Strategies for Library Design and Testing

For choosing suitable chemical compositions of the libraries, two extreme strategies seem to be possible One approach would focus fully on such elements in the periodic table which are known to be active for a certain class of reactions. For a partial oxidation reaction, one would use vanadium, molybdenum, bismuth, antimony, etc., to create the library. However, for the interesting catalytic processes in which an HTE approach would be most useful, many hundred person-years have already been spent in the development process, though without success. This means that many of the obvious combinations of elements have already been tested. A systematic scanning of the composition range might lead to active catalysts, but the chance to find a fundamentally new catalyst seems to be limited. 

The second extreme strategy would be to neglect totally anything which is known in heterogeneous catalysis and randomly to scan combinations of elements in the periodic table. However, this approach does not seem to be very useful, since by this procedure one would, for instance, combine elements that form volatile compounds under reaction conditions which would then ruin the whole library and not be useful under industrial conditions. In addition, the price and availability of certain compounds might restrict the fully randomized approach. 

Schiith, Hoffmann, Wolf, Schunk, Sticherl and Brenner 

We consider that the best approach is one which combines the two extremes. Formulations should in most cases be based on elements known to be active in catalysis in a broad sense, but with the addition of non-obvious components in order to create non-obvious formulations. Only such a strategy would create the chemical diversity which increases the chances to discover something fundamentally new. 

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