(699a) Scalable Photoreactors Using Intensified Wireless Micro LED Packed Beds

Photochemistry, the use of visible or ultraviolet light to initiate chemical reactions, is an electron driven reaction that is considered to be more efficient than traditional thermal driven chemistries. Despite this, its widespread adoption in the chemical industry has been limited because of difficulty in reaction scalability: 1) photochemical reactions are typically studied under batch conditions and are difficult to translate to flow, and 2) reactors cannot simply be scaled out because light penetration through a liquid medium decreases exponentially as the path length increases (Beer’s Law). The photoreactor designed in this work differs substantially in its approach in it is infinitely scalable in light penetration with <1 mm characteristic length without incurring hydrodynamic penalties typical in small channels. This ensures efficient photon transfer to the reactants. Wireless broad spectrum visible light LEDs (420 nm to 780 nm) were used as packing material inside the column of the reactor. Not only is the LED packing efficient at generating reactions, it also induces turbulence and mixing within the reactor. This is beneficial in multiphase chemistries. Alpha-terpinene, a precursor for the pharmaceutical ascaridole, was oxidized using air and a photosensitizer, Rose-Bengal.