Experimentally Validated 3D-CFD Analysis of Continuous-Flow Reactor Configurations for the Electrochemical Trifluoromethylation of Caffeine

Abstract

Electrochemistry for producing pharmaceuticals has been gaining prominence in recent times as it offers a safer, greener, and cheaper alternative to conventional approaches for some key and difficult synthesis steps, such as trifluoromethylation. However, commercial application of the nanoparticle to a continuous manufacturing facility has many challenges. In this work, we develop 3D high-fidelity CFD models of various electrochemical reactor geometries for the trifluoromethylation of caffeine. The developed model is validated with in-house continuous flow trifluoromethylation experiments. The impact of the various process variables, such as the electrode gap, residence time, reactant inlet concentration, pulsation frequency, and duty cycle, on system performance is investigated in terms of yield, selectivity, and productivity. Several reactor configurations are analyzed, such as flat parallel plates, annular, serpentine channels, spiral, and 3D-printed electrodes. We find that the electrode gap and residence time greatly impact the system performance. Lower electrode gaps and longer residence times correlate to higher productivity. The 3D-printed electrode system was found to give a higher product yield compared with a flat electrode system. Furthermore, our CFD results show that employing spiral paths and serpentine channels offers a higher selectivity (up to 0.41) and enhanced productivity (increment of 23% compared with flat parallel plates).