Browsing by Author "Bassi, R."

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    Conversion of levulinic acid over rhenium oxide catalysts: Effect of metal content
    (2021) Bassi, R.; Baeza, P.; Sepulveda, C.; Ghampson, I. T.; Camu, E.; Bruckner, A.; Bentrup, U.; Fierro, J. L. G.; Escalona, N.
    The conversion of levulinic acid over rhenium oxide catalysts supported on ZrO2 and SiO2 in a batch reactor at 200 degrees C and 5 MPa of H-2 pressure was studied. The catalysts were prepared by incipient wetness impregnation with nominal loadings of 5-18 wt.%. The catalysts were characterized by N-2 physisorption, field emission scanning electron microscopy, X-ray diffraction, H-2-temperature programmed reduction, Fourier transform infrared spectroscopy of adsorbed pyridine, and X-ray photoelectron spectroscopy. The catalysts were highly active and selective to gamma-valerolactone. Catalytic activity, expressed as initial reaction rate and based on catalyst weight, was correlated with dispersion. The difference in the activity trend was attributed to ReOx-support interaction: ZrO2 interacted more strongly with ReOx and modified the electronic character of the sites, whereas SiO2 interacted weakly with ReOx, leading to unmodified Re active sites, irrespective of Re loading. All the catalysts exceeded 90 % selectivity to GVL.
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    SUPPORT EFFECT ON CONVERSION OF QUINOLINE OVER ReS2 CATALYST
    (2016) Bassi, R.; Villarroel, M.; Gil-Llambias, F. J.; Baeza, P.; Garcia-Fierro, J. L.; Martinez, N.; Olivera, P.; Leiva, K.; Escalona, N.
    The conversion of quinoline over ReS2 supported on gamma-Al2O3, SiO2, ZrO2 and TiO2 catalysts in a batch reactor at 300 degrees C and 5 MPa of hydrogen pressure was studied. The catalysts were prepared by wet impregnation with a loading of 1.5 atoms of Re per nm(2) of support. The catalysts were characterized by N-2 adsorption, X-ray photoelectron spectroscopy (XPS) and X-ray powder diffraction (XRD). The Re(x)/supports catalysts displayed high activities for the conversion of quinoline, although negligible formation of N-free compounds (hydrodenitrogenation) were observed. The intrinsic activities of ReS2 were modified by the support decreased in the order: Re/TiO2 > Re/ZrO2 > Re/SiO2 > Re/g-Al2O3. The highest activity displayed by the Re/TiO2 catalyst was correlated with the Re dispersion and formation of ReS2 species. Meanwhile, the lower conversion of quinoline over the Re/ZrO2, Re/SiO2 and Re/g-Al2O3 catalysts was related to the combined effect of the textural properties of catalysts and the formation of ReS(2-x) species on the supports.