Catalytic Properties of Synthetic Mordenite in Isomerization, Hydrogenation, and Hydroisomerization of Hydrocarbons

Миначев, Х. М.; Garanin, V. I.; Isakova, T. A.; Харламов, В. В.; Bogomolov, V. I.

doi:10.1021/ba-1971-0102.ch076

Cited by 30 publications

(20 citation statements)

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“…11 The mordenite structure is, however, stable to acid leaching, so almost all of the aluminum may be removed in this manner to make an almost purely siliceous mordenite. 12 The unit cell of mordenite has the dimensions aϭ18.13 Å, bϭ20.49 Å, cϭ7.52 Å. Two types of pores are present in mordenite; ͑i͒ the main channel runs parallel to the c axis and has the dimensions 6.7 Åϫ7.0 Å ͑circumscribed by 12-membered oxygen rings͒; ͑ii͒ smaller channels along the b direction with cross section 2.6 Åϫ5.7 Å ͑circumscribed by 8-membered oxygen rings͒.…”

Section: Mordenite Structurementioning

confidence: 99%

Adsorption and energetics of xenon in mordenite: A Monte Carlo simulation study

Nivarthi

Tassel

Davis

et al. 1995

The Journal of Chemical Physics

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Grand canonical Monte Carlo (GCMC) simulations were used to calculate energy contour maps, isodensity surfaces and adsorption isotherms of xenon in purely siliceous mordenite at 300 K using previously published potential parameters. Then, in order to understand the effect of aluminum content, Al-containing mordenites were modeled by adding the appropriate negative charge to each of the oxygen atoms in the mordenite framework and by inserting Na+ ions at fixed extra-framework positions previously identified from x-ray crystallographic data. GCMC simulations were again performed using these structure models. Both main channel and sidepocket xenon adsorption were observed in all mordenite structures. The sidepockets were found to be only singly occupied whereas the main channel allowed multiple occupancy. Sidepocket xenon adsorption became more favorable when cations (and aluminum) were introduced. In the main channel, xenon adsorbed into localized sites that were distributed in an octahedral arrangement within each unit cell with two apices in front of opposing sidepockets. These sites remained at the same location over the entire range of loading (0–16 Xe/unit cell) and cation (and aluminum) content.

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Section: Mordenite Structurementioning

confidence: 99%

Adsorption and energetics of xenon in mordenite: A Monte Carlo simulation study

Nivarthi

Tassel

Davis

et al. 1995

The Journal of Chemical Physics

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“…They are intersected by another eight-membered channel (C) that runs along the a-axis. 1 The chemical formula for clinoptilolite is (Na,K) 6 [Al 6 Si 30 O 72 ]‚24H 2 O. 3 The negative charge of the clinoptilolite framework from tetrahedrally coordinated aluminum is balanced by Na and K. These cations can be exchanged to some extent by transition metal ions.…”

Section: Introductionmentioning

confidence: 99%

Electron Spin Resonance and Electron Spin Echo Modulation Studies on the Formation and Adsorbate Interactions of Ni(Ι) in Synthetic Clinoptilolite

et al. 1999

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Electron spin resonance (ESR) and electron spin echo modulation (ESEM) spectroscopies were used to study the formation of Ni(Ι) by various reduction methods and various adsorbate interactions of Ni(Ι) in synthetic clinoptilolite, in which Ni(ΙΙ) was ion-exchanged into extraframework sites of clinoptilolite. Thermal reduction by dehydration at 573 K shows a single species assigned to Ni(Ι) ions. Two isolated Ni(Ι) ions are observed after hydrogen reduction at 623 K. Adsorption of methanol on hydrogen-reduced NiNaK-Clino forms a Ni(Ι)-(CD 3 OH) n complex resulting from the interaction of methanol with one of the isolated Ni(Ι) ions. Adsorption of ammonia on hydrogen-reduced NiNaK-Clino produces a prominent Ni(Ι)-(ND 3 ) n complex by interaction with both Ni(Ι) ions. The 13 C hyperfine structure and ESEM analysis parameters after 13 CO adsorption indicate that Ni(Ι) interacts with one CO molecule and forms a Ni(Ι)-(CO) 1 complex. Two Ni-(Ι)-(C 2 D 4 ) n complexes are generated after adsorption of ethylene on dehydrated Ni(II)NaK-Clino and subsequent heating below 623 K. At higher temperature, these species disappear with the concomitant formation of two Ni(Ι)-(C 4 D 8 ) n complexes, indicating ethylene dimerization. 2 D ESEM confirms the coordination of Ni(Ι) with butene. Adsorption of NO on dehydrated Ni(II)NaK-Clino produces two Ni(Ι)-NO + complexes formed by transfer of the odd electron from NO to Ni(ΙΙ) ions. Along with two Ni(Ι)-NO + species, another species assigned to the NO radical is also observed in NiNaK-Clino after NO adsorption on Ni(II)NaKClino and NaK-Clino.

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“…Figures 2(f), (h), (i) also illustrate how A1, by changing the symmetry of the A1 sites, can become essentially invisible to the NMR experiment. A particularly active catalyst can be made by calcining an ammonium-exchanged mordenite at 500 ~ C to form a hydrogen mordenite [2,3 ]. Exchanging the cation does not alter the lattice structure of the mordenite and, hence, does not affect the 29Si or 27A1 NMR spectrum.…”

Section: Resultsmentioning

confidence: 99%

“…For mordenites, particularly active catalysts may be produced by acid-leaching decationation, or by calcining the ammonium-exchanged mordenites [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

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Magic angle spinning29Si and27Al NMR study of mordenite dealumination

Ripmeester

Majid

Hawkins

1983

Journal of Inclusion Phenomena

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Abstract. Magic angle spinning 29Si NMR presents a rapid qualitative method of assessing the degree of dealumination of sodium mordenite modified by acid leaching and heat treatment. A quantitative determination of the 29Si coordination sphere is hampered by the overlap of chemical shift ranges for Si-O-A1 and Si-O-H species. MAS 27A1 NMR indicates the presence of oetahedrally coordinated A1 in interstitial sites in all treated samples. On treating mordenite samples at high temperatures (~ 700 ~ C) much of the A1 becomes invisible to the NMR experiment because of its location in sites of low symmetry and large quadrupole coupling constant.

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Catalytic Properties of Synthetic Mordenite in Isomerization, Hydrogenation, and Hydroisomerization of Hydrocarbons

Cited by 30 publications

References 0 publications

Adsorption and energetics of xenon in mordenite: A Monte Carlo simulation study

Adsorption and energetics of xenon in mordenite: A Monte Carlo simulation study

Electron Spin Resonance and Electron Spin Echo Modulation Studies on the Formation and Adsorbate Interactions of Ni(Ι) in Synthetic Clinoptilolite

Magic angle spinning29Si and27Al NMR study of mordenite dealumination

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