Study of Extraction and Recycling of Switchable Hydrophilicity Solvents in an Oscillatory Microfluidic Platform

One of the challenges in the development of green and sustainable chemical processing is solvent removal and subsequent replacement with another solvent in various steps of multistep syntheses, extraction, or purification. A promising alternative approach is the use of "switchable" solvents that change their properties on demand. The evaluation of the performance of switchable solvents in the entire extraction-recovery process, with a capability of efficient solvent recycling, is vital for their future applications. We report an oscillatory microfluidic platform to reproduce a complete cycle of CO2-mediated extraction and recovery of switchable hydrophilicity solvents, with the capability of solvent recycling. The evaluation of the efficiency of solvent extraction and recovery in the entire process is achieved within 1.5 h, with <15 μL of the solvent, without the formation of double emulsions, and with the capability to obtain the temporal information for each step of the process. The new methodology enabled time-, labor-, and cost- efficient screening of the performance and recovery of different switchable solvents, important for the development of new effective formulations and their use on industrial scale.