Effect of the Si/Al ratio on the performance of hierarchical ZSM-5 zeolites for methanol aromatization

Gao, Yan; Zheng, Binghui; Wu, Guozhang; Ma, Fangwei; Liu, Chun‐Tao

doi:10.1039/c6ra17084f

Cited by 137 publications

(56 citation statements)

References 38 publications

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“…In agreement with the isotherms, samples with Si/Al=5 have larger mesoporous volume than the Si/Al=6 materials. These results are in agreement with previous studies where at lower Si/Al ratios the zeolitic mesopore volume increases [43].…”

Section: Fig 2 Ftir Spectra Of Synthesized Fauy Zeolitesupporting

confidence: 94%

Catalytic conversion of 5-hydroxymethylfurfural (5-HMF) over Pd-Ru/FAU zeolite catalysts

et al. 2021

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Section: Fig 2 Ftir Spectra Of Synthesized Fauy Zeolitesupporting

confidence: 94%

Catalytic conversion of 5-hydroxymethylfurfural (5-HMF) over Pd-Ru/FAU zeolite catalysts

et al. 2021

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“…It is well known that MTA is an acid catalytic reaction, enjoying from the synergetic effect between BAS and LAS. 56 Consistent with this proposal, the stronger BASs, the more active sites for the reaction. An increase in the amount of acid sites, however, improves the olefin cyclization reaction together with deep alkylation reaction of the aromatic products, leading to a subsequent increase in the formation of polyalkylaromatics in the reaction.…”

Section: Resultsmentioning

confidence: 53%

Highly Efficient Production of Benzene-Free Aromatics from Methanol over Low-Si/Al-Ratio Alkali-Modified Fe/Zn/HZSM-5

Ghanbari

Zangeneh

Rizi³

et al. 2018

ACS Omega

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Herein, the methanol conversion to aromatic hydrocarbons was studied over a new family of mesoporous low-silica HZSM-5 (Si/Al = 11) catalysts in a fixed-bed tubular reactor under ambient pressure at 375 °C, feeding with weight hourly space velocity of 2 h –1 . The catalysts were prepared in the absence and presence of Zn and Fe in both alkaline and neutral aqueous solutions, characterized by using X-ray diffraction, X-ray fluorescence, temperature programmed desorption of ammonia, N 2 adsorption/desorption, thermogravimetric analysis, Fourier-transform infrared, transmission electron microscopy (TEM), field emission scanning electron microscopy and FE-SEM/energy dispersive X-ray spectroscopy techniques. The [0.2Fe,0.3Zn]-alk-HZSM-5 catalyst exhibited novel selectivity for aromatics (>86 wt %), specifically for m and p -xylenes (44.7 wt %) alongside 0.1 wt % for benzene.

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“…Given the sample preparation conditions, it is unlikely that this decrease in surface area/pore volume is due to product retention within the zeolite pores. Alternately, this this physical change might be attributed to coking of the acidic zeolite catalyst during dehydration of methanol to DME, which is well documented; 28,29 however, TGA analysis in air of fresh and used catalysts showed no significant mass loss attributable to combustion of carbonaceous residues ( Figure S1). …”

Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 99%

Hydrogenation of CO₂ to Dimethyl Ether over Brønsted Acidic PdZn Catalysts

Bahruji

Armstrong

Esquius

et al. 2018

Ind. Eng. Chem. Res.

