Membrane Reactors Accelerate Polymer Photosensitizer-Based Singlet Oxygen Reactions

Polymer photosensitizers have gained a growing interest as singlet oxygen (O-1(2)) generators. Although they provide a route to sustainable chemistry, their efficiency in bulk reactions is restricted by a limited oxygen supply and a short lifetime. Herein, we report membrane reactors that support a range of organic reactions using O-1(2) generated from polymer photosensitizers. The porous nature of the membrane support, a nylon fabric membrane functionalized with poly(fluorenthiophen thiadiazothiophen) (PFOTTzT), allows highly efficient trapping of a thin membrane of reagents that is in close proximity to the O-1(2) source. We demonstrate that oxidation reactions are accelerated by 10 - 100 folds, and polymerization reactions are rapidly initiated and accelerated and reach a nearly 2-fold increase in the degree of polymerization. The method is compatible with a range of solvents upon protection of the polymeric photosensitizers with a porous layer of polytetrafluoroethylene (PTFE) fabric that prevents solvent transport but allows O-1(2) diffusion through. Summarizing, our membrane reactors are sustain-able, low-cost, robust-in-use and overcome current limitations in reactions involving O-1(2) from polymer photo-sensitizers and show strong potential for green industrial use.