Microreaction and membrane technologies for continuous single-enantiomer production: A review

ABSTRACT Microreaction and membrane technologies offer optimal conditions for controlling enantiomer synthesis and purification processes in continuous production, with numerous advantages over batch manufacturing. One of the many forces driving the development of such technologies for the production of single optical isomers is the need for enantiomerically pure pharmaceutical drugs because enantiomers may display opposite therapeutic effects or different treatment efficacies and side effects. Yet, despite advances in asymmetric synthesis and separation techniques, preparing enantiomerically pure compounds remains a challenging task. Here, we review the progress in microfluidics and membrane chiral separation over the last two decades. In addition to describing and critically assessing the state of the art in both disciplines, we provide an overview of their beneficial properties and characteristics for developing technologies toward producing enantiomerically pure compounds. Concomitantly, we evaluate efforts to integrate synthesis and membrane separation into a microfluidic platform and pinpoint the limiting factors that must be overcome before these platforms can be fully deployed in the industry.