Double-Stimuli-Responsive (Temperature and pH) Aqueous Biphasic Systems Comprising Ionic Liquids

Aqueous biphasic systems (ABS) can integrate multiple unit operations and operate under continuous mode, contributing to the development of sustainable separation processes. Encouraged by designer solvent features ionic liquids (ILs), we herein propose their use as components double-stimuli-responsive (temperature- pH-driven) ABS. Resorting choline-alkanoate-based ILs pH-responsive poly(propylene glycol) (PPG 400) thermo-responsive component, ABS ternary phase diagrams are determined at various temperature (25–45 °C) pH (3–7) conditions. While liquid–liquid diagram response obeys a lower critical solution temperature-like behavior, correlates with pKa IL anion parent acid. The simultaneous responsiveness is then shown, whose results inspire customizable techniques proved (one-step) two dyes. By proper customization chemical structure stimuli applied, may be designed improve performance sustainability