abstract
Zirconium-tungsten mixed oxides (ZrW) are effective catalysts in the aqueous-phase dehydration of D-xylose to 2-furfuraldehyde (Fur), at 170 degrees C. The texture and acid properties of ZrW materials were modified to enhance Fur yields. The catalysts prepared by co-condensation without a templating agent (ZrW(X), X = NO3, Cl; X is related to the type of zirconium precursor) possess relatively low specific surface area and amounts of accessible acid sites, leading to a modest Fur yield of ca. 35% at 99% conversion. The use of a templating agent in the preparation of mesoporous ZrW (ZrW-MP) increased considerably the specific surface area and the amount of accessible acid sites, which resulted in enhanced Fur yields (42%) reached at comparable conversions. Further improvements in Fur yields at high conversions were accomplished by introducing aluminium in the catalyst preparation procedure to give ZrAlW-MP (51% yield at 98% conversion). Fairly good catalytic results were also obtained in the case of the ZrAlW-MP catalyst, using solely water as solvent (46% yield at 93% conversion). A study of the identification of the reaction by-products by two-dimensional gas chromatography (GC x GC) combined with time-of-flight mass spectrometry (ToFMS) was carried out. (C) 2012 Elsevier B. V. All rights reserved.
keywords
HIGH-TEMPERATURE; PHASE DEHYDRATION; SUSTAINABLE PRODUCTION; SUPERCRITICAL WATER; SURFACE-ACIDITY; D-FRUCTOSE; D-GLUCOSE; TUNGSTEN; ZIRCONIA; BIOMASS
subject category
Chemistry; Engineering
authors
Antunes, MM; Lima, S; Fernandes, A; Candeias, J; Pillinger, M; Rocha, SM; Ribeiro, MF; Valente, AA
our authors
Anabela Tavares Aguiar Valente
Principal Researcher
Maria Margarida Feitor Pintão Moreno Antunes
Junior Researcher
Martyn Pillinger
Principal Researcheracknowledgements
We are grateful to the Fundacao para a Ciencia e a Tecnologia (FCT), the Programa Operacional Ciencia e Inovacao (POCI) 2010, Orcamento do Estado (OE), Fundo Europeu de Desenvolvimento Regional (FEDER) for general funding (project POCTI/QUI/56112/2004), and to CICECO and QOPNA (Research Unit 62/94, project PEst-C/QUI/UI0062/2011). We acknowledge the FCT for a PhD grant to M. M. A. (SFRH/BD/61648/2009) and a post-doctoral grant to S. L. (SRFH/BPD/23765/2005). The authors thank Prof. C. P. Neto (University of Aveiro) for helpful discussions, Dr. F. Domingues (University of Aveiro) for access to HPLC equipment, and Magda Santos for the assistance in the GC x GC-ToFMS analyses.