Catalytic dehydration of methanol to dimethyl ether (DME) over solid-acid catalysts

Yaripour, Fereydoon; Baghaei, Fatemeh; Schmidt, Iver; Perregaard, Jens

doi:10.1016/j.catcom.2004.11.012

Cited by 260 publications

(130 citation statements)

References 10 publications

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“…The steam-to-carbon ratio was 3.0 in this study, so high concentrations of water were present in the gas phase; so may have re hydrated the acid sites, resulting in decreased acidity 28) . Increased CH4 formation rate with reaction time was also apparent above 623 K. Nearly the same amount of CH4 was observed for CH3OH reforming compared with DME reforming over a Cu/Al2O3 catalyst 4) . Therefore, CH4 formation occurs at similar rates as temperature rises for both DME and CH3OH steam reforming reac tions.…”

Section: Change In the Nature Of The Active Sitesmentioning

confidence: 63%

“…has been considered as a promising hydrogen source for Currently proposed catalysts for DME steam reform low-temperature fuel cells 1), 2) . DME can be produced ing show catalytic functions for both DME hydration from either methanol using solid acids 3), 4) or syngas using and CH3OH steam reforming. A physical mixture of a mixture of Cu-based catalysts and solid acids 5)～7) .…”

Section: Introduction So4mentioning

confidence: 99%

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Steam Reforming of Dimethyl Ether over Cu/ZnO/ZrO2 and γ-Al2O3 Mixed Catalyst Prepared by Extrusion

博之¹,

渉²,

知哉³

et al. 2008

J. Jpn. Petrol. Inst.

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Steam reforming of dimethyl ether, DME, over Cu/ZnO/ZrO2 and γ-Al2O3 mixed catalysts prepared by the extrusion technique was investigated. The catalysts were characterized by BET, pore-size distribution measure ments, N2O chemisorption, powder X-ray diffraction, and SEM-EDX analysis. The effect of reaction tempera ture on catalyst life time was investigated. Steam reforming of DME over the extruded catalyst proceeded above 623 K. The major reaction products were H2 and CO2 with relatively small amounts of CO and CH4. DME steam reforming was not restricted by the equilibrium limitation of DME hydration to CH3OH, suggesting that CH3OH produced was subsequently reformed into H2 and CO2 over the catalyst. The catalyst suffered from thermal deactivation at higher temperatures; mainly caused by a reduction in Cu dispersion in the Cu/ZnO/ZrO2 catalyst. Incorporation of ZrO2 into Cu/ZnO may stabilize Cu dispersion and increase the stability of the extruded catalyst for long-term operation.

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Section: Change In the Nature Of The Active Sitesmentioning

confidence: 63%

Section: Introduction So4mentioning

confidence: 99%

Steam Reforming of Dimethyl Ether over Cu/ZnO/ZrO2 and γ-Al2O3 Mixed Catalyst Prepared by Extrusion

博之¹,

渉²,

知哉³

et al. 2008

J. Jpn. Petrol. Inst.

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“…In general, DME can be produced by methanol dehydration over solid porous acid catalysts, such as most typical catalysts H-ZSM-5 zeolite and γ-Al 2 O 3 . Although the DME selectivity is high for methanol dehydration on γ-Al 2 O 3 [20,21], the γ-Al 2 O 3 exhibits much lower activity due to its weak Lewis acidity [21]. On the contrary, H-ZSM-5 has high activity, but it also has some disadvantages, such as low selectivity and short catalytic lifetime.…”

