The influence of MSI (metal-support interactions) on activity and selectivity in the hydrogenation of aldehydes and ketones

The vapor-phase hydrogenation of a group of aldehydes and ketones which contain unsaturated C=C bonds has been studied over a family of supported Pt catalysts. Turnover frequencies, activation energies and reaction orders for crotonaldehyde, benzaldehyde, phenylacetaldehyde and acetophenone are provided and compared to those for butyraldehyde, benzyl alcohol, 1-phenylethanol, acetyl-cyclohexane and acetone. Metal-support interactions (MSI) induced in Pt/TiO2 not only enhance specific activity but also markedly shift selectivity because hydrogenation of the carbonyl bond is favored. The retention of high selectivity to the intermediate unsaturated alcohols shows that adsorption properties, as well as kinetic parameters, are altered. A model is discussed which describes the sites responsible for this behavior.