Hydrothermal synthesis of Mo-V mixed oxides possessing several crystalline phases and their performance in the catalytic oxydehydration of glycerol to acrylic acid

摘要

Graphical abstractDisplay OmittedHighlights?Acrylic acid was the main condensed reaction product.?Mo4.65V0.35O14crystallographic phase enhanced catalytic performance.?Catalytic reactions under pure O2showed the best results.?V4+/V5+equilibrium was crucial for maximizing selectivity towards acrylic acid formation.AbstractThe one-step oxydehydration of glycerol to acrylic acid over molybdenum and vanadium mixed oxides was investigated. The Mo-V oxide catalysts were prepared by a simple hydrothermal method under different synthesis and calcination atmospheres and were characterized byin situXRD, TPD-NH3, N2adsorption/desorption, X-ray absorption near vanadium K-edge spectroscopy and thermogravimetry. The catalytic performance of the samples at different temperatures (290, 320 and 350°C) and under different gas flow compositions (20% O2in N2, 100% O2, or 100% N2) revealed that the arrangement of the crystallographic structures of the active phases directly influenced the catalytic performance. It was found that the catalysts heat-treated in oxidizing atmosphere gave superior catalytic results comparing with the catalysts heat-treated in inert atmosphere due to the equilibrium between the crystalline phases MoVO5and Mo4.65V0.35O14that contains V+4and V+5. Catalytic oxydehydration at 320°C under a flow of 100% O2gave the best performance, achieving selectivity of 33.5% towards acrylic acid and 100% conversion of glycerol.]]>