The vapor-phase dehydration of 1,2-propanediol (1,2-PDO) was performed over various supported acidic oxide catalysts. Silica-supported WO3 catalyst shows the highest catalytic activity for propanal formation than other supported catalysts. A high and stable propanal selectivity of 93.5% was attained in H-2 atmosphere over 18.2%WO3-loaded silica catalyst using 20 wt.% 1,2-PDO aqueous solution as the reactant. The conversion of 1,2-PDO and the selectivity to propanal over the silica-supported WO3 were significantly affected by the calcination temperature of the catalysts. Since the high calcination temperatures decrease both the number of acid sites and the surface area of the catalysts, they decrease both the conversion of 1,2-PDO and the selectivity to propanal. The appropriate calcination temperature for silica-supported WO3 catalysts is 320 degrees C. The conversion of 1,2-PDO and the selectivity to propanal were also affected by the reaction temperature, the concentration of 1,2-PDO and the amount of catalyst used. A high propanal selectivity of 89.1% with a complete 1,2-PDO conversion was obtained at 250 degrees C over 3 g of 18.2% WO3-loaded silica catalyst when pure 1,2-PDO was used as the reactant. (c) 2014 Elsevier B.V. All rights reserved.