The control of selectivity in gas-phase glycerol dehydration to acrolein catalysed by sulfated zirconia

This paper is about the synthesis of acrolein by means of glycerol dehydration in the gas phase, catalysed by sulfated zirconia. The reaction parameters affecting glycerol conversion and selectivity to acrolein, the contribution of homogeneous reactions and roles of co-fed oxygen and of diffusion constraints were examined, in relation to the complex reaction network. The best selectivity to acrolein, 42% obtained at 49% glycerol conversion, was achieved by combining conditions that limit the occurrence of consecutive reactions from acrolein, leading to acetaldehyde and to heavy compounds, whilst minimizing mass-transfer inter-particle limitations. These findings are of general interest in relation to both the transformation of glycerol into acrolein by means of gas-phase dehydration, and the use of sulfated zirconia catalysts for high-temperature acid-catalysed reactions.