Liquid-phase heterogeneous catalytic hydrogenation of 2-butanone over Pt/Al2O3 was performed in anhydrous d(8)-toluene with on-line FTIR measurements and further perturbations of water. The hydrogenation rates of both 2-butanone and solvent d(8)-toluene were strongly affected by the presence of water and unusual spectral changes were observed after the perturbations of reactant and water. It is suggested that hydrogen bonding is responsible for the unusual spectral changes. The marked decrease in the reaction rates and the unusual spectral changes, taken together, seem to suggest that anhydrous experiments are important both for preparative studies as well as kinetic and mechanistic studies of the un-activated simple ketone hydrogenation over Pt/Al2O3 (i.e. 2-butanone) and should be implemented when possible. (C) 2007 Elsevier B.V. All rights reserved.