. − The incorporation of transition metals (Zn, Co, Cu, and Ni) into ZSM-5 can form a bifunctional catalyst, where metal and acid sites can act simultaneously, to improve the yield of light olefins because transition metals are generally used as active components for hydrogenation or dehydrogenation . Zn and Ga are the driving forces for dehydrogenation by combining H atoms that form during the activation of C–H at Brønsted acid sites .…”

Section: Introductionmentioning

confidence: 99%

“…21−23 The incorporation of transition metals (Zn, Co, Cu, and Ni) into ZSM-5 can form a bifunctional catalyst, where metal and acid sites can act simultaneously, to improve the yield of light olefins because transition metals are generally used as active components for hydrogenation or dehydrogenation. 24 Zn and Ga are the driving forces for dehydrogenation by combining H atoms that form during the activation of C−H at Brønsted acid sites. 25 Also, Au as a dehydrogenation active site has been reported in the catalytic conversion of n-butane, where Au/ZSM-5 can decrease dry gas and aromatics selectivity.…”

Section: Introductionmentioning

confidence: 99%

Insights into Au Nanoparticle Size and Chemical State of Au/ZSM-5 Catalyst for Catalytic Cracking of n-Octane to Increase Propylene Production

et al. 2021

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The cracking of n-octane to propylene was chosen as a model reaction over gold catalysts supported on ZSM-5. Au/ZSM-5 catalysts with a series of Au particle sizes (6.9−10.6 nm) were prepared through deposition−precipitation in which the catalysts were distinguishable and had uniform-sized Au particles. Au/ZSM-5 catalysts with different Au species were obtained by changing the reduction temperature. The crystallinity, textural parameters, and acidity of Au/ZSM-5 were not destroyed compared with those of virgin ZSM-5 through this preparation approach. The influences of Au particle size and Au species are linked to the catalytic activity and selectivity in catalytic cracking reactions to increase propylene production. Metallic gold was found to be dominant for the cracking reaction, and the Au particle size played an important role in the dehydrogenation reaction to produce propylene. The reaction results of real light diesel oil are consistent with octane cracking where a smaller gold particle size provides a better catalytic activity. The effects of the Au chemical state on the catalytic activity and selectivity were also researched, and the Au 0 species was the dominant Au active site for the cracking reaction. A similar conclusion was also verified in the light diesel oil cracking reaction.

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Dehydrogenation of propane over various chromium-modified MFI-type zeolite catalysts

Cited by 13 publications

References 24 publications

Crude oil to chemicals: light olefins from crude oil

Crude oil to chemicals: light olefins from crude oil

State of Chromium in CrSiBEA Zeolite Prepared by the Two-Step Postsynthesis Method: XRD, FTIR, UV−Vis, EPR, TPR, and XAS Studies

Insights into Au Nanoparticle Size and Chemical State of Au/ZSM-5 Catalyst for Catalytic Cracking of n-Octane to Increase Propylene Production

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