Abstract
The heterogeneously catalyzed hydrogenation of acetophenone (AP) was investigated in i-propanolic solution using Ru5%/Al2O3 as a catalyst. The catalyst was characterized by x-ray diffraction, BET surface area measurements as well as, with respect to its acidity, by Diffuse Reflectance Infrared Fourier Transformation Spectroscopy (DRIFTS) of adsorbed pyridine. The reaction was zero-order in AP with no products other than 1-phenylethanol (PE), acetylcyclo-hexane (AC) and 1-cyclohexylethanol (CE) detected. The overall order of reaction with respect to hydrogen pressure was 2.5 for the total consumption of AP, 2.8 for the formation of AC and 1.7 for the formation of PE. The kinetic results of AC formation could be modeled successfully assuming the adsorption of AP and hydrogen to take place on different catalytic sites (support and metal, respectively). In the case of PE formation (hydrogenation of the carbonyl group), competitive as well as noncompetitive adsorption of hydrogen and AP are believed to take place in parallel and were both drawn to discuss the kinetic results of PE formation.