Dehydration of glycerol was performed in the presence of various metallic catalysts including alumina, magnesium, ruthenium, nickel, platinum, palladium, copper, raney nickel, and copper-chromite catalysts to obtain acetol in a single-stage reactive distillation unit under mild conditions. The effects of operation mode, catalyst selection, glycerol-feed flow rate, catalyst loading, and initial water content were studied to arrive at optimum conditions. High-acetol selectivity levels (> 90%) were achieved using copper-chromite catalyst, and operating in semi-batch reactive distillation mode. A small amount of water content in glycerol feedstock was found to reduce the tendency for residue to form, therein extending catalyst life. The acetol from this reaction readily hydrogenates to form propylene glycol, providing an alternative route for converting glycerol to propylene glycol. (c) 2006 American Institute of Chemical Engineers.