Methanol conversion to olefins over ZSM-5 I. Effect of temperature and zeolite SiO2/Al2O3

Chang, Clarence D.; Chu, Cynthia T-W.; Socha, Richard F.

doi:10.1016/0021-9517(84)90374-9

Cited by 252 publications

(67 citation statements)

References 9 publications

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“…The ratio of propylene to ethylene was 6.3 and the selectivity to propylene 53 %, whichi sa mong the highest selectivities reported in the literature. [10][11][12][13][14][15][16][17] The most important characteristics of this catalysta re very small nanosized particles built of intergrown crystallined omains responsible for largee xternals urfacea rea and their lower acid sites strength and density.…”

Section: Discussionmentioning

confidence: 99%

“…[7][8][9] In the early study of Chang et al the ratio of propylene/ethylene (P/E) of 4.9 has been reached for the sample with aS iO 2 /Al 2 O 3 ratio of 1670. [10] In general, propylene selectivity rises with decreasing zeolite acidity.T he same effect of an increase of the propylene to ethylene ratio and selectivity to light olefinsh as been observedb yP rinz and Riekert over ZSM-5 catalysts with ah igh Si/Al ratio. [11] At low conversion (< 70 %) the selectivity for light olefins wasf ound to be higherf or smaller crystals.…”

Section: Introductionmentioning

confidence: 99%

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Tuning Zeolite Properties for a Highly Efficient Synthesis of Propylene from Methanol

Palčić

Ordomsky

Qin

et al. 2018

Chemistry A European J

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A series of nanosized ZSM-5 samples was synthesized at 170, 150, 120, and 100 °C. Experimental data show that the decrease of crystallization temperature leads to significant changes in zeolite properties. Crystals synthesized at 100 °C exhibit many framework defects with lower acid-site density, strength, and a larger external surface area. The selectivity to light olefins and the propylene-to-ethylene ratio increases as the crystallization temperature decreases. A propylene-to-ethylene ratio of above 6 with the highest selectivity to propylene of 53 % was obtained over ZSM-5 catalyst prepared at 100 °C. The stability of the nanosized zeolite in methanol to olefins (MTO) was also improved compared to the industrial sample with a similar Si/Al ratio. This catalytic performance is a result of the decrease in the acid-site density, strength, and the crystals' size, providing a shorter diffusion path and larger external surface area. The presence of structural defects and a different external surface in the crystals has been shown to play an important role in the MTO catalyst performance.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Tuning Zeolite Properties for a Highly Efficient Synthesis of Propylene from Methanol

Palčić

Ordomsky

Qin

et al. 2018

Chemistry A European J

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“…Although the current production of light olefins is based on naphtha steam cracking, the high energy requirement of this process (with high CO 2 emissions) and its reduced selectivity of propylene explain the interest of other processes [3]. In this way, the increasing industrial implantation of the MTO (methanol to olefins) process [4] offers the possibility of obtaining methanol from different fossil sources alternative to petroleum (carbon, natural gas) and also from biomass (via gasification). Alternatively, the DTO (dimethyl ether to olefins) process has some important advantages.…”

Section: Introductionmentioning

confidence: 99%

Nature and Location of Carbonaceous Species in a Composite HZSM-5 Zeolite Catalyst during the Conversion of Dimethyl Ether into Light Olefins

et al. 2017

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Abstract:The deactivation of a composite catalyst based on HZSM-5 zeolite (agglomerated in a matrix using boehmite as a binder) has been studied during the transformation of dimethyl ether into light olefins. The location of the trapped/retained species (on the zeolite or on the matrix) has been analyzed by comparing the properties of the fresh and deactivated catalyst after runs at different temperatures, while the nature of those species has been studied using different spectroscopic and thermogravimetric techniques. The reaction occurs on the strongest acid sites of the zeolite micropores through olefins and alkyl-benzenes as intermediates. These species also condensate into bulkier structures (polyaromatics named as coke), particularly at higher temperatures and within the mesoand macropores of the matrix. The critical roles of the matrix and water in the reaction medium have been proved: both attenuating the effect of coke deposition.

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“…A decrease in Brǿnsted acidity of the catalysts with the improvement of SiO 2 /Al 2 O 3 ratio favors the formation of propylene in the reaction and brings about an increase in propylene to ethylene (P/E) ratio. Chang et al [20] also reported that decreasing Brǿnsted acidity of HZSM-5 zeolite could improve its selectivity to propylene in MTO reaction. The MTO reaction over SAPO-34 catalysts with different SiO 2 /Al 2 O 3 ratio is given in Fig.…”

Section: Catalyst Characterizationmentioning

confidence: 95%

Effect of SiO2/Al2O3 ratio on the conversion of methanol to olefins over molecular sieve catalysts

Wang

et al. 2010

Front. Chem. Sci. Eng.

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A series of SAPO-34 molecular sieves with different SiO 2 /Al 2 O 3 ratios have been synthesized for the methanol-to-olefin (MTO) reaction. Their physico-chemical properties are characterized by various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR) and N 2 adsorption-desorption. The results are compared with those of the commercial HZSM-5, which show that the crystallinity and particle diameter of SAPO-34 as well as HZSM-5 increase with SiO 2 /Al 2 O 3 ratio. The variation of BET surface area of SAPO-34 is different from that of HZSM-5 and the sample with SiO 2 /Al 2 O 3 ratio of 0.4 exhibits the highest BET surface area. FT-IR spectra indicate that HZSM-5 has both Brǿnsted and Lewis acid sites and Brǿnsted acid sites are stronger, whereas SAPO-34 samples are dominated only by Lewis acid sites. When the SiO 2 /Al 2 O 3 ratio increases, propylene and butylenes become the predominant product of the MTO reaction over HZSM-5. In contrast, the main products of this reaction catalyzed by SAPO-34 are ethylene and propylene. According to the product distribution, the reaction mechanism over HZSM-5 catalysts is proposed.

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Methanol conversion to olefins over ZSM-5 I. Effect of temperature and zeolite SiO2/Al2O3

Cited by 252 publications

References 9 publications

Tuning Zeolite Properties for a Highly Efficient Synthesis of Propylene from Methanol

Tuning Zeolite Properties for a Highly Efficient Synthesis of Propylene from Methanol

Nature and Location of Carbonaceous Species in a Composite HZSM-5 Zeolite Catalyst during the Conversion of Dimethyl Ether into Light Olefins

Effect of SiO2/Al2O3 ratio on the conversion of methanol to olefins over molecular sieve catalysts

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