Process Intensification of Photochemical Oxidations using a High Throughput Rotor-Stator Spinning Disk Reactor: A Strategy for Scale Up

This paper presents a novel high-throughput reactor for intensification of photochemical conversion processes. The photocatalyzed gas-liquid oxidation of α-terpinene to the drug ascaridole with rose-bengal was achieved with throughputs of over 1 kg∙day-1 (71 kg∙day-1∙m-2) under visible light irradiation. The performance of the reactor is correlated to rotation speed, liquid flowrate, gas flowrate, catalyst concentration, substrate concentration, gas holdup, gas bubble size, and energy dissipation rate. The conversion and selectivity increase from 37% to 97% and 75% to 90% respectively with an increase of rotation speed from 100 to 2000 RPM. Compared to conventional photochemical reactors such as the batch reactor or the microreactor, the photo-rotor-stator spinning disk reactor has much higher productivity (270 mmol∙h-1 or 19.2 mol∙h-1∙m-2) and higher selectivity (> 90%), with the latter illustrating the impact of mixing on selectivity. The findings of this study can be used to study, design, optimize and scale photochemical processes using the rotor-stator spinning disk reactor.