Glycerol conversion to acrylonitrile by consecutive dehydration over WO3/TiO2 and ammoxidation over Sb-(Fe,V)-O

Authors: Carsten Liebig, Sébastien Paul, Benjamin Katryniok, Cyrille Guillon, Jean-Luc Couturier, Jean-Luc Dubois, Franck Dumeignil, Wolfgang F. Hoelderich

Abstract:
The indirect ammoxidation of glycerol to acrylonitrile via intermediate formation of acrolein was studied using a tandem reactor coupling a dehydration step with an ammoxidation step. For the first step of dehydration of glycerol to acrolein, we used a previously optimized WO₃/TiO₂ catalyst, while Sb-V-O or Sb-Fe-O catalysts were developed and used for the subsequent ammoxidation step. Especially, the SbFe-O catalysts were found highly selective and thus were more-deeply investigated. The corresponding catalysts were characterized by nitrogen physisorption, X-ray powder diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, and temperature-programmed reduction in the presence of H₂. We found that the presence of a FeSbO₄ mixed phase on the synthesized samples was correlated to a high selectivity to acrylonitrile. Further, we observed an increase in selectivity to acrylonitrile with the reaction time, which was explained by the progressive formation of additional amounts of FeSbO₄ on the catalysts during the reaction. Finally, the reaction parameters (temperature, catalyst amount, molar NH₃/AC ratio and molar O₂/AC ratio) for the catalyst with an Sb/Fe molar ratio of 0.6 were optimized, whereby a maximum yield in acrylonitrile of 40% (based on glycerol) could be achieved.

Keywords:
Glycerol
Indirect ammoxidation
Acrolein
Acrylonitrile
Tandem-reactor

Published in: Applied Catalysis B: Environmental (Volumes 132–133, Pages 1-552, 27 March 2013)

Publisher: Elsevier  

ISSN Information: 0926-3373

Glycerol conversion to acrylonitrile by consecutive dehydration over WO3/TiO2 and ammoxidation over Sb-(Fe,V)-O

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