Pd catalysts were investigated for the hydrogenation of 4-isobutylacetophenone (4-IBAP) and for Pd/SiO 2 an improved (compared with the non-patented literature) yield of nearly 80% of the desired product 1-(4-isobutylphenyl)ethanol (4-IBPE) was obtained. However, severe catalyst deactivation was observed. The spent catalyst was characterized using a wide variety of thermal (TGA, TPO-MS), microscopic (TEM), and spectroscopic (DRIFT, LEIS) characterization techniques. Pd leaching did not occur. Oligomerization of 4-IBAP by condensation reactions due to the acidity imparted by the presence of isolated silanol groups on SiO 2 is proposed as one of the causes of catalyst deactivation. Pd crystallite growth and strong chemisorption of the H 2 O liberated by 4-IBPE hydrogenolysis also contributed to the loss of catalytic activity. The conclusions are supported by the high stability of Pd black in catalyzing the reaction.