A combined approach to characterization of catalytic reactions using in situ kinetic probes

Several in situ probes for continuously monitoring rate of catalytic reactions under reaction conditions are described. They are reaction calorimetry, measurements of hydrogen uptake in the case of hydrogenation, and infrared spectroscopy. In studying catalytic hydrogenation reactions, for example, these in situ probes provide kinetic details of the reactions from different perspectives over the entire course of the reaction. The reaction calorimetry and the hydrogen uptake measure directly, continuously and in a non-invasive manner the rate of reaction, while the in situ infrared spectroscopy provides time-resolved compositional information in the liquid phase. A combination of the information thus obtained leads to a clear and coherent kinetic picture of the reaction under study which can greatly facilitate pathway analysis and mechanistic description of the catalytic reaction. in this report, the usefulness of the combination of these in situ probes is illustrated with two examples of heterogeneously-catalyzed hydrogenation reactions.