Flow photochemistry — from microreactors to large-scale processing

Photochemistry in Pharmaceutical Development: A Survey of Strategies and Approaches to Industry-wide Implementation

“…This last point goes hand in hand with the historical “photochemistry cannot be scaled” misconception, and over the last two decades this has been a stigma when discussing the technology. The literature of the last 100 years discusses the issues with photochemistry and how to overcome them, highlighting merits of both batch and flow reactors. ,− With the advent of the publication of “A Practical Flow Reactor for Continuous Organic Photochemistry” by Booker-Milburn and Berry in 2005 coupled with widely available nearly monochromatic light sources in the 310–800 nm range, i.e., light emitting diodes (LEDs), − this has transformed photochemistry from a seldom-used bond-forming strategy into an innovative technology . Recently, Bonfield et al (2020), Cohen et al (2023), and Callard-Langdon et al (2023) discussed scaling photochemistry in the pharmaceutical industry.…”

On a seamlessly replicable circular photoreactor for lab-scale continuous flow applications

“…[22][23][24][25] These varied approaches have served as the foundation for developing both custom-built and commercial photoreactors, each differing in their unique approach to provide mixing and maximization of photon flux while minimizing light loss. 26,27 These systems exhibit differences not only in the cooling mechanisms employed to prevent light source overheating, but also in the thermoregulation of the reactor and selection and placement of the light source with regard to the reactor. [25][26][27] While continuous flow systems offer notable advantages, high costs associated with commercial continuous flow systems often divert researchers to familiar batch options, relying on readily available equipment.…”

Multimode Photo-CSTR (Continuous Stirred Tank Reactor) Setup for Heterogeneous Photocatalytic Processes

“…The inclination of clogging in flow reactors and the attenuation effect of photon transport pose challenges . This becomes especially problematic with larger reactor dimensions or increased amounts of solids . Batch and semibatch processes are frequently applied in the pharmaceutical field, , involving stoichiometric solids in the form of reagents, intermediates, byproducts, or products.…”

“…8 This becomes especially problematic with larger reactor dimensions or increased amounts of solids. 9 Batch and semibatch processes are frequently applied in the pharmaceutical field, 10,11 involving stoichiometric solids in the form of reagents, intermediates, byproducts, or products. The flow of suspensions in pipelines, with a large-scale continuous solid particle transport, has been reported in centimeter-or meterscale tubes.…”