A Single-Stage, Continuous High-Efficiency Extraction Device (HEED) for Flow Synthesis

A prototype continuous-flow high-efficiency extraction device (HEED) is reported. The device is compatible with a wide-range of systems and can be used without modification for extractions into higher or lower density solvents. The design balances high-extraction efficiency with low (millisecond) residence time to provide products of high purity over >20 h of continuous operation, corresponding to gram-scale extractions. Device performance was characterized over time for three extractions, each involving a different solvent system and recovery into different phases (i.e., organic and aqueous). In all cases the HEED was capable of matching batch extraction efficiency over an indefinite period following an initial “loading and stabilization” phase.