Batch versus Flow Photochemistry: A Revealing Comparison of Yield and Productivity |
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Authors: | Dr Luke D Elliott Dr Jonathan P Knowles Dr Paul J Koovits Katie G Maskill Michael J Ralph Dr Guillaume Lejeune Lee J Edwards Richard I Robinson Ian R Clemens Brian Cox David D Pascoe Guido Koch Martin Eberle Malcolm B Berry Prof Kevin I Booker‐Milburn |
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Institution: | 1. School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS (UK);2. Novartis Institutes for Biomedical Research, Wimblehurst Road, Horsham, West Sussex, RH12 4AB (UK);3. Novartis Pharma AG, Novartis Institutes for Biomedical Research, 4002 Basel (Switzerland);4. GlaxoSmithKline, Gunnels Wood Road, Stevenage, Herts, SG1 2NY (UK) |
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Abstract: | The use of flow photochemistry and its apparent superiority over batch has been reported by a number of groups in recent years. To rigorously determine whether flow does indeed have an advantage over batch, a broad range of synthetic photochemical transformations were optimized in both reactor modes and their yields and productivities compared. Surprisingly, yields were essentially identical in all comparative cases. Even more revealing was the observation that the productivity of flow reactors varied very little to that of their batch counterparts when the key reaction parameters were matched. Those with a single layer of fluorinated ethylene propylene (FEP) had an average productivity 20 % lower than that of batch, whereas three‐layer reactors were 20 % more productive. Finally, the utility of flow chemistry was demonstrated in the scale‐up of the ring‐opening reaction of a potentially explosive 1.1.1] propellane with butane‐2,3‐dione. |
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Keywords: | batch reactors cycloaddition flow photochemistry rearrangement scale‐up |
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