Polyethylene glycol (PEG) was impregnated on a palladium metal supported on silica gel and used in a catalyst for hydrogenation of benzaldehydes In the vapor-phase flow reaction the PEG modification improved catalytic activity and selectivity for a partially hydrogenated product benzyl alcohol In isoprene hydrogenation selectivity for partially hydrogenated products monoenes was also enhanced X-ray photoelectron spectroscopy (XPS) analysis of the modified catalysts revealed that the modification with PEG makes the palladium surface negatively charged possibly leading to an Increase in the selectivity for the partially hydrogenated product caused by enhancement of its desorption from the surface In the liquid-phase hydrogenation of benzaldehyde the PEG modification also Increased the selectivity for benzyl alcohol (C) 2010 Elsevier Inc All rights reserved