Scalability of photochemical reactions in continuous flow mode

Abstract

Continuous flow photochemistry as a field has witnessed an increasing popularity over the last decade in both academia and industry. Key drivers for this development are safety, practicality as well as the ability to rapidly access complex chemical structures. Continuous flow reactors, whether home-built or from commercial suppliers, additionally allow for creating valuable target compounds in a reproducible and automatable manner. Recent years have furthermore seen the advent of new energy efficient LED lamps that in combination with innovative reactor designs provide a powerful means to increasing both the practicality and productivity of modern photochemical flow reactors. In this review article we wish to highlight key achievements pertaining to the scalability of such continuous photochemical processes. Graphical abstract

Dynamically triggering photoreactions for high performance and efficiency

“…The design of the photoreactor is mainly governed by the need to guide photons efficiently to the reaction solution. [20][21][22][23][24] In this context, the properties of the light source and the reactor, including the geometry and the wall materials, must be aligned such that as much photons as possible reach the reaction solution. Furthermore, spatial, temporal and spectral distribution of the intensity are defined by the reactor design.…”

The development of luminescent solar concentrator-based photomicroreactors: a cheap reactor enabling efficient solar-powered photochemistry

“…The 5 × 5 cm 2 LSC-PM design is, however, not suited for large-scale solar photochemistry. Scaling micro-and milliflow reactors in general, but even more so for photochemical applications, can be a challenging endeavour [11,13,59]. A suitable strategy for scaling up the LSC-PMs is numbering up of the reactor channels: distribution of the inlet process stream over several parallel reactor channels [60].…”

“…lightemitting diode (LED) technology) [9] and the development of scalable reactor technology (e.g. continuous-flow microreactor) [10][11][12][13][14][15][16]. Having access to affordable light sources and superior photochemical reactors, nothing was holding back chemists from implementing photochemical transformations in their work en route to complex and biologicallyactive organic molecules [17][18][19].…”

Continuous Flow Synthesis of Anticancer Drugs

“…Compared to batch manufacturing, continuous manufacturing offers higher quality products and less batch-to-batch variability because of the high control over reaction conditions (e.g., temperature, pressure, and reaction time). For the same reason, flow technology enables chemists to easily perform reactions that would be very challenging in batch mode [19] due to extreme conditions, such as high-and low-temperature conditions [20][21][22][23], high pressure [24][25][26], the presence of highly reactive and unstable intermediates [27], as well as photo-or electrochemical processing at scale [28][29][30][31][32]. The modular nature of this technology and the robustness of individual reactor components not only provide flexibility but also facilitate the expansion of the applications of flow reactors to different industrial processes, which can mitigate production-chain incidents [7].…”