Gas phase dehydration of glycerol to acrolein over WO3-based catalysts prepared by non-hydrolytic sol–gel synthesis

[EN] Solid acid catalysts based on WO3¿SiO2 and WO3¿ZrO2¿SiO2 were prepared by one-pot non-hydrolytic sol¿gel method and tested in the gas phase glycerol dehydration to acrolein. Their structural and textural characteristics were determined by X-ray diffraction (XRD), N2 adsorption, X-ray energy dispersive spectroscopy (XEDS), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Their acid characteristics were studied by both temperature programmed desorption of ammonia (NH3-TPD) and FTIR of adsorbed pyridine. Under our operating conditions, all the catalysts were active and selective in the transformation of glycerol to acrolein, which was always the main reaction product. The high selectivity to acrolein is achieved on catalysts presenting a higher proportion of Brønsted acid sites. In addition, the role of oxygen in the feed on catalytic performance of these catalysts is also discussed.
The authors would like to acknowledge the DGICYT (CTQ2015-68951-C3-1-R, CTQ2015-68951-C3-3-R and SEV-2016-0683) and Secretary of State for International Cooperation in Spain (Project AP/040992/11) and Ministry of Higher Education and Scientific Research of Algeria for the National Exceptional Program for the fellowships. D. D. thanks MINECO and Severo Ochoa Excellence Program for his fellowship (SVP-2014-068669). Authors also would like to thank the Electron Microscopy Service of Universitat Politecnica de Valencia for their support.