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Niobium on BEA Dealuminated Zeolite for High Selectivity Dehydration Reactions of Ethanol and Xylose into Diethyl Ether and Furfural

In this work, we investigated the role of solid-state dealumination by (NH(4))(2)SiF(6) (25% Al removal and 13% Si insertion), the impregnation of niobium (10, 18, and 25 wt. %) on dealuminated *BEA (DB) zeolite and their catalytic properties in ethanol and xylose transformations. Among all the stud...

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Autores principales: Valadares, Deborah S., Clemente, Maria Clara H., de Freitas, Elon F., Martins, Gesley Alex V., Dias, José A., Dias, Sílvia C. L.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7407447/
https://www.ncbi.nlm.nih.gov/pubmed/32610528
http://dx.doi.org/10.3390/nano10071269
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author Valadares, Deborah S.
Clemente, Maria Clara H.
de Freitas, Elon F.
Martins, Gesley Alex V.
Dias, José A.
Dias, Sílvia C. L.
author_facet Valadares, Deborah S.
Clemente, Maria Clara H.
de Freitas, Elon F.
Martins, Gesley Alex V.
Dias, José A.
Dias, Sílvia C. L.
author_sort Valadares, Deborah S.
collection PubMed
description In this work, we investigated the role of solid-state dealumination by (NH(4))(2)SiF(6) (25% Al removal and 13% Si insertion), the impregnation of niobium (10, 18, and 25 wt. %) on dealuminated *BEA (DB) zeolite and their catalytic properties in ethanol and xylose transformations. Among all the studied catalysts, 18%Nb-DB showed increased mesoporosity and external areas. A leveling effect in the number and strength of the proposed two sites (Brønsted and Lewis) present in the catalyst (n(1) = 0.24 mmol g(−1), −ΔH(1) = 49 kJ mol(−1), and n(2) = 0.20 mmol g(−1), –ΔH(2) = 42 kJ mol(−1)) in the catalyst 18%Nb-DB, might be responsible for its good activity. This catalyst presented the highest selectivity for diethyl ether, DEE (97%) with 61% conversion after 50 ethanol pulses at 230 °C (turnover number, TON DEE = 1.15). These features allowed catalytically fruitful bonding of the ethanol molecules to the neighboring sites on the channels, facilitating bimolecular ether formation through a possible SN(2) mechanism. The same catalyst was active and selective for transformation of xylose at 180 °C, showing 64% conversion and 51% selectivity for furfural (TON Furfural = 24.7) using water as a green solvent.
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spelling pubmed-74074472020-08-25 Niobium on BEA Dealuminated Zeolite for High Selectivity Dehydration Reactions of Ethanol and Xylose into Diethyl Ether and Furfural Valadares, Deborah S. Clemente, Maria Clara H. de Freitas, Elon F. Martins, Gesley Alex V. Dias, José A. Dias, Sílvia C. L. Nanomaterials (Basel) Article In this work, we investigated the role of solid-state dealumination by (NH(4))(2)SiF(6) (25% Al removal and 13% Si insertion), the impregnation of niobium (10, 18, and 25 wt. %) on dealuminated *BEA (DB) zeolite and their catalytic properties in ethanol and xylose transformations. Among all the studied catalysts, 18%Nb-DB showed increased mesoporosity and external areas. A leveling effect in the number and strength of the proposed two sites (Brønsted and Lewis) present in the catalyst (n(1) = 0.24 mmol g(−1), −ΔH(1) = 49 kJ mol(−1), and n(2) = 0.20 mmol g(−1), –ΔH(2) = 42 kJ mol(−1)) in the catalyst 18%Nb-DB, might be responsible for its good activity. This catalyst presented the highest selectivity for diethyl ether, DEE (97%) with 61% conversion after 50 ethanol pulses at 230 °C (turnover number, TON DEE = 1.15). These features allowed catalytically fruitful bonding of the ethanol molecules to the neighboring sites on the channels, facilitating bimolecular ether formation through a possible SN(2) mechanism. The same catalyst was active and selective for transformation of xylose at 180 °C, showing 64% conversion and 51% selectivity for furfural (TON Furfural = 24.7) using water as a green solvent. MDPI 2020-06-29 /pmc/articles/PMC7407447/ /pubmed/32610528 http://dx.doi.org/10.3390/nano10071269 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Valadares, Deborah S.
Clemente, Maria Clara H.
de Freitas, Elon F.
Martins, Gesley Alex V.
Dias, José A.
Dias, Sílvia C. L.
Niobium on BEA Dealuminated Zeolite for High Selectivity Dehydration Reactions of Ethanol and Xylose into Diethyl Ether and Furfural
title Niobium on BEA Dealuminated Zeolite for High Selectivity Dehydration Reactions of Ethanol and Xylose into Diethyl Ether and Furfural
title_full Niobium on BEA Dealuminated Zeolite for High Selectivity Dehydration Reactions of Ethanol and Xylose into Diethyl Ether and Furfural
title_fullStr Niobium on BEA Dealuminated Zeolite for High Selectivity Dehydration Reactions of Ethanol and Xylose into Diethyl Ether and Furfural
title_full_unstemmed Niobium on BEA Dealuminated Zeolite for High Selectivity Dehydration Reactions of Ethanol and Xylose into Diethyl Ether and Furfural
title_short Niobium on BEA Dealuminated Zeolite for High Selectivity Dehydration Reactions of Ethanol and Xylose into Diethyl Ether and Furfural
title_sort niobium on bea dealuminated zeolite for high selectivity dehydration reactions of ethanol and xylose into diethyl ether and furfural
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7407447/
https://www.ncbi.nlm.nih.gov/pubmed/32610528
http://dx.doi.org/10.3390/nano10071269
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