A Screening Workflow for Synthesis and Testing of 10,000 Heterogeneous Catalysts per Day – Lessons Learned

Abstract

Summary: For some years now a trend toward the employment of high‐throughput technologies in the development of new catalysts has been apparent in academic and industrial research. One reason is the unmanageably large parameter space present in heterogeneous catalysis, which implies that an increase in throughput in the preparation and testing of candidate substances is necessary, in order to be able to identify a new catalyst in a practicable amount of time. We have tried to locate the current boundaries in achievable throughput. To this end, we developed a workflow in which 10,000 substances per day were synthesised and their activity tested in a heterogeneously catalysed gas phase reaction (alkene epoxidation). The substances were synthesised by dosing precursor solutions onto a single substrate, using ink‐jet printer technology and subsequent thermal treatment. For the activity testing, the product stream of each candidate was conducted through a detection layer, where the target product was converted into a fluorescent substance. By locally resolved fluorescence spectroscopy a rough assessment of each candidate was possible. Because a throughput of 10,000 substances per day is still not able to map the whole parameter space in a practicable amount of time, we used a combination of evolutionary optimisation and data mining as our experiment design strategy for the reduction of the experimental parameter space. It became apparent that a throughput of 10,000 substances per day was only possible at the cost of abstraction and simplification with a concomitant reduction in knowledge gain per individual experiment. Because not every reaction is suited to be simplified in such a manner, whether a high‐throughput screening approach is effective or not has to be considered on a case by case basis.Methods of synthesis and testing to achieve a throughput of 10,000 catalysts per day.magnified imageMethods of synthesis and testing to achieve a throughput of 10,000 catalysts per day.

Application of Data Mining and Evolutionary Optimization in Catalyst Discovery and High‐Throughput Experimentation – Techniques, Strategies, and Software

“…For example, application of subgroup search techniques or decision trees could be helpful for data analysis in a large parameter space with only a few data sets (e.g., if the number of parameters is greater than the number of data sets). On the other hand, to avoid combinatorial explosion in the experiment design in large parameter spaces and also in the presence of discrete variables, an evolutionary experiment design could outperform a classical statistical design [3].…”

“…In a previous paper we described the problems and the boundaries of possible throughput in the discovery of novel catalysts in considerable detail (ref. [3] and citations therein).…”

“…Again, as we started, no commercial system was available which could solve our demands or fulfill our requirements. Therefore, we decided to develop an own platform of algorithms and extended data-based technologies to combinatorial catalyst discovery at Bayer [3].…”

High Throughput‐Experimentation in der Materialforschung und Prozessoptimierung

“…Es hat sich jedoch gezeigt, dass die Durchführung von 10 000 Experimenten auf konventionelle Art weit mehr Informationen generiert, als der von uns verwendete Ansatz [11].…”

High-Throughput Materials Discovery by Inkjet-Printing of Composition Spread Libraries

“…Later the catalysts synthesis method from metal nitrates in the presence of citric acid has been extended to smaller catalysts amounts (0.1 -1mg) and a higher number of library members (10,000 catalysts a day) in a conceptual paper by Duff et al from Bayer Technology Services also addressing the mixing problem. 7 The group applied hydrophobization of a porous substrate to avoid chromatographic effects, which tend to inhibit droplet mixing. In this paper we describe the preparation of libraries through inkjet printing by a related sol-gel recipe with polymeric ester formation with the intention to find routes for continuous compositions spread library synthesis.…”