Ethane to Aromatic Hydrocarbons: Past, Present, Future

Hagen, Anke; Roessner, F.

doi:10.1081/cr-100101952

Cited by 183 publications

(127 citation statements)

References 110 publications

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“…Thus, the enhancement of alkane conversion towards the formation of aromatic molecules on Zn-modified zeolites could be achieved. So, the effect of Zn, which earlier was attributed either to the dehydrogenation ability of the loaded metal [3,17] or its ability to afford the recombinative desorption of H atoms, [2,11,13] is shown to be the direct influence of Zn on the activation of alkane CÀH bonds by the catalyst's Brønsted acid sites.…”

mentioning

confidence: 91%

“…[1,2,[5][6][7][8][9][10][11][12][13][14][15][16] On the one hand, there is agreement on the bifunctional nature of these catalysts, where the metal species are responsible for the dehydrogenation of alkanes, while the Brønsted acid sites are involved in the oligo-A C H T U N G T R E N N U N G merization and cyclization of olefins. [3,17] On the other hand, it has been claimed that the activation and cleavage of CÀH bonds of alkanes occurs predominantly at the Brønsted acid sites. [2,11,13] Ga or Zn act as "portholes" and catalyze the recombinative desorption of H atoms, formed from acid-catalyzed CÀH bond cleavage, as dihydrogen (H 2 ).…”

Section: Introductionmentioning

confidence: 98%

“…In both cases, the activation of the alkane by the Brønsted acid sites is assumed to be independent of metal species present in zeolites. [2,3,11,13,17] A simple reaction of hydrogen exchange between the acid sites of solid catalysts and alkane molecules, which usually precedes the chemical transformation of alkanes by the catalysts, [18] is often used to characterize the activation of alkanes and the acidity of the catalysts. [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] Valuable information on the peculiarities of alkane molecule activation has been obtained by monitoring H/D exchange for alkanes with 1 H MAS NMR in situ.…”

Section: Introductionmentioning

confidence: 99%

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Significant Influence of Zn on Activation of the C‐H Bonds of Small Alkanes by Brønsted Acid Sites of Zeolite

et al. 2008

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Herein, we analyze earlier obtained and new data about peculiarities of the H/D hydrogen exchange of small C(1)-n-C(4) alkanes on Zn-modified high-silica zeolites ZSM-5 and BEA in comparison with the exchange for corresponding purely acidic forms of these zeolites. This allows us to identify an evident promoting effect of Zn on the activation of C-H bonds of alkanes by zeolite Brønsted sites. The effect of Zn is demonstrated by observing the regioselectivity of the H/D exchange for propane and n-butane as well as by the increase in the rate and a decrease in the apparent activation energy of the exchange for all C(1)-n-C(4) alkanes upon modification of zeolites with Zn. The influence of Zn on alkane activation has been rationalized by dissociative adsorption of alkanes on Zn oxide species inside zeolite pores, which precedes the interaction of alkane with Brønsted acid sites.

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mentioning

confidence: 91%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Significant Influence of Zn on Activation of the C‐H Bonds of Small Alkanes by Brønsted Acid Sites of Zeolite

et al. 2008

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“…It was well known that addition of promoters like Zn or Ga to HZSM-5 zeolite could effectively improve propane aromatization activity [7,11,29]. In the case of 1-hexene as feed, the main role of Zn exhibits as cyclization.…”

Section: Roles Of Zn and Mg Additionmentioning

confidence: 99%

“…Particular research efforts have been directed at Zn or Ga modified zeolites since they showed higher aromatization product selectivity than the parent zeolites [3,8,10,28,29]. Dual roles of Zn as dehydrogenation and aromatization were revealed and put forward.…”

Section: Roles Of Zn and Mg Additionmentioning

confidence: 99%

Effects of Zinc and Magnesium Addition to ZSM-5 on the Catalytic Performances in 1-hexene Aromatization Reaction

Liu

Zhu

et al. 2011

Catal Lett

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Effects of Zn and Mg addition on the catalytic performances of ZSM-5 in 1-hexene aromatization and isomerization were investigated. NH 3 -TPD and Pyridine-IR spectra revealed that the addition of Zn could increase the Lewis acidity amount of the support. And the catalytic aromatization activity was improved. Introduction of Mg resulted in a decrease of total acidity, especially for Br/ nsted acid sites which was beneficial for the high iso-paraffin and liquid product yield. The optimal modification way on ZSM-5 was obtained as addition of Mg with successive Zn introduction which may lead to the presence of Zn species inside of the zeolite channel evidenced by XPS results. The close proximity of Zn species to Br/nsted acid sites may enhance the synergy effect between them in the aromatization reaction. The optimized Zn-Mg/HZSM-5 sample also exhibited good catalytic performance when using FCC gasoline as reactant.

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Dehydrocyclization—Heterogeneous

Paál¹

2010

Encyclopedia of Catalysis

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The formation of aromatic rings from alkanes such as hexane, heptane, octane, and so on (aromatization or dehydrocyclization) on oxide catalysts: chromia, lanthana, metals, such as platinum, palladium, and so on, and nonacidic (Na‐ or Ba‐L zeolite) supports is a “monofunctional” route, catalyzed by the active ingredient itself. A bifunctional route prevails in naphtha reforming (platforming) over Pt on acidic supports (eg, alumina). Interactions of Pt with acidic or alkaline support can be important for aromatization. The metallic function can also catalyze the formation of five‐membered ring(s): C5‐cyclization. The effect of added metallic components resulting in bimetallic catalysts (such as PtRe, PtSn, and so on) as well as the effect of nonmetallic components (Cl, S, C, H) is discussed. Aromatization requiring skeletal rearrangement (eg, of alkylpentane feeds) can also take place. Cyclic hydrocarbons may undergo ring enlargement and ring contraction. The same catalyst may promote the formation of a second ring in alkylcyclopentanes. The buildup of aromatic rings is also possible from smaller molecules (ethane, propane, butane) by dehydrocyclodimerization over bifunctional catalysts, such as ZSM 5 zeolites containing Pt, Zn, but first of all Ga (eg, in the CYCLAR process). Aromatics can be produced even from methane (Mo carbide‐ZSM‐5 or Pd‐Co catalysts).

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Ethane to Aromatic Hydrocarbons: Past, Present, Future

Cited by 183 publications

References 110 publications

Significant Influence of Zn on Activation of the C‐H Bonds of Small Alkanes by Brønsted Acid Sites of Zeolite

Significant Influence of Zn on Activation of the C‐H Bonds of Small Alkanes by Brønsted Acid Sites of Zeolite

Effects of Zinc and Magnesium Addition to ZSM-5 on the Catalytic Performances in 1-hexene Aromatization Reaction

Dehydrocyclization—Heterogeneous

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