Título:	Niobium on BEA dealuminated zeolite for high selectivity dehydration reactions of ethanol and xylose into diethyl ether and furfural
Autor(es):	Valadares, Deborah da Silva Clemente, Maria Clara Hortêncio Freitas, Elon Ferreira de Martins, Gesley Alex Veloso Dias, José Alves Dias, Silvia Clara Loureiro
ORCID:	https://orcid.org/0000-0003-4622-2445 https://orcid.org/0000-0003-0042-0091 https://orcid.org/0000-0002-3351-9226
Assunto:	Zeólitas Nióbio Desidratação de etanol Éter Dietílico Xilose Furfural
Data de publicação:	2020
Editora:	MDPI
Referência:	VALADARES, Deborah S. et al. Niobium on BEA dealuminated zeolite for high selectivity dehydration reactions of ethanol and xylose into diethyl ether and furfural. Nanomaterials, v. 10, n. 7, 2020. DOI: https://doi.org/10.3390/nano10071269. Disponível em: https://www.mdpi.com/2079-4991/10/7/1269.
Abstract:	: In this work, we investigated the role of solid-state dealumination by (NH4)2SiF6 (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 (n1 = 0.24 mmol g−1 , −∆H1 = 49 kJ mol−1 , and n2 = 0.20 mmol g−1 , –∆H2 = 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 SN2 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.
Unidade Acadêmica:	Instituto de Química (IQ)
Licença:	© 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/).
DOI:	https://doi.org/10.3390/nano10071269
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