Catalysis of Organic..

488Profiling of Catalytic PerformanceBased on this approach, libraries of heterogeneous catalysts can be built up whichcover a wide range of fine-chemical application of solid catalysts from whichsuitable catalysts can be chosen rapidly.In this paper, principles and potential of the catalytic performance profiling isintroduced and illustrated with respect to the identification of a suitable Pd/C catalystfor selective hydrogenation of a hydroxy-olefin from a library of diverse palladiumcatalysts.R 11+ H22 3R 2R 3- H 2 OR 1 R 2 R 2R 3R 3+ H 2R 1HOHOHReaction scheme 1 (R1, R2 = alkyl)Results and DiscussionMethodology: In Figure 1 a) and b) the principles of catalytic profiling analysis areexplained: Catalytic profiling analysis includes a set of test reactions which are verysensitive with respect to catalyst properties and/or the recipes of preparation. Fromactivity and selectivity values measured for a set of test reactions (Fig. 1a) correspondingperformance profiles (Fig. 1b)) can be derived which can be understood ascatalytic fingerprints for individual catalysts. Thus, performance profiles allow a statisticalanalysis of similarities (Fig. 1b).Example for demonstration: The example shall demonstrate that a data base comprisingactivity data from hydrogenation of mono-functional substrates allows a preselectionof potential catalysts for hydrogenation of multifunctional substrates. Basedon this pre-selection concept the process of identifying the optimal precious metalpowder catalysts is accelerated.For proof of principle, a catalyst which leads to selective formation of saturatedalcohol according to reaction scheme in Figure 2 was identified among a group ofsixteen different Pd-catalysts prepared by different methods and showing differentmetal particle size, metal dispersion and oxidation state of Pd. For pre-selection ofpromising catalysts, profiling data concerning C=C double bond hydrogenation andhydrogenolysis are of interest. Activity data for hydrogenation of cinnamic acidwhich represents C=C double bond hydrogenation and debenzylation ofdibenzylether, which represents hydrogenolysis, were chosen as pre-selection criteriaand visualized by performance profiles (Fig. 3). The profiles refer to the followingactivity values:Hydrogenation of cinnamic acid(1) Activity of hydrogen conversion at reaction time t = 0Hydrogenation of dibenzylether(2) Activity for hydrogen conversion at reaction time t = 0(3) Activity for hydrogen conversion at reaction t = 80 min