Transformation of ethylbenzene–m-xylene mixture on zeolites with different structures

Mihályi, R.M.; Klébert, Szilvia; Kollár, Márton; Mavrodinova, V.

doi:10.1007/s10934-014-9795-6

Cited by 5 publications

(3 citation statements)

References 28 publications

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“…In our previous contribution the catalytic performance of zeolite [Al]MCM-22 with intermediate pore structure was studied for the first time in the conversion of ethylbenzene-mxylene mixed feed [9]. The results reveal the promising properties of this catalyst for the selective elimination of EB from C 8 aromatics feed at admissible xylene loss, compared to that of the large-pore BEA and medium-pore ZSM-5 zeolites.…”

Section: Introductionmentioning

confidence: 97%

Transformation of ethylbenzene-m-xylene feed over MCM-22 zeolites with different acidities

Mihályi

Kollár

Klébert

et al. 2014

Applied Catalysis A: General

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Section: Introductionmentioning

confidence: 97%

Transformation of ethylbenzene-m-xylene feed over MCM-22 zeolites with different acidities

Mihályi

Kollár

Klébert

et al. 2014

Applied Catalysis A: General

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“…The diversity of the application of zeolites is wide and ranges from being used as a catalyst for the petrochemical industry to builder for laundry powders, odor control agents, and many other applications. − Many petrochemical processes strongly rely on the interaction and kinetic behavior of hydrocarbons inside a zeolite. − For example, xylene molecules diffusing along the zeolite pores can undergo isomerization, disproportionation, and transalkylation reactions . Thus, knowledge of the adsorption and diffusion behavior of hydrocarbons in the pores of zeolites is important for the understanding of the catalytic activity of the zeolite. − …”

Section: Introductionmentioning

confidence: 99%

Effects of Framework Flexibility on the Adsorption and Diffusion of Aromatics in MFI-Type Zeolites

et al. 2020

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We systematically study how the degree of framework flexibility affects the adsorption and diffusion of aromatics in MFI-type zeolites as computed by Monte Carlo simulations. It is observed that as the framework is more flexible, the zeolite structure is inherently changed. We have found that framework flexibility has a significant effect on the adsorption of aromatics in MFI-type zeolites, especially at high pressure. Framework flexibility allows the zeolite framework to accommodate to the presence of guest aromatic molecules. For very flexible zeolite frameworks, loadings up to two times larger than that in a rigid zeolite framework are obtained at a given pressure. We assessed the “flexible snapshot” method, which captures framework flexibility using independent snapshots of the framework. We have found that this method only works well when the loadings are low. This suggests that the effect of the guest molecules on the zeolite framework is important. Framework flexibility lowers the free-energy barriers between low energy states, increasing the rate of diffusion of aromatics in the straight channel of MFI-type zeolites for many orders of magnitude compared to a rigid zeolite framework. The simulations show that framework flexibility should not be neglected and that it significantly affects the diffusion and adsorption properties of aromatics in an MFI-type zeolite.

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“…However, the adsorption/isomerization process is usually preferred due to economic reasons. Despite the huge amount of related studies published during the past 20 years, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] the topic is still hot. The introduction of hierarchical HZSM-5 zeolites has enhanced this academic interest.…”

Section: Introductionmentioning

confidence: 99%

Kinetic modeling of the ethylbenzene/xylene isomerization reaction over HZSM‐5 zeolites revisited

Farahani

Falamaki

Alavi

2020

Int J of Chemical Kinetics

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In this article, a binderless dealuminated HZSM-5 zeolite (Si/Al = 41.4) was used as a catalyst for the isomerization of a mixture of ethylbenzene and xylene. The experimental results indicated that at low residence times the catalyst is effective to isomerize the ethylbenzene into xylenes. A comprehensive kinetic model considering chemisorption, surface chemical reactions, and diffusional processes was developed for this reaction. The intrinsic activation energy (71.99 kJ mol −1 ) for the surface reaction of ethylbenzene into m-xylene was calculated for the first time, and the corresponding intrinsic activation energies for o-xylene to m-xylene and m-xylene to p-xylene surface reactions were calculated to be 59.45 and 50.68 kJ mol −1 , respectively. Lower apparent values have been reported in the literature, and we rationalize that they correspond to multistep processes and intrinsically include a negative activation energy pertaining to chemisorption. The results also revealed that the ethylbenzene diffusion within the zeolite channels was four orders of magnitude smaller than p-xylene.

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Transformation of ethylbenzene–m-xylene mixture on zeolites with different structures

Cited by 5 publications

References 28 publications

Transformation of ethylbenzene-m-xylene feed over MCM-22 zeolites with different acidities

Transformation of ethylbenzene-m-xylene feed over MCM-22 zeolites with different acidities

Effects of Framework Flexibility on the Adsorption and Diffusion of Aromatics in MFI-Type Zeolites

Kinetic modeling of the ethylbenzene/xylene isomerization reaction over HZSM‐5 zeolites revisited

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