Highly Efficient Conversion of Glycerol to Acetaldehyde Over In2O3/HZSM-5 Catalysts

The dehydration of glycerol, a major byproduct from biodiesel production, is a key step for the production of acetaldehyde. However, the selectivity toward acetaldehyde is presently not satisfactory. In the present work, In2O3 supported on the HZSM-5 zeolite was prepared by a simple impregnation method and applied as a tandem catalyst for glycerol dehydration. Surprisingly, the 3%In2O3/HZSM-5(500) catalyst exhibits a high selectivity to acetaldehyde of 80% with a glycerol conversion of 100% at a reaction temperature of 340 °C. The characterization results showed that the amount of total acidity and Brønsted acid sites decreased, while the amount of Lewis acid sites increased, after the introduction of In2O3 into the HZSM-5(500) zeolite, which is responsible for the high selectivity to acetaldehyde.