Vapour phase dehydration of glycerol to acrolein over NbOPO4catalysts

Abstract

BACKGROUND The valorization of glycerol obtained from biodiesel production is a challenging task. Effective use or conversion of crude glycerol to specific products will further reduce the cost of biodiesel production. RESULTS Vapour phase dehydration of glycerol to acrolein was investigated over solid acid catalysts containing nio-biumoxophosphate (NbP) by varying the calcination temperature. All the catalysts prepared were active for the synthesis of acrolein (conversion of glycerol was observed in the range 75–100% with selectivity to acrolein in the range 69–86%). The acidic properties are correlated with catalytic functionalities during dehydration of glycerol. CONCLUSIONS The NbP catalyst calcined at 550 °C has shown higher selectivity to acrolein with total conversion of glycerol. Calcination of the samples at 350 to 650 °C produces amorphous NbP sample, which contains significantly higher fractions of moderate acid sites than the crystalline NbP. The higher activity during glycerol dehydration and acrolein selectivity exhibited by NbP-550 catalyst is attributed to the presence of only moderate acidic sites with the majority of them Brønsted acidic sites. © 2013 Society of Chemical Industry