Photo-Induced Copper-Mediated Acrylate Polymerization in Continuous-Flow Reactors

The synthetic scope of photo-induced copper-mediated polymerization (photoCMP) in continuous-flow reactors is further explored. A series of monomers, namely, methyl (MA), ethyl (EA), n-butyl (nBA), 2-hydroxyethyl (HEA), and di(ethylene glycol) ethyl ether (DEGA) acrylate are investigated, all showing high livingness (dispersity in the range of 1.1 and linear first order kinetics) in the polymerizations and high conversions within 20-min reaction time. Next to the commonly used solvent (dimethyl sulfoxide [DMSO]), also a water-ethanol mixture was used as greener alternative, without any loss in reaction control. Upscaling the reactor from 2 to 16 mL allows for production of over 200 g of high-definition material (3000 g/mol, 1.1 dispersity) in overnight operation (18 h), demonstrating that the photoprocess can be run under very stable conditions even for extended reaction times. Via coupling of two reactors, direct chain extension of copolymers in a single reaction step is also demonstrated.