Cloud-inspired multiple scattering for light intensified photochemical flow reactors

Abstract

The development of light-promoted organic synthesis has gained great momentum in recent years. However, the rates of photochemical reactions are dependent on the photon flux, which is typically limited by Beer–Lambert attenuation, and hampers their broad application in large-scale production. When photochemistry takes place inside clouds, photochemical reaction rates exceed clear-sky values due to the increased photon path lengths resulting from multiple reflections and refractions at droplet-air interfaces. Herein, by mimicking how nature accelerates photochemical reactions, we present a flow reactor scheme that utilizes the liquid–solid interfaces provided by densely packed glass beads as efficient light scatterers to enable homogeneous distribution and intensification of light absorption within the reaction media. With this design, we are able to scale up photo flow-reactors from micro-scale to meso-scale without compromising their performance.