[Control of Heterogeneous Flow Reactions Using a Taylor Vortex Flow Reactor]

To advance the manufacturing of drug substances under continuous flow conditions, homogeneous reaction systems are usually favored to enhance process control. However, heterogeneous reaction systems also need to be controlled in pharmaceutical production because drug substances are synthesized through multiple steps in various reaction systems. In this review, the author discusses a technological platform based on the Taylor vortex flow reactor which comprises a cylindrical tube and a rotating shaft, to streamline control of heterogeneous reaction systems. In the first example, the nucleation timing of reactive crystallization could be both accelerated and precisely controlled using a Taylor vortex flow reactor with high shear stress. This approach successfully mitigated adhesion to the reactor walls, thereby preventing clogging. In the second example, Taylor vortex flow reactors were applied to both liquid-liquid biphasic alkylation and continuous crystallization. Integration of these applications enabled achievement of overall continuous manufacturing in a single step. These examples confirm the high versatility and scalability of the Taylor vortex flow reactor for controlling heterogeneous reaction systems under continuous flow conditions.