Selective Conversion of Glycerol to Acetol: Effect of the Preparation Method of CuAl Catalysts and Reaction Phase

A group of CuAl catalysts were synthesized with a Cu/Al molar ratio of 1:1 using different preparation methods: coprecipitation, surfactant assisted coprecipitation, polymeric precursor, and self-combustion and then screened for the selective dehydration of glycerol to acetol. The catalysts were employed in glycerol conversion at the same temperature (227 °C) in two different laboratory-scale systems, the first one at atmospheric pressure (gas phase) and the second one in a pressurized system at 34 absolute bar (liquid phase). The preparation method of the CuAl catalysts influenced the carbon yield to liquids and acetol selectivity. However, the reaction phase had a greater influence than the preparation method of the catalyst. In the gas phase, the carbon yield to liquids reached values above 40% and the carbon selectivity to acetol was higher than 90%. The highest acetol yield, 462.6 mgacetol/gglycerol, was obtained with the CuAl catalyst prepared by the surfactant-assisted coprecipitation method. This study provides a new perspective on catalyst design by highlighting the crucial role of preparation techniques in determining CuAl catalyst performance in the liquid and gas phases.