Liquid–Liquid Equilibrium Data of Water + Butanol/Acetone + 2‑Hydroxyethylammonium-Based Protic Ionic Liquids

Environmentally friendly alternatives have been recently developed focusing on the search for less aggressive, more innovative, and sustainable chemical processes and products. Regarding this, two green optionsbiobutanol, as the next generation of renewable fuel better than ethanol, and protic ionic liquids (PILs), a class of ionic liquids (ILs), as green design solvents with easier recovery and purification processesare attracting widespread interest. Looking forward to a more economically feasible and sustainable process, this study mainly investigated biorefinery byproduct-based PILs (acetate and butyrate anions) for n-butanol recovery. For that, liquid–liquid equilibrium (LLE) data of ternary systems composed of water + butanol/acetone + PIL using the cloud-point titration method were determined at different temperatures (293.15 and 323.15 K), and the data were fitted to the nonrandom-two-liquid (NRTL) model to obtain the model binary interaction parameters, yielding RMSD below 1.91%. The PILs studied were 2-hydroxyethylammonium acetate (HEAA), bis­(2-hydroxyethyl)­ammonium acetate (BHEAA), tris­(2-hydroxyethyl)­ammonium acetate (THEAA), 2-hydroxyethylammonium butyrate (HEAB), bis­(2-hydroxyethyl)­ammonium butyrate (BHEAB), and tris­(2-hydroxyethyl)­ammonium butyrate (THEAB).