Abstract

The HANU-Reactor: Development of a Scalable Continuous-Flow Photoreactor

Hannes Gemoets, R&D Engineer, Creaflow

In the last decade, continuous-flow photochemistry has received much attention from researchers in academia as well as industry. With the groundwork now in place, the focus has been shifted to the realization of scalable photochemistry, and in this context, the HANU-reactor was developed. This pulsating-flow plate reactor contains static mixing elements that induce a split-and-recombine flow path, and is equipped with a large window lid for maximum light exposure. The synergetic use of the reactor geometry with a pulsating flow regime, results in plug flow behavior combined with intense mixing, regardless of its net flow rate. The innovative design allows the user to operate the reactor at both short and very long light exposure times, without compromising the mixing efficiency or the need for flow recirculation. To demonstrate its potential, an intramolecular [2+2]-cycloaddition was performed, producing an impressive 2.3 kg of Cookson’s diketone per day, utilizing a single 15 mL lab-scale HANU-reactor. Thanks to the innovative design, the HANU-reactor can be linearly scaled. Preparative photochemistry is now readily accessible by simply widening its process channel without the need to change any process parameters.[4] In addition, the pulsatile flow expands the window to heterogeneous reaction processing (e.g. heterogeneous photocatalyst). Furthermore, the window lid allows visual inspection as well as application of non-invasive, through-window inline spectroscopic PAT.