Niobium on BEA Dealuminated Zeolite for High Selectivity Dehydration Reactions of Ethanol and Xylose into Diethyl Ether and Furfural
| Autor: | Maria Clara Hortencio Clemente, Gesley Alex Veloso Martins, Elon F. de Freitas, José A. Dias, Deborah S. Valadares, Sílvia C.L. Dias |
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| Rok vydání: | 2020 |
| Předmět: |
General Chemical Engineering
Xylose diethyl ether Furfural Article Catalysis lcsh:Chemistry Keywords: *BEA zeolite chemistry.chemical_compound Xilose Nb impregnation ethanol dehydration General Materials Science Éter Dietílico Zeolite Ethanol Chemistry furfural Desidratação de etanol solid-state dealumination BEA zeolite Solvent Nióbio lcsh:QD1-999 Zeólitas Diethyl ether Selectivity xylose dehydration Nuclear chemistry |
| Zdroj: | Nanomaterials Nanomaterials, Vol 10, Iss 1269, p 1269 (2020) Repositório Institucional da UnB Universidade de Brasília (UnB) instacron:UNB Volume 10 Issue 7 |
| ISSN: | 2079-4991 |
| Popis: | 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 (Brø nsted and Lewis) present in the catalyst (n1 = 0.24 mmol g&minus 1, &minus &Delta H1 = 49 kJ mol&minus 1, and n2 = 0.20 mmol g&minus 1, &ndash H2 = 42 kJ mol&minus 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. |
| Databáze: | OpenAIRE |
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