Mechanism of n-butane skeletal isomerization on H-mordenite and Pt/H-mordenite

Wulfers, Matthew J.; Jentoft, Friederike C.

doi:10.1016/j.jcat.2014.12.035

Cited by 35 publications

(40 citation statements)

References 55 publications

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“…Third, the reaction order with respect to H 2 in n ‐heptane conversion over Pt/SZ is about one, and it is close to zero with respect to alkane, which is quite different from the conventional bifunctional isomerization mechanism on Pt/zeolite catalysts, where the order with respect to H 2 is negative, and with alkane, it lies in 1 to 2 depending on the monomolecular or bimolecular reaction . Last, on the bifunctional isomerization catalysts (Pt/Hβ), Wulfers and Jentoft proposed that a chemical equilibrium between n ‐alkane, n ‐alkene, and H 2 reached inside reactor at 300°C . Under this circumstances, only 13 to 16 ppm of n ‐alkene can be obtained by catalytic dehydrogenation on the metal sites even at 300°C under equilibrium conditions.…”

Section: Strategies For Improving N‐alkane Isomerization Activity Ovementioning

confidence: 97%

“…It is well accepted that the superacidic Brønsted sites are active sites for alkane activation over zeolites by involving a penta‐coordinated carbonium ion as a transition state, which needs to overcome high energy barrier . However, the zeolite‐catalyzed alkane isomerization reaction generally requires much higher reaction temperature compared with the reaction on the SZ . Therefore, the protonation activation of alkanes on SZ catalysts at low reaction temperature has been challenged.…”

Section: Activation Of Alkane Over Sulfated Zirconiamentioning

confidence: 99%

“…The contribution of the two reaction pathways is strongly related to the reactants and reaction conditions. The kinetics and isotope labeling experiments conducted by Wulfers and Jentoft showed that the concentration of alkenes on the catalysts bed had a strong influence on the reaction pathways of alkane isomerization on solid acid catalysts . In effect, the monomolecular reaction, which is kinetically unfavored compared with dimerization reaction, is dominant at low alkene concentration.…”

Section: Reaction and Deactivation Mechanism Of Sz Catalysts In N‐alkmentioning

confidence: 99%

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Alkane isomerization over sulfated zirconia solid acid system

et al. 2020

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Summary Sulfated zirconia (SZ) and its modified versions attract great interest in recent years, because of their promising potential in n‐alkane isomerization. The oxidative and protonation routes are active and interactional in n‐alkane activation over SZ catalysts. The bimolecular reaction becomes dominant with increasing the density of active sites on SZ surface and decreasing the carbon chain of feed. Pentane and hexane are mainly isomerized by protonated cyclopropane mechanism, while which is thermodynamically unflavored for n‐butane isomerization. The deactivation of SZ catalysts is primarily caused by the loss of superacidity and oxidizing ability, resulted from the structure changes of sulfate species. Several strategies for improving the activity of SZ are reviewed. The intrinsic structure‐reactivity relationship of SZ catalysts in alkane isomerization is updated to illuminate the prerequisite for the highly active catalysts and the mechanism of active sites formation. The applications of Pt/SZ in fixed‐bed and unmodified SZ in circulating fluidizing bed in light alkanes isomerization are compared with the conventional technologies based on the chlorinated alumina catalysts. Finally, the future study of SZ catalysts is outlooked from the academic investigations to the industrial applications.

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Section: Strategies For Improving N‐alkane Isomerization Activity Ovementioning

confidence: 97%

Section: Activation Of Alkane Over Sulfated Zirconiamentioning

confidence: 99%

Section: Reaction and Deactivation Mechanism Of Sz Catalysts In N‐alkmentioning

confidence: 99%

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Alkane isomerization over sulfated zirconia solid acid system

et al. 2020

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“…The catalysis is the same as for the hydroisomerisation of n -butane to isobutane ( Section 3.2 ). The mechanism of hydroisomerisation over the zeolite Pt/MOR was discussed in detail in literature [ 44 ].…”

Section: Naphthamentioning

confidence: 99%

Zeolites as Catalysts for Fuels Refining after Indirect Liquefaction Processes

Klerk

2018

Molecules

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The use of zeolite catalysts for the refining of products from methanol synthesis and Fisher–Tropsch synthesis was reviewed. The focus was on fuels refining processes and differences in the application to indirect liquefaction products was compared to petroleum, which is often a case of managing different molecules. Processes covered were skeletal isomerisation of n-butenes, hydroisomerisation of n-butane, aliphatic alkylation, alkene oligomerisation, methanol to hydrocarbons, ethanol and heavier alcohols to hydrocarbons, carbonyls to hydrocarbons, etherification of alkenes with alcohols, light naphtha hydroisomerisation, catalytic naphtha reforming, hydroisomerisation of distillate, hydrocracking and fluid catalytic cracking. The zeolite types that are already industrially used were pointed out, as well as zeolite types that have future promise for specific conversion processes.

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“…Perengkahan nbutana bukan merupakan reaksi dominan pada temperatur rendah, yaitu 350 o C. Pada suhu rendah, reaksi isomerisasi lebih banyak terjadi sehingga selektivitas terhadap isobutana mencapai maksimum, yaitu 63% pada sampel H-K-3 (Tabel 4). Selektivitas isobutana ditemukan lebih tinggi pada temperatur rendah (Wulfers and Jentoft 2015).…”

Section: Perengkahan N-butanaunclassified

Perengkahan n-Butana Menggunakan Katalis Nanopartikel Zeolit Alam Klaten

Kurniawan

Muraza

2018

J. Rekayasa Kim. Lingkung.

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Increasing demand on olefins, high energy consumption of thermal cracking and oil depletion are the driving force to find new process to produce olefins. Catalytic cracking of n-butane is promising route to produce olefins. In this paper, we synthesized nanoparticle from natural zeolites by ball milling-recrystallization method and studied the effect of acid dealumination over the nanozeolites on the catalytic properties. Particle size was evaluated visually by using scanning electron microscope. X-Ray Diffraction analysis was performed to study zeolites phase and its crystallinity. Acid dealumination effect over nanosized mordenite on the acidity were evaluated by ammonia TPD and pyridine FTIR. Textural properties of zeolites were characterized by nitrogen physisorption at -196 oC. The catalysts were tested in a fixed bed reactor for n-butane cracking to olefins product. Various temperature conditions were applied ranging from 350 oC to 650 oC for n-butane cracking in a fixed bed reactor. Conversions of n-butane were 15% and 90% at 350 oC and 650 oC, respectively. Selectivity to olefins was increase from 1% at 350 oC to 47% at 650 oC.

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Mechanism of n-butane skeletal isomerization on H-mordenite and Pt/H-mordenite

Cited by 35 publications

References 55 publications

Alkane isomerization over sulfated zirconia solid acid system

Alkane isomerization over sulfated zirconia solid acid system

Zeolites as Catalysts for Fuels Refining after Indirect Liquefaction Processes

Perengkahan n-Butana Menggunakan Katalis Nanopartikel Zeolit Alam Klaten

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