A COMBINED APPROACH TO CHARACTERIZATION OF CATALYTIC REACTIONS USING IN-SITU KINETIC PROBES

Several in situ probes for continuously monitoring rate of catalytic r eactions under reaction conditions are described. They are reaction ca lorimetry, measurements of hydrogen uptake in the case of hydrogenatio n, and infrared spectroscopy. In studying catalytic hydrogenation reac tions, for example, these in situ probes provide kinetic details of th e reactions from different perspectives over the entire course of the reaction. The reaction calorimetry and the hydrogen uptake measure dir ectly, continuously and in a non-invasive manner the rate of reaction, while the in situ infrared spectroscopy provides time-resolved compos itional information in the liquid phase. A combination of the informat ion thus obtained leads to a clear and coherent kinetic picture of the reaction under study which can greatly facilitate pathway analysis an d mechanistic description of the catalytic reaction. in this report, t he usefulness of the combination of these in situ probes is illustrate d with two examples of heterogeneously-catalyzed hydrogenation reactio ns.