Slug Flow of Ionic Liquids in Capillary Microcontactors: Fluid Dynamic Intensification for Solvent Extraction

Abstract

Abstract For merging two facets of process intensification, namely, slug flow in microcapillaries and ionic liquid extraction, the fluid mechanic stability of organic‐ionic liquid slug flow is mapped for [EMIM] [Alkyl‐SO 4 ] and [Alkyl‐MIM] [Ntf2] in 0.5–1.0 mm ID plastic capillaries. The choice of the ionic liquid solvent is restricted by physical properties. The internal circulation within ionic liquid slugs is found to be slower by a factor of 2–10 compared to aqueous slugs, but is accelerated by optimizing velocity, temperature, and wall material. Extraction of acetic acid from n ‐heptane with EMIM ethyl sulfate is proposed as a system to verify the contribution of internal circulation to mass transfer. In the long run, this research affirms the fluid dynamic feasibility of microcapillary slug‐flow extraction with ionic liquids.