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

• Glycerol oxidehydration was effectively catalyzed by Mo/V or W/V oxide catalysts.
• Mo/V or W/V catalyst had acidic and oxidative activities for oxidehydration reaction.
• Acid sites on catalysts catalyzed glycerol dehydration to acrolein and acetaldehyde.
• Mn+/M(n+1)+ pairs gave high oxidation activity for the formation of acrylic acid.

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 °C. Mo1V4 oxide catalyst gave the maximum acrolein yield of 28.8% at 300 °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 °C. However, pure WO3 catalyst gave the highest acrolein yield of 50.3% at 300 °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.

Gas phase glycerol oxidehydration was effectively catalyzed by Mo/V or W/V oxide catalysts. Mo/V and W/V oxide catalysts had acidic and oxidative activities for glycerol oxidehydration reaction. Acid sites on Mo/V and W/V oxide catalysts catalyzed glycerol dehydration to acrolein and acetaldehyde. Metallic cations with low valences in Mo/V and W/V oxide catalysts gave high oxidation activity for the formation of acrylic acid, acetic acid, CO, and CO2.Figure optionsDownload as PowerPoint slide