Platinum, palladium, and copper catalysts supported on precipitated silica have been studied for the hydrodeoxygenation and hydrogenation of 2-methyl-2-pentenal in the 200-400 degrees C temperature range. The activity follows the order Pt > Pd > Cu. It has been found that at low temperatures, Pt and Pd are primarily active for the hydrogenation of the C=C bond to make 2-methyl-pentanal, with some decarbonylation, yielding n-pentane and CO as products. Decarbonylation increases at higher temperatures. Cu catalyzes hydrogenation of both C=C and C=O bonds. In both cases, the initial products are further hydrogenated to form 2-methyl-pentanol at higher space times. At higher temperatures on Cu, the hydrogenolysis of 2-methyl-pentanol takes place, giving 2-methyl-pentane (and H2O) as the dominant product while no decarbonylation is observed. (C) 2009 Elsevier Inc. All rights reserved.