Transformation of LPG into Aromatic Hydrocarbons and Hydrogen over Zeolite Catalysts

Giannetto, G.; Monque, R.; Galiasso, R.

doi:10.1080/01614949408013926

Cited by 186 publications

(85 citation statements)

References 43 publications

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“…[5][6][7] These isotopic results suggest that propane aromatization occurs on H-ZSM5 by a complex reaction sequence, with a first step consisting of propane dehydrogenation to propene or propane cracking to ethene and methane (confirmed by reactions of propene/propane-2-13 C mixtures). Reactions of propane-2-13 C show that chain growth on H-ZSM5 involves rapid alkene oligomerization/cracking cycles.…”

Section: Discussionmentioning

confidence: 91%

“…Propane reaction pathways have been extensively discussed in the literature primarily on the basis of observed effects of catalyst composition on reaction rate and selectivity. [5][6][7][8][9][10][11][12] We have obtained more direct evidence for the sequence of steps 13 C distribution in ethene formed from propane-2-…”

mentioning

confidence: 98%

“…Light alkane chain growth pathways on zeolitic acids involve dehydrogenation, dimerization, cyclization, and aromatization steps, which proceed in parallel with acid-catalyzed and thermal cracking steps. [5][6][7] Numerous studies have addressed the mechanism of chain growth and cyclization during light alkane reactions with primary emphasis on measuring the effect of catalyst composition on reaction rate and selectivity. [5][6][7][8][9][10][11][12] Here, we report direct evidence for the mechanistic sequence and for reactive intermediates using 13 C isotopic tracer and exchange methods.…”

Section: Introductionmentioning

confidence: 99%

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Isotopic Tracer Studies of Propane Reactions on H−ZSM5 Zeolite

Biscardi

Iglesia

1998

J. Phys. Chem. B

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Reactions of 13 C-labeled alkanes show that chain growth and cyclization reactions on H-ZSM5 require the initial formation of the corresponding alkene and its extensive participation in rapid oligomerization/ -scission reactions before cyclization occurs. The role of alkene intermediates was established by the initial formation of predominantly unlabeled products from mixtures of propene and propane-2-13 C reactants. Aromatic products of propane-2-13 C reactions on H-ZSM5 contain similar fractions of 13 C-atoms and binomial isotopomer distributions. Sequential formation, rapid intramolecular isomerization, and -scission reactions of long surface chains must occur during each aromatization turnover in order to form such binomial 13 C isotopomer distributions.

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Section: Discussionmentioning

confidence: 91%

mentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Isotopic Tracer Studies of Propane Reactions on H−ZSM5 Zeolite

Biscardi

Iglesia

1998

J. Phys. Chem. B

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“…Likewise, gallium modified HZSM-5 catalyst also had a capability of considerably elevating the selectivity towards aromatics [13][14][15][16], however, due to its high price, gallium was not appropriate for commercial application. In addition, zinc modified HZSM-5 catalyst was also widely reported in large numbers of papers [17][18][19][20][21][22][23][24], but the activity of the catalyst was unable to last long.…”

Section: Introductionmentioning

confidence: 99%

Effect of γ-alumina as active matrix added to HZSM-5 catalyst on the aromatization of methanol

