A scalable light-diffusing photochemical reactor for continuous processing of photoredox reactions

Abstract

In the last decade, photoredox catalysis has received a remarkable attention for its unique reactivity for synthesizing fine chemicals and active pharmaceutical ingredients. However, the coupled photon and heat generation of light sources create challenges for achieving a proper heat management of photochemical reactors, thus inhibiting large-scale applications. In this work, we proposed a strategy to decouple photon and heat using light guide plate (LGP) technology, and accordingly designed a continuous light-diffusing photochemical reactor (LDPR). In LDPR, the photons emitted from the edge light source are distributed uniformly on the top surface of LGP where the fluidic channels are located. This configuration isolates heat generation location from where photons are utilized, benefiting the heat management of the reaction zone. The photon flux of LDPR was characterized with a chemical actinometry method. Two important photocatalytic bond-forming reactions, α-amino arylation and C(sp2)–N cross-coupling, were demonstrated in LDPR with high efficiency. To show the scalability of LDPR, we increased the throughput via a hybrid strategy of scaling-up and scaling-out, achieving a continuous 10-gram synthesis of an α-amino arylation product.