Gas phase dehydration of glycerol catalyzed by rutile TiO2-supported heteropolyacids

Gas phase dehydration of glycerol catalyzed by the rutile TiO2-supported heteropolyacids was investigated. The TiO2-supported heteropolyacid catalysts were prepared by the incipient wetness impregnation method using silicotungstic, phosphotungstic, and phosphomolybdic acids as active compounds. The as-prepared catalysts were characterized by X-ray diffraction, infrared spectroscopy, temperature programmed desorption of ammonia, and surface area measurement. The heteropolyacids supported by rutile TiO2 were crystallites. The catalytic activity of the catalysts in the gas phase dehydration of glycerol was significantly affected by the type and loading of heteropolyacids. TiO2-supported silicotungstic acid (20 wt.%) catalyst showed the highest catalytic activity with an acrolein selectivity of 80 mol% at a conversion of glycerol of 99% and a reaction temperature of 280 °C under ambient pressure. The possible reaction route in the gas phase dehydration of glycerol catalyzed by the TiO2-supported heteropolyacid catalysts was also discussed briefly.