Kinetics of toluene alkylation with methanol catalyzed by pure and hybridized HZSM-5 catalysts

Alabi, Wahab O.; Atanda, Luqman; Jermy, Rabindran; Al-Khattaf, S.

doi:10.1016/j.cej.2012.04.100

Cited by 73 publications

(33 citation statements)

References 43 publications

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“…[1][2][3] Studies showed that hierarchical porous ZSM-5 could overcome the limitation of micropores to achieve better catalytic performance. [1][2][3] Studies showed that hierarchical porous ZSM-5 could overcome the limitation of micropores to achieve better catalytic performance.…”

Section: Introductionmentioning

confidence: 99%

Promoting effects of MgO and Pd modification on the catalytic performance of hierarchical porous ZSM-5 for catalyzing benzene alkylation with methanol

Lyu

Cen

et al. 2015

RSC Adv.

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The effect of MgO and Pd modification on the catalytic performance of hierarchical porous ZSM-5 for benzene alkylation with methanol was investigated. The results indicated that the introduction of MgO could reduce the Brönsted acid sites which suppressed the side reaction of methanol to olefins and in turn effectively promoted the alkylation of benzene. However, the single modification of MgO could not completely suppress the formation of ethylbenzene and coke. Doping a small amount of Pd had a positive effect on inhibiting the generation of ethylbenzene and coke, which could be attributed to the hydrogenation of ethylene into ethane on Pd. The dual modified catalyst (MgO and Pd) exhibited high benzene conversion (56%) and xylene selectivity (39.1%), and the lowest ethylbenzene selectivity (0.13%) and coke content (0.4 wt%).

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Section: Introductionmentioning

confidence: 99%

Promoting effects of MgO and Pd modification on the catalytic performance of hierarchical porous ZSM-5 for catalyzing benzene alkylation with methanol

Lyu

Cen

et al. 2015

RSC Adv.

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“…The proton donors in zeolites are the Brønsted acid sites provided by the bridging OH linking Si to Al within the framework; Lewis sites are electron donors constituted by extra-framework Al [5]. Xylene isomerization, disproportionation, and dealkylation are catalyzed by Brønsted acid sites [6][7][8]. Disproportionation needs higher concentrations of acid sites [9] and the strength of these sites follows the trend: isomerization < dealkylation < disproportionation [10,11].…”

Section: Introductionmentioning

confidence: 99%

Xylene Isomerization in the Liquid Phase Using Large‐Pore Zeolites

Gonçalves

Rodrigues

2015

Chem Eng & Technol

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Three large-pore zeolites, Beta with Si/Al ratios of 25 and 35 and Mordenite with an Si/Al ratio of 30, were studied in the conversion of o-xylene at 493 K. Maximum conversion was achieved by the catalyst with the highest Si/Al ratio due to faster diffusion of the isomer inside the zeolite channels because of the lower acidity of the solid even with larger crystal size. A kinetic study was then carried out over this catalyst between 473 and 513 K in a batch reactor in the liquid phase. The activation energies obtained do not indicate the presence of diffusional constraints towards any isomer. Finally, the kinetic model obtained was simulated in a fixed-bed reactor and compared to ZSM-5 in the temperature range from 493 to 533 K. An increment in p-xylene production of 20 % on average was obtained.

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“…Therefore, alkanes in the products may be generated from the hydrogenation of toluene. By co-feeding methanol, various methylation reactions of reactants or intermediates may occur as follows: (1) methylation of cresol into xylenols and methylanisole [31]; (2) methylation of benzene with methanol to give toluene [36]; (3) methylation of toluene producing xylenes (o-, m-and p-xylene) [30,[37][38][39]; and(4) polyalkylated benzenes and polyalkylated phenols from the methylation of xylenes and xylenols with methanol, respectively.…”

Section: 6mentioning

confidence: 99%

“…This reaction could be catalyzed by various parent zeolites, such as HZSM-5, MOR, MCM-22, etc., with a high selectivity of p-xylene up to 90%. However, the maximum conversion of toluene in these processes was generally below 50.0% [30]. Meanwhile, the alkylation of m-cresol with methanol was observed to produce xylenols [31], which also could be converted into xylenes via HDO [32].…”

Section: Introductionmentioning

confidence: 99%

High Selectively Catalytic Conversion of Lignin-Based Phenols into para-/m-Xylene over Pt/HZSM-5

2016

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Abstract:High selectively catalytic conversion of lignin-based phenols (m-cresol, p-cresol, and guaiacol) into para-/m-xylene was performed over Pt/HZSM-5 through hydrodeoxygenation and in situ methylation with methanol. It is found that the p-/m-xylene selectivity is uniformly higher than 21%, and even increase up to 33.5% for m-cresol (with phenols/methanol molar ratio of 1/8). The improved p-/m-xylene selectivity in presence of methanol is attributed to the combined reaction pathways: methylation of m-cresol into xylenols followed by HDO into p-/m-xylene, and HDO of m-cresol into toluene followed by methylation into p-/m-xylene. Comparison of the product distribution over a series of catalysts indicates that both metals and supporters have distinct effect on the p-/m-xylene selectivity.

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Kinetics of toluene alkylation with methanol catalyzed by pure and hybridized HZSM-5 catalysts

Cited by 73 publications

References 43 publications

Promoting effects of MgO and Pd modification on the catalytic performance of hierarchical porous ZSM-5 for catalyzing benzene alkylation with methanol

Promoting effects of MgO and Pd modification on the catalytic performance of hierarchical porous ZSM-5 for catalyzing benzene alkylation with methanol

Xylene Isomerization in the Liquid Phase Using Large‐Pore Zeolites

High Selectively Catalytic Conversion of Lignin-Based Phenols into para-/m-Xylene over Pt/HZSM-5

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