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Eschewing the common trend toward use of catalysts composed of Cu, it is reported that PdZn alloys are active for CO 2 hydrogenation to oxygenates. It is shown that enhanced CO 2 conversion is achievable through the introduction of Brønsted acid sites, which promote dehydration of methanol to dimethyl ether. We report that deposition of PdZn alloy nanoparticles onto the solid acid ZSM-5, via chemical vapor impregnation affords catalysts for the direct hydrogenation of CO 2 to DME. This catalyst shows dual functionality; catalyzing both CO 2 hydrogenation to methanol and its dehydration to dimethyl in a single catalyst bed, at temperatures of >270°C. A physically mixed bed comprising 5% Pd 15% Zn/TiO 2 and H-ZSM-5 shows a comparably high performance, affording a dimethyl ether synthesis rate of 546 mmol kg cat −1 h −1 at a reaction temperature of 270°C . ■ INTRODUCTIONMethanol is ubiquitous within the chemical industry, with global demand exceeding 57 Mt/annum. The majority of this is met through a two-step process whereby synthesis gas is produced via methane steam reforming and then reacted over a Cu/ZnO/Al 2 O 3 catalyst to prepare methanol. The energy consumption of this process is estimated to exceed 1 exajoule (1 × 10 18 J)/annum globally, with a significant carbon footprint (ca. 88 Mt GHG eq). 1 In line with political and social pressure to decrease society's dependence on fossil fuels, there is growing interest in producing methanol through more sustainable routes. One promising route is catalytic CO 2 hydrogenation. The process, however, is restricted by thermodynamic equilibrium; with the reverse water gas shift reaction (RWGS) dominating the reaction at high temperatures. Indeed, methanol is thermodynamically favored at lower temperatures. Unfortunately, because of the relatively low reactivity of CO 2 , high reaction temperatures and/or pressures are required for its activation. To maximize yields of valueadded products, it is important that CO 2 hydrogenation be carried out near equilibrium. One approach toward circumventing RWGS at elevated reaction temperatures is removal of the product, methanol, from the catalytic system. This can be achieved through dehydration to dimethyl ether (DME), typically over a solid acid catalyst. DME is a key feedstock for production of methylating agents for organic synthesis. 2 DME has also been identified as an environmentally friendly fuel, with low associated emissions of NO x , hydrocarbons, CO and SO x . 3 Through the methanol to gasoline (MTG) process, methanol is catalytically converted to yield an equilibrium mixture containing methanol, DME and water. This is then converted to hydrocarbons. 4 Being both exothermic and reversible, methanol dehydration is subject to thermodynamic limitation, though effectively not so under methanol synthesis conditions. 4 Integrating methanol dehydration into CO 2 hydrogenation reaction systems might increase hydrogenation yields, by intercepting the methanol through dehydration to DME, therefore shifting the reactio...

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Effect of the Si/Al ratio on the performance of hierarchical ZSM-5 zeolites for methanol aromatization

Abstract: A series of hierarchical ZSM-5 zeolites with different Si/Al ratios were successfully prepared using a seed-deduced method and the addition of organosilicone reagents into the medial synthesis system.

Cited by 137 publications

References 38 publications

Catalytic conversion of 5-hydroxymethylfurfural (5-HMF) over Pd-Ru/FAU zeolite catalysts

Catalytic conversion of 5-hydroxymethylfurfural (5-HMF) over Pd-Ru/FAU zeolite catalysts

Highly Efficient Production of Benzene-Free Aromatics from Methanol over Low-Si/Al-Ratio Alkali-Modified Fe/Zn/HZSM-5

Hydrogenation of CO₂ to Dimethyl Ether over Brønsted Acidic PdZn Catalysts

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Effect of the Si/Al ratio on the performance of hierarchical ZSM-5 zeolites for methanol aromatization

Abstract: A series of hierarchical ZSM-5 zeolites with different Si/Al ratios were successfully prepared using a seed-deduced method and the addition of organosilicone reagents into the medial synthesis system.

Cited by 137 publications

References 38 publications

Catalytic conversion of 5-hydroxymethylfurfural (5-HMF) over Pd-Ru/FAU zeolite catalysts

Catalytic conversion of 5-hydroxymethylfurfural (5-HMF) over Pd-Ru/FAU zeolite catalysts

Highly Efficient Production of Benzene-Free Aromatics from Methanol over Low-Si/Al-Ratio Alkali-Modified Fe/Zn/HZSM-5

Hydrogenation of CO2 to Dimethyl Ether over Brønsted Acidic PdZn Catalysts

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Hydrogenation of CO₂ to Dimethyl Ether over Brønsted Acidic PdZn Catalysts