Gas-phase dehydration of glycerol to acrolein over Al2O3-, SiO2- and TiO2-supported Nb- and W-oxide catalysts

TY - JOUR

T1 - Gas-phase dehydration of glycerol to acrolein over Al2O3-, SiO2- and TiO2-supported Nb- and W-oxide catalysts

AU - Massa, Mariano

AU - Andersson, Arne

AU - Finocchio, Elisabetta

AU - Busca, Guido

PY - 2013

Y1 - 2013

N2 - Hypothetical monolayers loadings of niobium and tungsten oxide supported on alumina, silica and titania were investigated as catalysts for the dehydration of glycerol to produce acrolein. Besides activity measurements, to have information about the supported structures the catalysts were characterized by XRD, Raman spectroscopy, XPS, XANES and FTIR combined with adsorption of pyridine and CO2. Compared with silica showing the presence of crystalline Nb2O5 and WO3, alumina and titania gave better dispersion and formation of hydrated niobate and tungstate species. Deactivation of the catalysts occurred with time on stream. However, the stability was improved considerably by adding oxygen to the feed. A dependence of the selectivity to acrolein on the Brønsted acidity of the catalyst was observed. Under anaerobic conditions an alumina-supported mixed Nb-W-oxide catalyst gave a selectivity of more than 70% for glycerol conversions above 40%. Even better selectivity was obtained using a catalyst with tungsten oxide supported on titania, which gave 80% selectivity under aerobic conditions at high conversion.

AB - Hypothetical monolayers loadings of niobium and tungsten oxide supported on alumina, silica and titania were investigated as catalysts for the dehydration of glycerol to produce acrolein. Besides activity measurements, to have information about the supported structures the catalysts were characterized by XRD, Raman spectroscopy, XPS, XANES and FTIR combined with adsorption of pyridine and CO2. Compared with silica showing the presence of crystalline Nb2O5 and WO3, alumina and titania gave better dispersion and formation of hydrated niobate and tungstate species. Deactivation of the catalysts occurred with time on stream. However, the stability was improved considerably by adding oxygen to the feed. A dependence of the selectivity to acrolein on the Brønsted acidity of the catalyst was observed. Under anaerobic conditions an alumina-supported mixed Nb-W-oxide catalyst gave a selectivity of more than 70% for glycerol conversions above 40%. Even better selectivity was obtained using a catalyst with tungsten oxide supported on titania, which gave 80% selectivity under aerobic conditions at high conversion.

KW - Glycerol

KW - Dehydration

KW - Acrolein

KW - Supported niobia

KW - Supported tungsten oxide

KW - Supported Nb-W-oxide

KW - Al2O3

KW - TiO2

KW - SiO2

KW - acidity

U2 - 10.1016/j.jcat.2013.07.022

DO - 10.1016/j.jcat.2013.07.022

M3 - Article

VL - 307

SP - 170

EP - 184

JO - Journal of Catalysis

JF - Journal of Catalysis

SN - 1090-2694

ER -