Toolbox study for application of hydrogen peroxide as a versatile, safe and industrially-relevant green oxidant in continuous flow mode

Hydrogen peroxide embodies an ideal oxidant in terms of atom-economy, availability and green metrics. However, its use has been limited because of risks associated with disproportionation and the exothermic potential of oxidizing reaction mixtures. This study aims to showcase the versatility of hydrogen peroxide in a range of oxidations, while ensuring that such processes operate practically and with a defined and minimized risk. To offset the hazards of using peroxides, continuous-flow equipment was utilized to limit the volume of unquenched peroxides and to maintain process control. A methodological approach was established relying on kinetic and calorimetric understanding. Finally, scalability was highlighted in an organocatalysed heterocyclic N-oxidation using a cascade of stirred tank reactors with nitrogen flushing.