Synthesis of nanosized HZSM-5 zeolites isomorphously substituted by gallium and their catalytic performance in the aromatization

Su, Xiaofang; Wang, Gaoliang; Bai, Xuefeng; Wu, Wei; Xiao, Linfei; Fang, Yujun; Zhang, Jianwei

doi:10.1016/j.cej.2016.02.088

Cited by 105 publications

(68 citation statements)

References 38 publications

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“…NiMo/2GaY-ASA-A exhibits the highest 3,4'-DMDBT and 4,4'DMDBT selectivity and the lowest trimethyl-and tetramethyl-DBTss electivity.A sm entioned previously,c onsidering the great similarity in chemical behavior between gallium and aluminum, Ga-OH-Si sites formed at the mesopore surface of the HUSY zeolite, and some Al-O(H)-Si sites were substituted by Ga-O(H)-Si/Al-O(H)-Ga sites ( Figure 2);A l-O(H)-Si sites were also formed at the interface of different components of the catalyst supports. [51,52] Thus, some Lewis acid sites, together with some weak and strong Brønsted acid sites, were transformed into medium Brønsted acid sites ( Table 2). [53] Although the gallium-modified zeolites have lower acid strength than the original zeolites, it is easier for gallium-modified zeolites to donate Brønsted protons.…”

Section: Effect Of Gallium Modification On the Catalystperformance Ofmentioning

confidence: 99%

Gallium Modified HUSY Zeolite as an Effective Co‐support for NiMo Hydrodesulfurization Catalyst and the Catalyst's High Isomerization Selectivity

Zhou

Wei

et al. 2017

Chemistry A European J

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The effects of metal-modified acidic co-supports on the hydrodesulfurization (HDS) activity and isomerization selectivity of highly refractory organosulfur compounds such as 4,6-dimethyldibenzothiophene have been investigated. Y zeolite crystals with high Si/Al ratios and small crystallite sizes were successfully synthesized by a new hydrothermal synthesis approach. The synthesized Y zeolite crystals were ion-exchanged and stabilized. The prepared samples were then modified with different gallium contents using an impregnation method to adjust their acidity properties, and these modified samples were used as co-supports for NiMo sulfide HDS catalysts. The catalyst containing 10 wt.% zeolite Y modified by 2 wt.% gallium (NiMo/2GaY-ASA-A) exhibited the highest HDS activity, with 4,6-dimethyldibenzothiophene (4,6-DMDBT) conversion nearly double the rate of the catalyst without zeolite at 563 K, 4.0 MPa and liquid hourly space velocity (LHSV) of 40 h . NiMo/2GaY-ASA-A also exhibited superior isomerization ability, with 3,4'-DMBP, 4,4'DMBP, and 3,6-DMDBT as the main products, indicating that the isomerization pathway was the main reaction route over NiMo/2GaY-ASA-A. The superior catalytic performance is related to the synergistic effect of the proper amount of medium and strong Brønsted acid sites. The compounds 3,6-DMDBT and 3,7-DMDBT (isomers of 4,6-DMDBT) and 3,4,6-TMDBT and tetra-methyl-DBT (transmethyl products) were detected simultaneously in the HDS product of 4,6-DMDBT for the first time over NiMo/GaY-ASA-A catalysts. Finally, a new reaction network over NiMo/2GaY-ASA-A was proposed.

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Section: Effect Of Gallium Modification On the Catalystperformance Ofmentioning

confidence: 99%

Gallium Modified HUSY Zeolite as an Effective Co‐support for NiMo Hydrodesulfurization Catalyst and the Catalyst's High Isomerization Selectivity

Zhou

Wei

et al. 2017

Chemistry A European J

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“…1220 cm -1 and 1100 cm -1 , correspond to SiO 4 asymmetrical stretching vibration and asymmetrical stretching vibration of the T-O-T structure (tetrahedral-octahedral tetrahedra), while at approx. 800, 560, and 460 cm -1 correspond to the T-O-T deformation tensile vibration, respectively [14]. ZnO can not be identified because it has spectral bands at about 460 cm -1 and 545 cm -1 [15] overlapping with Mo-O specific bands which also have 560 cm -1 or Si-O-Si spectral bands 466 cm -1 .…”

Section: Results and Discussion Catalyst Characterizationmentioning

confidence: 99%

Hydrodesulphurization of Thiophenes over CoMoRe/ ZSM 5gama-Al2O3 Catalyst

Doukeh¹,

Bombos²,

Moldovan³

et al. 2018

Rev. Chim.

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The hydrodesulphurization (HDS) of thiophenes was performed on metallic catalyst CoMoRe/ZSM5-gAl2O3. Experiments were carried out on a fixed bed catalytic reactor at 175-300�C, 30-60 atm, thiophene volume hourly space velocities of 1h-1- 4h-1 and molar ratio hydrogen/thiophene of 60/1. Texture features like specific surface area, the pore volume and the average pore diameter decrease after catalyst sulfurization. The thiophenes conversion on CoMoRe/gAl2O3-Zn-HZSM 5 catalyst differs with the nature of the studied thiophenes.

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“…Su et al. [8], in an interesting work invented a method that the seed-induced in-situ hydrothermal synthesis of nano sized HZSM-5 zeolites that are partially or completely isomorphously substituted by gallium, denoted as GaAlHNZ5 and Ga/HNZ5, in the same order. In comparison to the traditional impregnation method, this technique develops conditions so that it could decrease a lot of organic templates in the synthesis process and properly inhibit the loss of gallium species.…”

Section: Galliummentioning

confidence: 99%

“…Whereas the first three steps are done on the Bronsted acid sites, the hydrogen transfer mechanism, as the lowest reaction rate (the rate-controlling step), is handled on the Lewis acid sites. Owning to that, the synergistic between the two kinds of acid sites makes an impact positively on the aromatization reaction rate [8].…”

Section: Introductionmentioning

confidence: 99%

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An overview on the effects of metal promoters and acidity of ZSM-5 in performance of the aromatization of liquid hydrocarbons

Sharifi¹,

Halladj

Royaee³

2020

Reviews on Advanced Materials Science

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AbstractThe use of liquid hydrocarbons, such as FCC naphtha, having olefin components makes an adverse impact on our environment. To deal with the problem, one could convert those lethal components, including olefin and paraffin structures, into aromatic compounds under aromatization processes. To this aim, generally zeolite catalysts, especially the ZSM-5 sample, are utilized to facilitate the aromatization processes. According to the general knowledge in this field, such parameters as the metal promoter and the amount of acidity of catalyst affect the performance of zeolite catalysts. In this paper, with the aim of getting acquainted with the conditions to form the desirable products under the best performance of the zeolites, numerous published papers were reviewed.

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Synthesis of nanosized HZSM-5 zeolites isomorphously substituted by gallium and their catalytic performance in the aromatization

Cited by 105 publications

References 38 publications

Gallium Modified HUSY Zeolite as an Effective Co‐support for NiMo Hydrodesulfurization Catalyst and the Catalyst's High Isomerization Selectivity

Gallium Modified HUSY Zeolite as an Effective Co‐support for NiMo Hydrodesulfurization Catalyst and the Catalyst's High Isomerization Selectivity

Hydrodesulphurization of Thiophenes over CoMoRe/ ZSM 5gama-Al2O3 Catalyst

An overview on the effects of metal promoters and acidity of ZSM-5 in performance of the aromatization of liquid hydrocarbons

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