Scale-Up of a Heterogeneous Photocatalytic Degradation Using a Photochemical Rotor–Stator Spinning Disk Reactor

Abstract

Many chemical reactions contain heterogeneous reagents, products, byproducts, or catalysts, making their transposition from batch to continuous-flow processing challenging. Herein, we report the use of a photochemical rotor–stator spinning disk reactor (pRS-SDR) that can handle and scale solid-containing photochemical reaction conditions in flow. Its ability to handle slurries was showcased for the TiO 2 -mediated aerobic photodegradation of aqueous methylene blue. The use of a fast rotating disk imposes high shear forces on the multiphase reaction mixture, ensuring its homogenization, increasing the mass transfer, and improving the irradiation profile of the reaction mixture. The pRS-SDR performance was also compared to other lab-scale reactors in terms of water treated per reactor volume and light power input.

Dual role of benzophenone enables a fast and scalable C-4 selective alkylation of pyridines in flow

“…In addition, precipitation of the photocatalyst and the oxidant in the reaction coil was observed, which would lead to clogging problems over time. 12 We wondered if the highly-charged nature of TBADT could be an issue under these conditions, so we decided to switch to a simpler organic HAT mediator, such as benzophenone ( BP1 ). 13,14 Although similar low yields were obtained (Table 1, entry 2), a completely homogeneous solution was observed during the entire experiment.…”

Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor

“…Solid reagents and catalysts cause severe problems, such as reactor clogging under continuous-flow conditions. To prevent reactor fouling in (gas-)solid-liquid heterogeneous photoreactions, different solutions have been proposed [ 16 ], including the use of serial micro-batch reactors (SMBR, Figure 1a ) [ 17 ], rotor-stator spinning disk reactors ( Figure 1b ) [ 18 ], and the combination of oscillatory pumps with microstructured reactors ( Figure 1c ) [ 19 – 20 ].…”

Transesterification of Triglycerides in a Rotor–Stator Spinning Disc Reactor: Scale-Up and Solid Handling

“…Overall, in comparison to the thin film spinning disc reactor, several advantages have been found with RS-SDR, including higher specific heat and mass transfer rates as well as lower micromixing times. ,,− The key factor for this improvement is the high specific energy input to the reactor, which can be up to a factor 10 3 higher than conventional reactors. Researchers have utilized the high rates of heat and mass transfer to intensify various reactions/processes, including the epoxidation of methyl oleate, the oxidation of tertiary amines to amine N-oxides, chromium waste extraction, chlor-alkali processes, photochemical processes, , the esterification of free fatty acids, and the synthesis of BaTiO 3 nanoparticles . Additionally, the scale-up of thin film spinning disc reactors can be challenging due to the requirement of a fluid redistributor at each stage.…”