Micropillar-based aqeous-organic continuous liquid-liqiud extraction device with very long residence times for the extraction of pharmaceutical compounds

We present for the first time a liquid-liquid extraction (LLE) device that allows parallel aqueousorganic system extractions with residence times over 4 min. In our device, a series of micro-pillars placed in the extraction channel stabilizes the co-flowing immiscible streams, offering operation of the device both at high and at very low flow rates. This significantly enhances the applicability of microfluidic devices to investigate and achieve optimal extraction conditions. In this contribution, we demonstrate high extraction yields of acetophenone, an aromatic ketone which is used as a pharmaceutical intermediate for a diverse range of pharmaceuticals. Furthermore, we characterize the device design with regard to fluid properties, hydrodynamic and transport phenomena and discuss experimental extraction data. Such comprehensive understanding will in the future facilitate the definition of operating conditions for the continuous extraction on microlitre and industrial scale, and thus accelerate the uptake of microfluidic devices in the bioprocessing industry.