When: 17 March 2021, 14:00 – 16:00 GMT
A joint virtual meeting between the Applied Catalysis Group (ACG) and UK Catalysis Hub based around the theme of applied characterization.
Janelle Steves (GSK)
HTE in 3D
High-throughput Experimentation (HTE) offers the opportunity to explore expansive reaction space in a plate-based format. With the power to exponentially increase productivity compared to single reaction experiments, a chemist must judiciously choose which reaction parameters to evaluate in a HTE array. While this is not a completely empirical exercise, empiricism is often embedded in these designs in effort to span diverse reaction space. Our current workflow often stacks the deck with catalysts and reagents most likely to produce positive results based on literature data and our chemical intuition. Therefore, negative screening outcomes are often discarded upon analysis of results. Herein, we present an alternative analysis of HTE results from a Pd-catalyzed cross-coupling reaction using phosphine ligand steric and electronic descriptors obtained from quantum chemical calculations. This analysis models the trends in reactivity of the ligands across the entire series of positive and negative outcomes and provides insight into how phosphine ligand may influence reactivity and selectivity. Application of these steric and electronic descriptors to the design of new screening plates for Pd-catalyzed cross-coupling reactions will be discussed.
David Lennon (Glasgow)
Towards developing structure/reactivity relationships for elevated temperature operation of ultra-selective aniline synthesis catalysts
The heterogeneously catalysed hydrogenation of nitrobenzene to synthesize aniline is a key reaction in the process chain to produce isocyanates, materials used in the production of polyurethanes. Reflecting the complexity of large-scale isocyanate manufacture, the reaction is typically undertaken within an integrated chemical complex . This scenario then provides the opportunity to utilise the significant quantities of heat associated with the hydrogenation reaction (-443 kJ mol-1 !) to raise super-heated steam, which can then be employed as an energy vector within the particular chemical complex. This exercise in novel sustainable chemical manufacturing requires the hydrogenation reaction to be conducted at elevated temperatures, a condition that can compromise aniline selectivity.
This presentation will describe a collaboration with Huntsman Polyurethanes to develop structure/activity relationships for a series of alumina-supported palladium catalysts specified to deliver high aniline selectivity at elevated temperatures (T>100°C). Importantly, certain catalyst formulations were observed to favour different distributions of by-products, complicating exploitation of the intended step-change in industrial practice. Read more
Ben Deadman (ROAR)
Reaction Characterisation at The Centre for Rapid Online Analysis of Reactions (ROAR)
There are recognized deficiencies in the current pool of reaction data which are hindering the progress of synthetic chemistry towards becoming a predictive science. Over a century of synthesis has yielded a vast library of reactions but there is a pressing need for more comprehensive data sets which include negative results, multiple time-point reaction data, and interoperable synthesis procedures. The Centre for Rapid Online Analysis of Reaction (ROAR) is a new facility which brings together high-throughput (HT) batch and flow reactor platforms, in situ analytic technologies, and automation expertise to enable data-centric research in synthesis. In this talk we will demonstrate how ROAR can help characterise reactions using a case study of the catalytic reductive amination reaction.
Paul Collier (JM)