Ethylbenzene disproportionation and p -xylene selectivity enhancement in xylene isomerization using high crystallinity desilicated H-ZSM-5

Farshadi, Marjan; Falamaki, Cavus

doi:10.1016/j.cjche.2017.03.023

Cited by 23 publications

(9 citation statements)

References 32 publications

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“…Considering diffusion effects, and based on Equation(29), the apparent activation energy for this reaction is calculated to be 41.92 kJ mol −1 . This should be noted that our calculation resulted in near zero values for k9 and k 10 , showing that ethylbenzene prefers to convert into m-xylene directly, without o-xylene acting as an intermediate. Optimal values for the intrinsic and apparent activation energies of the surface chemical reactions…”

mentioning

confidence: 71%

“…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%

“…Dealumination, desilication, or their combination not only modify the micro/meso topology of the zeolite but also affect the number and nature of acid sites. [8][9][10] This impacts not only the diffusional transport coefficients of the reactants and products but also the intrinsic catalytic reaction rate constants and chemisorption/desorption characteristics of the acid sites. A complete kinetic model for the ethylbenzene/xylene mixtures isomerization reactions on HZSM-5 zeolite should embrace diffusion, adsorption/desorption, and intrinsic surface reactions phenomena concomitantly.…”

Section: Introductionmentioning

confidence: 99%

“…The introduction of hierarchical HZSM‐5 zeolites has enhanced this academic interest. Dealumination, desilication, or their combination not only modify the micro/meso topology of the zeolite but also affect the number and nature of acid sites 8–10 . This impacts not only the diffusional transport coefficients of the reactants and products but also the intrinsic catalytic reaction rate constants and chemisorption/desorption characteristics of the acid sites.…”

Section: Introductionmentioning

confidence: 99%

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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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mentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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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“…Furthermore, an interesting approach for acidity modification that is based on zeolite partial dealumination is plasma usage. Using this method, the dispersion of the metal is improved and the catalytic activity of the material is improved [21].…”

Section: Introductionmentioning

confidence: 99%

Modification Strategy of ZSM-5 Zeolite for Enhancing p-Xylene Selectivity in Toluene Disproportionation

Shehni¹,

Ghomsheh²

2022

Rev. Chim.

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In this study, modified zeolite was used to improve p-xylene selectivity in toluene dis-proportionation process. ZSM-5 zeolite was modified by introducing the phosphorus/Germanium loading and vacuum UV treatment from He+O2 microwave plasma treatment. Results showed that the ZSM-5 zeolite impregnated with Germanium and phosphorus have high p-xylene selectivity (up to 33 %). A sharp decrease in the acidity properties was achieved after phosphorus loading. By Germanium loading, selectivity increased but conversion did not change much. Also, the highest p-xylene selectivity (47 %) was obtained by P/Ge ZSM-5 with VUV treatment at the highest WHSV of 85 h-1.

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Synthesis of Hierarchical ZSM‐5 Submicron Spheres for Catalytic Cracking

et al. 2022

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A kind of hierarchical ZSM‐5 submicron sphere composed of zeolite nanocrystals was one‐pot synthesized with polydiene dimethyl ammonium chloride as template. X‐ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images show that the hierarchical ZSM‐5 submicron spheres have good crystallinity. N2 adsorption‐desorption isotherm and transmission electron microscopy (TEM) images indicate that the hierarchical ZSM‐5 submicron spheres have both micropores and mesopores. The results show that the hierarchical ZSM‐5 submicron spheres are formed by stacking nanocrystals, exhibits high crystallinity, microporous, mesoporous structures and higher catalytic activity in the catalytic cracking of 1, 3, 5‐triisopropylbenzene.

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Ethylbenzene disproportionation and p -xylene selectivity enhancement in xylene isomerization using high crystallinity desilicated H-ZSM-5

Cited by 23 publications

References 32 publications

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

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

Modification Strategy of ZSM-5 Zeolite for Enhancing p-Xylene Selectivity in Toluene Disproportionation

Synthesis of Hierarchical ZSM‐5 Submicron Spheres for Catalytic Cracking

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