Chen

Zhang

et al. 2015

Appl Petrochem Res

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HZSM-5-based catalyst is a recognized catalyst which is particularly selective towards the formations of aromatics in the methanol reaction. However, studies on HZSM-5-based catalyst were mainly focused on the addition of metallic or/and nonmetallic element. Quite few studies have reported the effect of active matrix such as calumina on the aromatization of methanol. In this study, calumina was introduced into HZSM-5-based catalyst for the purpose of investigating the effect of c-alumina in methanol to aromatics reaction. The catalysts were characterized by X-ray diffraction, Temperature-programmed Desorption of NH 3 (NH 3 -TPD), Pyridine adsorption FT-IR diffuse reflection spectroscopy and adsorption-desorption measurements of nitrogen, respectively. Characterizations showed that the introduction of c-alumina increased the amount of mesopores and acid sites in the catalyst. The experimental mainly includes two parts. Firstly, separate reaction performances over the catalyst with/without calumina and c-alumina showed that c-alumina could significantly promote the formations of aromatics. However, c-alumina alone could merely convert methanol to dimethyl ether with a minor quantity of gaseous hydrocarbons. Acid properties showed that the introduction of c-alumina increased the percentage of Lewis acid on catalyst surface and enhanced acid strength, as a result, promoted the production of active intermediates which was essential for aromatic formation. The rise of aromatics selectivity might be caused by the combined effect of acid site density and acid strength. Follow-up work was mainly focused on the effect of the loading amount and loading order of the catalyst with c-alumina. Results indicated that the total aromatic yield increased gradually with the increasing amount of catalyst with c-alumina regardless of the loading order of the catalyst with c-alumina. Gasoline compositions showed that the increased aromatics were at the expense of paraffins, olefins, and naphthenes. Besides, all single aromatic hydrocarbons increased gradually with the increasing amount of catalyst with c-alumina. And the aromatics had a larger variation change when methanol first passed through the catalyst with c-alumina.

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“…Of these additives, MTBE has been the most commonly used; therefore, great efforts have been made to maximize its production. The most frequently utilized process for the commercial production of MTBE is the conversion of iso-butene and methanol on acid catalysts (Naber, 1994).Thus, the manufacture of MTBE is strongly dependent on iso-butene production, which is possible by the following processes: (a) typical n -butene isomerization using acid catalysts and mainly acid zeolites (Butler and Nicolaides, 1993;Cheng and Ponec, 1994;Seo et al, 1997); (b) conversion of n-butane to iso-butene, involving dehydrogenation/isomerization steps on bifunctional catalysts (Giannetto et al, 1994), with a strongly dehydrogenation metallic function associated with strong acid sites such as those found in H/zeolites. This process, though not sufficiently studied, is the most attractive as it allows production of iso-butene in only one step.…”

Section: Introductionmentioning

confidence: 99%

Conversion of n-Butane to iso-Butene on Gallium/HZSM-5 Catalysts

Gheno

Urquieta‐González

2002

Braz. J. Chem. Eng.

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-The conversion of n -butane to iso-butene on gallium/HZSM-5 catalysts at 350 º C and WHSV=2.5h8 -1 was studied. The catalysts were prepared by ion exchange from a Ga(NO3) 2 solution and further submitted to calcination in air at 530 º C. TEM analysis with an EDAX detector and TPR-H 2 data showed that after calcination the Ga species were present mainly as Ga 2 O 3 , which are reduced to Ga 2 O at temperatures near 610 º C. The specific acid activity (SAA) of the catalysts increased with the increase in aluminum content in the zeolite, and for a fixed Si/Al ratio, the SAA increased with Ga content. Values for specific hydro/dehydrogenation activity (SH/DHA) were significantly higher than those for SAA, indicating that the catalytic process is controlled by the kinetics on acid sites. Moreover, the production of iso-butene with a selectivity higher than 25% was a evidence that in gallium/HZSM-5-based catalysts the rate of the hydrogenation reaction is lower than that of the dehydrogenation reaction; this behavior confirmed the dehydrogenation nature of gallium species, thereby showing great promise for iso-butene production.

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Transformation of LPG into Aromatic Hydrocarbons and Hydrogen over Zeolite Catalysts

Cited by 186 publications

References 43 publications

Isotopic Tracer Studies of Propane Reactions on H−ZSM5 Zeolite

Isotopic Tracer Studies of Propane Reactions on H−ZSM5 Zeolite

Effect of γ-alumina as active matrix added to HZSM-5 catalyst on the aromatization of methanol

Conversion of n-Butane to iso-Butene on Gallium/HZSM-5 Catalysts

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