ABSTRACT
Combinatorial methods and high-throughput experimentation (HTE) have resulted in successful discoveries of drugs1-3 and new materials.4-7 Many laboratories in industry and academia have started to apply combinatorial methods to catalytic research.7-18 Interestingly, one of the first applications of high-throughput techniques was precisely in the field of catalysis. In a review article written in 1950,19 A. Mittash relates that in the search for an ammonia synthesis catalyst “One of my associates developed a laboratory scale reactor which makes it possible to work easily at pressures of 100 odd atmospheres, a reactor of which we soon have two dozen and more in continuous operation.” The year was 1909! Mittash wrote that due to the lack of knowledge in the field, “a purely empirical search for suitable catalysts has to be employed …, and that he and his associates had to carry out about 20,000 small scale tests and to investigate 3000 preparations as potential catalysts” completed in a period of 2 years – nearly 100 years ago! It is interesting that in the recent rediscovery of the high-throughput methodology only in a few articles is it recognized that such an
empirical approach was the norm in industrial research in the past. In fact, it has been the authors’ experience that parallel reactors are ubiquitous in industrial laboratories. The new twist in this area is the miniaturization of the reactors and advances in analytical detection systems that have given the field new impetus. In 1986 there was an article describing a parallel microreactor20 that preceded many of the parallel reactor systems reported in the last 5 years. It is also interesting that some researchers report the use of high-throughput techniques to test 1000 catalysts a day without much consideration of pre-existing knowledge, whereas those who invented HTE lamented that the lack of pre-existing knowledge forced them to proceed in such a brute force approach. While the success of Mittash’s work was truly remarkable, we should not forget that it was all initiated by Haber’s insight into thermodynamics that led him and Mittash to realize that high pressure was the key to increasing the yield. So, even though the knowledge of catalysis was almost non-existent at the time, thermodynamics was sufficient to guide the experimentalists in the proper path of discovery.
