Abstract

Photochemistry as an Enabling and Scalable Tool

François Lévesque, Associate Principal Scientist, Merck & Co.

The past ten years have seen the exponential growth of reactions promoted by visible and UV light. This has led to the discovery of very useful and highly selective transformations that were not feasible without the use of photons. Due to the unique advantages of these reactions, we foresee an increasing use of photochemistry chemistry in the synthesis and production of API. Scaling-up these reactions remains a key challenge. As most photochemical reactions require a high surface area to volume ratio for good efficiency, the utilization of these transformations on large scale is most amenable to flow.  Our discussion will highlight the key parameters that need to be taken into account for an effective transition from the lab scale to preparative scale, namely geometry of the reactor, light source, photon density, path length, and residence time. Ongoing efforts by the flow chemistry team at Merck & Co., Inc. toward developing scalable photochemical reactions in flow and their application in specific case studies will be presented.