Smart Dual-Responsive Ionic Liquid as Transformable and Recyclable Media for Extracting and Separating Phytochemicals from Wild <i>Rumex acetosa</i> L.

In this work, a dual-responsive ionic liquid (DR-IL), namely, [C4mim][FeCl4] was developed for simultaneously extracting and separating hydrophilic phytochemicals, including epicatechin (EC), dihydroquercetin (DQ), ferulic acid (FA), and hydrophobic phytochemicals, such as emodin (ED), chrysophanol (CP), and physcion (PC), from roots of wild Rumex acetosa L. The [C4mim][FeCl4] demonstrates considerable potential for extracting and separating target phytochemicals through temperature adjustment and accelerated phase separation facilitated by a neodymium magnet. Meanwhile, a high recovery yield is obtained by adding a magnetic field. The overall extraction yield of target phytochemicals achieved by [C4mim][FeCl4] reaches 16.12 mg/g under the optimal extraction conditions, representing a 1.53–2.39-fold increase compared to conventional solvents. Furthermore, the molecular simulation and FT-IR analysis reveal that the synergistic effect of van der Waals forces and hydrogen bonds significantly contributed to the higher extraction yields of target phytochemicals.