Catalytic performance of vanadium pyrophosphate oxides (VPO) in the oxidative dehydration of glycerol

A series of vanadium pyrophosphate oxide catalysts were prepared by thermally treating catalyst precursor VOHPO4·0.5H2O in the temperature range of 500–900 °C in nitrogen and their catalytic activities were evaluated in glycerol dehydration with molecular oxygen. The catalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, thermogravimetric–differential thermal analysis and temperature programmed desorption of ammonia. The dehydration activity depends on treatment temperature on the catalyst precursor; the catalyst treated at 800 °C exhibits the best result with 100% glycerol conversion and more than 95% selectivity for useful products, including acrolein (64%), acetaldehyde, acetic acid and hydroxyacetone. We observed that the addition of molecular oxygen into reaction could greatly reduce the selectivity for by-products from 20% to 4% and can avoid coke formation. The dehydration activities of the catalysts were correlated with the characteristics of the catalysts.

Vanadium pyrophosphate oxides prepared by treating VOHPO4·0.5H2O at high temperature were investigated in glycerol dehydration with adding oxygen. The sample treated at 800 °C exhibits the best result with 100% glycerol conversion and more than 95% selectivity for useful products, including acrolein, acetaldehyde, acidic acid and hydroxyacetone. The addition of oxygen avoids coke formation and reduces side reactions.Figure optionsDownload high-quality image (70 K)Download as PowerPoint slide