Gas phase oxidehydration of glycerol to acrylic acid over Mo/V and W/V Cross Mark oxide catalysts

Gas phase oxidehydration of glycerol over Mo/V and W/V oxide catalysts was investigated in a fixed bed reactor. The Mo/V and W/V oxide catalysts were facilely prepared by calcination method and characterized by XRD, XPS, Raman, and NH3-TPD techniques. In addition to MoO3 or V2O5, Mo6V9O40 was formed in Mo/V oxide catalysts. The presence of V in W/V oxide catalysts caused the formation of hexagonal or orthorhombic WO3 while monoclinic WO3 was formed in the absence of V component. For Mo/V oxide catalysts, Mo1V0.25 oxide catalyst gave the maximum acrylic acid yield of 20.1% and the maximum acetic acid yield of 20.8% at the reaction temperature of 300 degrees C. Ma(1)V(4) oxide catalyst gave the maximum acrolein yield of 28.8% at 300 degrees C. For W/V oxide catalysts, W1V0.25 oxide catalyst gave the maximum acrylic acid yield of 25.7% and the maximum acetic acid yield of 21.2% at 300 degrees C. However, pure WO3 catalyst gave the highest acrolein yield of 50.3% at 300 degrees C. The yields of CO and CO2 increased with increasing V content in both bimetal oxide catalysts. More Mo5+, W5+, and V4+ cations present in the bimetal oxide catalysts gave high catalytic oxidation activity. (C) 2014 Elsevier B.V. All rights reserved.