Continuous flow processing of bismuth-photocatalyzed atom transfer radical addition reactions using an oscillatory flow reactor. Issue 7 (8th December 2020)

• Record Type: Journal Article
• Authors: Bianchi, Pauline; Williams, Jason D.; Kappe, C. Oliver
• Is Part Of: Green chemistry. Volume 23:Issue 7(2021)
• Page Start: 2685
• Page End: 2693
• Publication Date: 2020-12-08
• Subjects: Environmental chemistry -- Industrial applications -- Periodicals; Environmental management -- Periodicals; 660
• DOI: 10.1039/d0gc03070h
• Languages: English
• ISSNs: 1463-9262

Abstract

Abstract : An oscillatory flow photoreactor facilitates the use of Bi2 O3 as a green and recyclable photocatalyst for ATRA reactions. Abstract : Metal oxides represent an abundant and non-toxic class of photocatalysts for organic transformations. However, their use in larger scale processes is complicated by incompatibilities with continuous flow processing – a proven scale-up route for photochemistry. We detail the development of an efficient atom transfer radical addition protocol using a sustainable solvent system (acetone : PEG 400) and a low loading (2 mol%) of Bi2 O3, which can be handled in an oscillatory flow reactor. Optimization of the reaction and oscillatory parameters led to high throughput (36 g in 4 h, 89% yield, 599 g L −1 h −1 ), with a process mass intensity (PMI) of just 8.5. The process also facilitates high recyclability (3 cycles with no loss of yield), and was demonstrated to be applicable to a range of other substrates on multigram scale, in moderate to excellent yields.