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Mechanisms for Conversion of Oxygenates to Light Olefins over Nanozeolite Catalysts
https://orcid.org/https://orcid.org/0000-0002-6155-5507
https://orcid.org/https://orcid.org/0000-0002-9253-8523
https://orcid.org/https://orcid.org/0000-0001-8762-8025
https://orcid.org/https://orcid.org/0000-0002-9748-3445
https://orcid.org/https://orcid.org/0000-0002-3397-5539
https://orcid.org/https://orcid.org/0000-0001-7183-7324
https://orcid.org/https://orcid.org/0000-0003-2534-2624
In the production of light olefins from dimethyl ether, a nanozeolite catalyst modified with lanthanum and zirconium exhibited lower activity and selectivity than a magnesium-loaded zeolite catalyst. This is due to a higher percentage of strong acid sites in La–Zr/HZSM-5, which promoted secondary reactions and decreased the selectivity towards light olefins. Furthermore, the difference in the catalytic properties of the samples modified with Mg and La–Zr can be explained by the different concentrations of the methanol product: the methanol content was markedly higher in the presence of La–Zr/HZSM-5 than with Mg/HZSM-5. To gain better insight into the role of methanol in the synthesis of light olefins from dimethyl ether, the relative activity of Brønsted acid sites on the catalyst surface in the conversion of methanol and dimethyl ether was comparatively assessed using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). It was demonstrated that at high temperatures (above 260°C) the conversion of both DME and methanol occurs by the oxonium–ylide mechanism. However, there are differences in the formation routes of primary intermediates: formaldehyde from methanol, and ketene from dimethyl ether.
Mechanisms for Conversion of Oxygenates to Light Olefins over Nanozeolite Catalysts
https://orcid.org/https://orcid.org/0000-0002-6155-5507
https://orcid.org/https://orcid.org/0000-0002-9253-8523
https://orcid.org/https://orcid.org/0000-0001-8762-8025
https://orcid.org/https://orcid.org/0000-0002-9748-3445
https://orcid.org/https://orcid.org/0000-0002-3397-5539
https://orcid.org/https://orcid.org/0000-0001-7183-7324
https://orcid.org/https://orcid.org/0000-0003-2534-2624
In the production of light olefins from dimethyl ether, a nanozeolite catalyst modified with lanthanum and zirconium exhibited lower activity and selectivity than a magnesium-loaded zeolite catalyst. This is due to a higher percentage of strong acid sites in La–Zr/HZSM-5, which promoted secondary reactions and decreased the selectivity towards light olefins. Furthermore, the difference in the catalytic properties of the samples modified with Mg and La–Zr can be explained by the different concentrations of the methanol product: the methanol content was markedly higher in the presence of La–Zr/HZSM-5 than with Mg/HZSM-5. To gain better insight into the role of methanol in the synthesis of light olefins from dimethyl ether, the relative activity of Brønsted acid sites on the catalyst surface in the conversion of methanol and dimethyl ether was comparatively assessed using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). It was demonstrated that at high temperatures (above 260°C) the conversion of both DME and methanol occurs by the oxonium–ylide mechanism. However, there are differences in the formation routes of primary intermediates: formaldehyde from methanol, and ketene from dimethyl ether.
Mechanisms for Conversion of Oxygenates to Light Olefins over Nanozeolite Catalysts
https://orcid.org/https://orcid.org/0000-0002-6155-5507
https://orcid.org/https://orcid.org/0000-0002-9253-8523
https://orcid.org/https://orcid.org/0000-0001-8762-8025
https://orcid.org/https://orcid.org/0000-0002-9748-3445
https://orcid.org/https://orcid.org/0000-0002-3397-5539
https://orcid.org/https://orcid.org/0000-0001-7183-7324
https://orcid.org/https://orcid.org/0000-0003-2534-2624
In the production of light olefins from dimethyl ether, a nanozeolite catalyst modified with lanthanum and zirconium exhibited lower activity and selectivity than a magnesium-loaded zeolite catalyst. This is due to a higher percentage of strong acid sites in La–Zr/HZSM-5, which promoted secondary reactions and decreased the selectivity towards light olefins. Furthermore, the difference in the catalytic properties of the samples modified with Mg and La–Zr can be explained by the different concentrations of the methanol product: the methanol content was markedly higher in the presence of La–Zr/HZSM-5 than with Mg/HZSM-5. To gain better insight into the role of methanol in the synthesis of light olefins from dimethyl ether, the relative activity of Brønsted acid sites on the catalyst surface in the conversion of methanol and dimethyl ether was comparatively assessed using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). It was demonstrated that at high temperatures (above 260°C) the conversion of both DME and methanol occurs by the oxonium–ylide mechanism. However, there are differences in the formation routes of primary intermediates: formaldehyde from methanol, and ketene from dimethyl ether.
Mechanisms for Conversion of Oxygenates to Light Olefins over Nanozeolite Catalysts
Pet. Chem.
Obukhova, T. K. (author) / Batova, T. I. (author) / Kolesnikova, E. E. (author) / Panin, A. A. (author) / Arapova, O. V. (author) / Golubev, K. B. (author) / Kolesnichenko, N. V. (author)
Petroleum Chemistry ; 62 ; 1242-1248
2022-10-01
7 pages
Article (Journal)
Electronic Resource
English
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