Section: Introductionmentioning

confidence: 99%

A Hierarchically Micro-Meso-Macroporous Zeolite CaA for Methanol Conversion to Dimethyl Ether

et al. 2016

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Abstract:A hierarchical zeolite CaA with microporous, mesoporous and macroporous structure was hydrothermally synthesized by a "Bond-Blocking" method using organo-functionalized mesoporous silica (MS) as a silica source. The characterization by XRD, SEM/TEM and N 2 adsorption/desorption techniques showed that the prepared material had well-crystalline zeolite Linde Type A (LTA) topological structure, microspherical particle morphologies, and hierarchically intracrystalline micro-meso-macropores structure. With the Bond-Blocking principle, the external surface area and macro-mesoporosity of the hierarchical zeolite CaA can be adjusted by varying the organo-functionalized degree of the mesoporous silica surface. Similarly, the distribution of the micro-meso-macroporous structure in the zeolite CaA can be controlled purposely. Compared with the conventional microporous zeolite CaA, the hierarchical zeolite CaA as a catalyst in the conversion of methanol to dimethyl ether (DME), exhibited complete DME selectivity and stable catalytic activity with high methanol conversion. The catalytic performances of the hierarchical zeolite CaA results clearly from the micro-meso-macroporous structure, improving diffusion properties, favoring the access to the active surface and avoiding secondary reactions (no hydrocarbon products were detected after 3 h of reaction).

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“…Although the functions of calumina in methanol reaction have been reported in several previous studies, their emphasis was simply focused on the crucial role of c-alumina in the dehydration reaction of methanol into dimethyl ether (DME) [25][26][27][28][29][30][31][32]. According to above studies, the reaction of methanol could be promoted by c-alumina, it was an intuitive guess that c-alumina could facilitate the formation of aromatics from methanol.…”

Section: Introductionmentioning

confidence: 99%

Effect of γ-alumina as active matrix added to HZSM-5 catalyst on the aromatization of methanol

Chen

Zhang

et al. 2015

Appl Petrochem Res

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HZSM-5-based catalyst is a recognized catalyst which is particularly selective towards the formations of aromatics in the methanol reaction. However, studies on HZSM-5-based catalyst were mainly focused on the addition of metallic or/and nonmetallic element. Quite few studies have reported the effect of active matrix such as calumina on the aromatization of methanol. In this study, calumina was introduced into HZSM-5-based catalyst for the purpose of investigating the effect of c-alumina in methanol to aromatics reaction. The catalysts were characterized by X-ray diffraction, Temperature-programmed Desorption of NH 3 (NH 3 -TPD), Pyridine adsorption FT-IR diffuse reflection spectroscopy and adsorption-desorption measurements of nitrogen, respectively. Characterizations showed that the introduction of c-alumina increased the amount of mesopores and acid sites in the catalyst. The experimental mainly includes two parts. Firstly, separate reaction performances over the catalyst with/without calumina and c-alumina showed that c-alumina could significantly promote the formations of aromatics. However, c-alumina alone could merely convert methanol to dimethyl ether with a minor quantity of gaseous hydrocarbons. Acid properties showed that the introduction of c-alumina increased the percentage of Lewis acid on catalyst surface and enhanced acid strength, as a result, promoted the production of active intermediates which was essential for aromatic formation. The rise of aromatics selectivity might be caused by the combined effect of acid site density and acid strength. Follow-up work was mainly focused on the effect of the loading amount and loading order of the catalyst with c-alumina. Results indicated that the total aromatic yield increased gradually with the increasing amount of catalyst with c-alumina regardless of the loading order of the catalyst with c-alumina. Gasoline compositions showed that the increased aromatics were at the expense of paraffins, olefins, and naphthenes. Besides, all single aromatic hydrocarbons increased gradually with the increasing amount of catalyst with c-alumina. And the aromatics had a larger variation change when methanol first passed through the catalyst with c-alumina.

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Catalytic dehydration of methanol to dimethyl ether (DME) over solid-acid catalysts

Cited by 260 publications

References 10 publications

Steam Reforming of Dimethyl Ether over Cu/ZnO/ZrO<sub>2</sub> and γ-Al<sub>2</sub>O<sub>3</sub> Mixed Catalyst Prepared by Extrusion

Steam Reforming of Dimethyl Ether over Cu/ZnO/ZrO<sub>2</sub> and γ-Al<sub>2</sub>O<sub>3</sub> Mixed Catalyst Prepared by Extrusion

A Hierarchically Micro-Meso-Macroporous Zeolite CaA for Methanol Conversion to Dimethyl Ether

Effect of γ-alumina as active matrix added to HZSM-5 catalyst on the aromatization of methanol

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