Conversion of glycerol over vanadium supported beta zeolite: Role of acidity and alkali cations

Different vanadium supported beta zeolites modified with Cs and K, were used as catalysts for the conversion of glycerol, in gas phase, without any external reductant. The catalytic data show that all the catalysts studied are active in the conversion of glycerol and that the presence of vanadium oxide species promotes the formation of allyl alcohol. Moreover, modification of the vanadium-based catalysts with Cs or K changes the vanadium species and puts in evidence the importance of the acidity in this process. A low density of acid sites favors the formation of allyl alcohol, in detriment of acrolein one. The data also indicate that the formation of these compounds is closely related and could be explained using the same mechanistic path. • Vanadium oxide species promote the direct formation of allyl alcohol from glycerol. • The catalytic behavior depends on the acidity and presence of alkaline metals. • Formation of allyl alcohol and acrolein is intimately related