Sustainable separation of azeotrope trifluoroethanol and water by intensified ionic liquid-based extractive distillation

2,2,2-Trifluoroethanol (TFE) is widely used as an organic synthetic solvent, fluorine-containing intermediate, raw material for biomedicine owing to its strong polarity and unique fluorinated structure. Since TFE and water can generate an azeotrope, it is a significant challenge to separate TFE and water. In this paper, extractive distillation was adopted to separate TFE and water using an ionic liquid [EMIM][Cl] as the extractant. The σ-profile analysis revealed that [EMIM][Cl] possessed strong hydrogen-bond acceptor capability, with superior water solubility and selectivity compared to the other ionic liquids. The vapor-liquid equilibrium results confirmed that 20 mol% [EMIM][Cl] can effectively eliminate the azeotropic point. Herein, an ionic-liquid-based vapor side stream extractive distillation (VSED) process was developed and optimized using Multi-Objective Particle Swarm Optimization (MOPSO) to simultaneously minimize total annualized cost (TAC) and CO 2 emissions. The optimization results demonstrated that VSED reduces TAC by 18.7% and CO 2 emissions by 7.2% compared to conventional ionic liquid-based extractive distillation (CED). Furthermore, a synergistic feedforward-feedback control strategy was designed, successfully maintaining stable operation under disturbances of ±20% feed flow rate and ±5% feed composition with vapor side-stream (VSS) flow response accelerated by 60%, and tray 39 temperature recovery time reduced by 50%, confirming the process's industrial feasibility.