Selective transformation of methanol into light olefins over a mordenite catalyst: reaction scheme and mechanism

Fougerit, J.M.; Gnep, N.S.; Guisnet, M.

doi:10.1016/s1387-1811(98)00322-9

Cited by 28 publications

(11 citation statements)

References 21 publications

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“…A fair amount of methane is detected in the effluent, again indicative of rapid deactivation. Methane is thought to be formed directly from the dehydrogenation and disproportionation of dimethyl ether or methanol during the initial stages of reaction [69,70], but also from the dealkylation of polymethylbenzenes or coke molecules as suggested by Guisnet and co-workers [71]. immediately before the methanol breakthrough, the total coke amount corresponds to 85% of the maximum coke amount detected.…”

Section: Mordenitementioning

confidence: 96%

A Straightforward Descriptor for the Deactivation of Zeolite Catalyst H-ZSM-5

et al. 2017

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Catalyst deactivation during the methanol-to-hydrocarbons (MTH) reaction was investigated using five different commercially prepared microporous catalysts, including Mordenite, ZSM-22, ZSM-5, zeolite Beta and SAPO-34. The reaction was carried out in a fixed bed reactor at a constant feed rate per gram of catalyst. Deactivated and partially deactivated catalysts were obtained at increasing reaction times. The whole of the catalyst beds were characterized using nitrogen adsorption, thermogravimetric analysis, a dissolution-extraction protocol, and UV-Raman spectroscopy, focusing primarily on methods suitable for the quantification of the coke. The results illustrate that topology is the dominant parameter that influences not only catalyst lifetime and product distribution, but also the nature of the species causing the deactivation. For all catalyst topologies, when the entire catalyst bed is examined together, the micropore volume and BET surface area decrease more rapidly than total coke from TGA increases at short reaction times. In the materials with the more restricted access to the internal voids, such as ZSM-22 and SAPO-34, the loss of activity is to a large extent due to species which are soluble in dichloromethane and give rise to distinct features in the Raman spectra. For the Mordenite and Beta catalysts, which have larger pores comprising three dimensional networks, and to some extent for the ZSM-5 catalyst employed, the accumulation of more coke species which are insoluble in dichloromethane, presumably on the external surface of the zeolite crystals, is observed. This is linked to the appearance of more pronounced D and G bands in the Raman spectra, indicative of extended carbon species.

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Section: Mordenitementioning

confidence: 96%

A Straightforward Descriptor for the Deactivation of Zeolite Catalyst H-ZSM-5

et al. 2017

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“…It is well known that there are primary and secondary reactions in conversion of methanol to hydrocarbon over H-ZSM-5 [18][19][20], and Furthermore, over the large pore dealuminated mordenite, a high selectivity to light alkenes can also be obtained, and C 3 -C 7 alkenes were considered as primary products from the direct transformation of DME, but ethylene mainly results from secondary cracking of C 5 -C 7 alkenes [21]. The product distribution in DME conversion over Pd-beat zeolite may also be controlled by primary or secondary reactions or both of them.…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, it is well known that zeolite beta, which possesses 3-dimensional 12-membered-ring pore openings, is an intergrowth hybrid of two distinct but closely related structures with diameters of 5.5 · 5.5 Å channels along [001] and 6.4 · 7.6 Å channels perpendicular to [001] [22,23], which, to some extent, is similar to the pore structure of mordenite, where two kinds of (2) DME converts completely and around 0.1-0.5% CO X is produced channels are found and considered favorable for the formation of light hydrocarbons [21,24]. Hence, the structure of zeolite beta may produce some impacts on the catalytic performance of zeolite beta.…”

Section: Resultsmentioning

confidence: 99%

Selective Transformation of Dimethyl Ether into Small Molecular Hydrocarbons Over Large-pore Beta Zeolite

Zhu

Kaneko

et al. 2007

Catal Lett

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“…selectivity begin to reduce sharply at initial times of reaction while the light olefin selectivity is still high. Also methane content that results from both primary transformation dimethylether and from secondary reactions of protolytic cracking of alkanes and demethylation of cokes [32] increases continuously in the gas product with TOS (Fig. 12).…”

Section: The Effect Of Order Of Reagents Additionmentioning

confidence: 99%

Preparation and Evaluation of the Modified Nanoparticle SAPO-18 for Catalytic Conversion of Methanol to Light Olefins

et al. 2015

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Silicoaluminophosphate-18 can be considered as an effective catalyst for methanol conversion to olefins (MTO). A series of SAPO-18 were prepared to investigate the effects of aging pretreatment on crystallization time. The results exhibit that stirring aging, in addition to reducing the overall particle size of SAPO-18, decreases the crystallization time from 168 to 65 h. Also, the effects of addition order of the reagents and crystallization time on physiochemical properties of the SAPO-18 nanoparticles were studied. Finally detailed investigations were carried out on the catalytic performance of the samples in MTO process and the best catalyst was determined. Graphical AbstractKeywords SAPO-18 Á Methanol to olefin process (MTO) Á Aging Á Crystallinity Á Preparation method

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Selective transformation of methanol into light olefins over a mordenite catalyst: reaction scheme and mechanism

Cited by 28 publications

References 21 publications

A Straightforward Descriptor for the Deactivation of Zeolite Catalyst H-ZSM-5

A Straightforward Descriptor for the Deactivation of Zeolite Catalyst H-ZSM-5

Selective Transformation of Dimethyl Ether into Small Molecular Hydrocarbons Over Large-pore Beta Zeolite

Preparation and Evaluation of the Modified Nanoparticle SAPO-18 for Catalytic Conversion of Methanol to Light Olefins

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