A New Reaction That Occurs in the Hydrocracking of Certain Aromatic Hydrocarbons

Sullivan, R. F.; Egan, Clark J.; Langlois, G. E.; Sieg, R.P.

doi:10.1021/ja01466a036

Cited by 162 publications

(141 citation statements)

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“…Hence, generation of such species has been forbidden during network generation. To allow the paring reaction on cycloalkanes (Sullivan et al, 1961;Weitkamp et al, 1984;Souverijns et al, 1996), tetrabranched naphthenes and aromatics were included in the network, however. This a posteriori relumping allows reducing drastically the number of species to follow during the simulations.…”

Section: Families Consideredmentioning

confidence: 99%

Reduction of Single Event Kinetic Models by Rigorous Relumping: Application to Catalytic Reforming

Cochegrue

Gauthier

Verstraete

et al. 2011

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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Résumé -Réduction de modèles cinétiques basée sur les événements constitutifs à l'aide d'un regroupement rigoureux : application au reformage catalytique -La modélisation des procédés de raffinage utilisant des catalyseurs bifonctionnels métal-acide fait intervenir un nombre exponentiellement croissant d'espèces et de réactions qui peut rapidement dépasser plusieurs milliers pour des charges industrielles complexes. Lors de la réalisation d'un modèle de procédé, l'utilisation de modèles cinétiques de regroupement a priori par familles chimiques ne satisfait plus les besoins actuels de simulation détail-lée, de prédictivité et d'extrapolabilité. À cause du grand nombre d'étapes élémentaires impliquées dans la catalyse bifonctionnelle, il est déraisonnable de vouloir construire à la main un réseau cinétique détaillé d'une telle ampleur. La génération informatique du réseau réactionnel à partir de règles simples propose une solution élégante dans un tel cas. Malgré cela, l'établissement des équations cinétiques et leur résolu-tion reste difficile, essentiellement à cause du manque de détail analytique demandé par un modèle détaillé. Néanmoins, pour plusieurs procédés de raffinage, des hypothèses raisonnables concernant les équilibres entre espèces permettent d'effectuer un regroupement a posteriori des espèces, réduisant de cette manière la taille du réseau réactionnel tout en maintenant un réseau cinétique entre familles chimiques qui est strictement équivalent au réseau détaillé. Nous présentons ici les outils de génération de réseau et la méthode de regroupement a posteriori associés à la méthode de modélisation cinétique par événements constitutifs. Cette approche de regroupement a posteriori est illustrée et appliquée à la modélisation cinétique des réactions de reformage catalytique. Abstract

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Section: Families Consideredmentioning

confidence: 99%

Reduction of Single Event Kinetic Models by Rigorous Relumping: Application to Catalytic Reforming

Cochegrue

Gauthier

Verstraete

et al. 2011

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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“…[5] This result gave rise to scepticism as to whether methane-involved aromatization occurred at all. [5] Herein we report that transfer of isotopically 13 C-labeled atoms from methane into the aromatic products does occur to a high degree during the co-conversion of methane and propane on the Zn-modified high-silica zeolite BEA. We have identified the nature of the intermediates formed during the activation of methane and established how the conversion of methane into aromatic compounds occurs.…”

mentioning

confidence: 94%

“…[2-4] However, previous experiments in which 13 C-labeled methane was used did not confirm the presence of the 13 C-labeled atoms from the methane in the aromatization products. [5] This result gave rise to scepticism as to whether methane-involved aromatization occurred at all.…”

mentioning

confidence: 99%

Understanding Methane Aromatization on a Zn‐Modified High‐Silica Zeolite

et al. 2008

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It takes two: A high level of conversion of 13C atoms of methane into the products of methane/propane coaromatization on zeolite Zn/H‐BEA has been demonstrated by 13C solid‐state NMR spectroscopic analysis and GC‐MS. The isotope‐labeling experiments show the mechanism consists of the methylation of aromatic compounds formed from the propane followed by ring‐expansion/contraction (see scheme).

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“…Paring reaction was first proposed by Sullivan et al [19] in the early sixties for the hydrocraking of hexamethylbenzene over a NiS-Al 2 O 3 -SiO 2 catalyst. It involves a sequence of reactions to apparently pare methyl groups from polymethylated aromatics.…”

Section: Introductionmentioning

confidence: 99%

The effect of Y-zeolite acidity on m-xylene transformation reactions

Al-Khattaf¹,

Iliyas²,

Al-Amer³

et al. 2005

Journal of Molecular Catalysis A: Chemical

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m-Xylene transformation has been studied on as-prepared H-Y and a series of dealuminated Y zeolite catalysts. The conversion of m-xylene was found to increase initially with acidity, however, decreases subsequently. It has been proposed that the high concentration of acid sites in the H-Y catalyst increases paring reaction, in addition to the well-known isomerization and disproportionation pathways. A significant decrease was observed with respect to disproportionation/paring (D/Pa) ratio versus reaction temperature. This indicates that higher activation energy is required for paring as compared to disproportionation reaction. The p-xylene/o-xylene (P/O) was established to be independent of zeolite acidity. A higher coke deposition was found for the transformation of m-xylene over the parent H-Y as compared to the highly dealuminated USY zeolite. The formation of benzene and C 2 -C 4 gases were found to be proportional to zeolite acid concentration.Keywords: m-Xylene transformation, Y zeolite, isomerization, disproportionation, paring reaction. * Corresponding author. Tel.: +966-3-860-1429; Fax: +966-3-860-4234 E-mail address: skhattaf@kfupm.edu.sa 2 IntroductionXylenes are important starting materials for some industrial processes like the production of synthetic fibers, plasticizers and resins. The major sources of these aromatic hydrocarbons are the reforming and pyrolysis gasoline, which have a higher ratio of low-valued m-xylene. A convenient way to upgrade the low-valued m-xylene consists of its transformation to o-and p-xylene. In this context, the transformation of m-xylene has been studied over different types of zeolite catalysts [1][2][3][4][5][6][7][8].There is interest in ultrastable Y-type zeolites for m-xylene transformation, partly because of their increased chemical and thermal stability, with respect to other zeolites. Y-zeolite is made ultrastable by the removal of aluminum from the framework. The dealumination can be accomplished through the use of steam [9], acid leaching [10], or by chemical treatment with hexaflourosilicate or silicon tetrachloride [11][12][13]. However, the most common procedure is hydrothermal treatment at elevated temperatures under controlled atmosphere (steaming). The resulting material, USY (ultrastable Y) zeolites, being modified in the framework Si/Al ratio, structure and acidity, usually exhibits improved reactivity, selectivity and coking behavior for a catalytic reaction, which is of great interest to the petroleum industry. Several studies have been conducted on the effect of Y-zeolite acid properties on isomerization and disproportionation of m-xylene reactions [1,5,7]. However, studies correlating the intrinsic properties of Y-zeolite to other reaction pathways, apart from isomerization and disproportionation are somewhat limited. With this in mind, the present work reports the effect of acid properties of Y-zeolite on products selectivity and various reaction pathways during m-xylene transformation in a fluidizedbed reactor. As prepared H-Y zeolite ...

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A New Reaction That Occurs in the Hydrocracking of Certain Aromatic Hydrocarbons

Cited by 162 publications

References 0 publications

Reduction of Single Event Kinetic Models by Rigorous Relumping: Application to Catalytic Reforming

Reduction of Single Event Kinetic Models by Rigorous Relumping: Application to Catalytic Reforming

Understanding Methane Aromatization on a Zn‐Modified High‐Silica Zeolite

The effect of Y-zeolite acidity on m-xylene transformation reactions

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