(417d) A Versatile Polytetrafluoroethylene Membrane Separator for Microreactor Applications

Here we report the development of a simple, low-cost capillary-based membrane separation module for liquid-liquid phase separation and microextraction.^1,2 Designed specifically for microfluidic and microreactor applications, the separator comprises a length of microporous polytetrafluoroethylene (PTFE) capillary bonded to rigid PTFE capillary for direct coupling into a flow reactor. The separator is shown to provide highly efficient separation of aqueous-fluorous, aqueous-organic, and organic-fluorous segmented flows between 100 and 2,000 µL min^-1, and under a range of flow rate ratios, making it ideal for post-processing chemical syntheses performed in droplet and segmented flow microreactors.

We demonstrate that complete separation can be achieved for a range of liquid-liquid combinations by tuning the flow restriction at the separator outlet to account for differences in fluid viscosity and surface tension. Using the separator, we demonstrate the following flow processing operations: (i) inline spectroscopic analysis of the solvent phase in a solvent:carrier segmented flow process â?? where removal of the carrier phase circumvents the need for high speed detectors synchronized to the droplet/segmented flow; (ii) inline aqueous-organic product extraction; (iii) continuous recovery of a carrier phase from a solvent:carrier segmented flow process; and (iv) the ability to regenerate a stable segmented flow post-separation, and thereby facilitating inline processes that require a combination of continuous and segmented flow regimes, such as multistage purification.

(1) Bannock, J. H.; Phillips, T. W.; Nightingale, A. M.; de Mello, J. C. Anal. Methods 2013, 5, 4991â??4998.

(2) Phillips, T. W.; Bannock, J. H.; de Mello, J. C. Lab Chip 2015, 15, 2960â??2967.