Orderly cascade of immobilized-enzyme catalysis and photocatalysis for continuous-microflow production of 2-phenylbenzothiazole

Abstract

Green, economic, efficient, and sustainable synthesis of 2-phenylbenzothiazole (2-PBZ)—an important versatile scaffold—remains challenging. Here, for the first time, we propose to cascade immobilized enzyme catalysis and photocatalysis in a continuous-microflow manner to realize the online reuse of the enzyme, eliminate cross-inhibitions between the two-step reaction processes, provide stronger and more uniform illumination, and enhance process efficiency. This novel microflow system required only 4.6 min of the total residence time to achieve >99% product yield, and 93.7% of the total catalytic activity was retained after running for 300 min. This orderly cascaded continuous-flow microreactor system widens the limitations of photo-biocatalytic approaches and provides the potential foundation for the industrial green production of 2-PBZ.