Oxidative desulfurization (ODS) of model fuel containing benzothiophene (BT) or thiophene (Th) has been carried out with WO(x)/ZrO2 catalyst, which was calcined at various temperatures. Based on the conversion of BT in the model fuel, it can be shown that the optimum calcination temperature of WOx/ZrO2 catalyst is around 700 °C. The most active catalyst is composed of tetragonal zirconia (ZrO2) with well dispersed polyoxotungstate species and it is necessary to minimize the contents of the crystalline WO3 and monoclinic ZrO2 for a high BT conversion. The oxidation rate was interpreted with the first-order kinetics, and it demonstrated the importance of electron density since the kinetic constant for BT was higher than that for Th even though the BT is larger than Th in size. A WOx/ZrO2 catalyst, treated suitably, can be used as a reusable active catalyst in the ODS.
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http://dx.doi.org/10.1016/j.jhazmat.2011.12.059 | DOI Listing |
J Nanosci Nanotechnol
February 2018
Department of Chemical and Biological Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea.
p-Xylene (PX) is an important large-volume commodity chemical in the petrochemical industry. Therefore, research on producing PX from bio-mass-derived resources is a considerable interest in relation to future alternative technologies. Recently, a new potential route for the direct and selective production of bio-based PX was reported, referred to as the Diels-Alder cycloaddition of biomassderived 2,5-dimethylfuran (DMF) and ethylene followed by the dehydration of an intermediate.
View Article and Find Full Text PDFJ Hazard Mater
February 2012
Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, Daegu 702-701, Republic of Korea.
Oxidative desulfurization (ODS) of model fuel containing benzothiophene (BT) or thiophene (Th) has been carried out with WO(x)/ZrO2 catalyst, which was calcined at various temperatures. Based on the conversion of BT in the model fuel, it can be shown that the optimum calcination temperature of WOx/ZrO2 catalyst is around 700 °C. The most active catalyst is composed of tetragonal zirconia (ZrO2) with well dispersed polyoxotungstate species and it is necessary to minimize the contents of the crystalline WO3 and monoclinic ZrO2 for a high BT conversion.
View Article and Find Full Text PDFPhys Chem Chem Phys
September 2009
UPMC-Université Pierre et Marie Curie (Paris 06), Laboratoire de Réactivite de Surface, UMR 7197, Paris, France.
EXAFS spectroscopy is shown as a tool of prime importance to probe the formation of metal-oxygen-support bonds and unravel the surface molecular structure in oxide-supported systems through two examples: (i) a molecular metal complex (Ni(II) bisglycinate) characterized after impregnation and drying on Al2O3, and (ii) a tungsten oxide nanophase characterized after deposition on zirconia and high temperature thermal treatment (tungstated zirconia catalysts, i.e. WOx/ZrO2).
View Article and Find Full Text PDFJ Phys Chem B
March 2005
Institut de Recherches sur la Catalyse/CNRS, UPR 5401, 2 avenue A. Einstein, 69626 Villeurbanne, France.
W/ZrO(2) catalysts were prepared using anionic exchange of peroxotungstate species with hydroxyl groups of zirconium hydroxide at low pH. The solids were dried and calcined under air at 700 degrees C. Each step of this novel method of preparation was investigated by Raman spectroscopy.
View Article and Find Full Text PDFInorg Chem
March 2006
Centro de Engenharia Biológica e Química, Instituto Superior Técnico, Universidade Técnica de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal.
The synthesis and characterization of a series of mixed W-Zr polynuclear Lindqvist-type complexes, deriving from hexatungstate [W6O19]2-, are described in this work. This family of compounds is built from {W5O18Zr}2- moieties as shown by the X-ray structures of the monomeric [W5O18Zr(H2O)(3-n)(DMSO)n]2- (n = 1 and 2) and dimeric [{W5O18Zr(mu-OH)}2]6- anions. A comprehensive spectroscopic study (183W NMR, FTIR, Raman, EXAFS, and EPR) of these compounds is presented.
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