Vapor–Liquid\nEquilibrium Experiment and Thermodynamic\nCorrelation of Methyl Ethyl Carbonate + Ethanol + 1‑Hexyl-3-methylimidazolium\nBis(trifluoromethylsulfonyl)imide and 1‑Ethyl-3-methylimidazolium\nBis(trifluoromethylsulfonyl)imide at 101.3 kPa

Methyl\nethyl carbonate (EMC) is an essential solvent\nin the production\nprocess of lithium batteries, which is in high market demand. However,\nit is costly and lacks purity. Preparing EMC with ethanol and dimethyl\ncarbonate is environmentally friendly and efficient. Still, an azeotropic\nmixture of EMC and ethanol is formed during preparation, making it\nimpossible for conventional distillation to separate these two substances.\nTherefore, this work adopts extraction distillation to separate the\nEMC–ethanol azeotropic system, selecting two ionic liquids\n(ILs), 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide\n([HMIM][NTf<sub>2</sub>]) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide\n([EMIM][NTf<sub>2</sub>]), as entrainers. The vapor–liquid\nequilibrium (VLE) experiment of the EMC (1) + ethanol (2) + ILs (3)\nternary system was conducted under atmospheric pressure (101.3 kPa).\nThe experimental results indicate that both ILs can eliminate azeotropic\npoints and the separation ability of [HMIM][NTf<sub>2</sub>] is slightly\nstronger than that of [EMIM][NTf<sub>2</sub>]. The NRTL model was\nused to fit the experimental data, with ARDs of 4.17 and 4.40%, respectively,\nproving that the model is suitable for the system.