Acrolein was hydrogenated over unsupported Pd, Pt and PdPt bimetallic catalysts with different Pd:Pt atomic ratios. The formation of saturated aldehyde (propanal) by C=C bond hydrogenation was the main reaction on each catalyst. Maximum conversion values were reached at 293 K over each palladium containing catalyst and at 473 K on Pt. palladium and platinum behaved differently in secondary reactions. Dipropyl ether was formed in the presence of Pd, while under the same conditions - low temperature (323 K) and high hydrogen pressure (400 Torr) - propane and propanol were produced on the Pt catalyst. The selectivity patterns of bimetallic catalysts were different from those of monometallic ones: Linder the same conditions dipropyl ether showed a higher selectivity on the Hilt pairs. As the surface Pt concentration increased, the Pt-like character was more and more prevailing: namely the selectivity of propane and propanol increased. At high temperature (473 K) acrolein underwent hydrogenolysis Over each catalyst. The selectivity of ethane was higher when Pd Was present. (c) 2008 Published by Elsevier B.V.