Recycling hydrofl uoric acid (HF) is a signifi cant issue within the fi eld of organofl uoride chemistry. A key obstacle in

this endeavor lies in the separation of azeotropic mixtures containing HF, such as the azeotropic mixture of HF and

1,1,1,3,3-pentafl uoropropane (HFC-245fa), which exhibit similar boiling points. This study investigates the application of

extractant distillation (ED) with ionic liquids (ILs) to achieve the separation of HF/HFC-245fa at the molecular scale, cell

dimension, and systematic level (including the optimization and analysis of ED). COSMO-RS was employed to identify

the suitable IL, with [Tf 2 N]-based ILs emerging as the most optimal extractants. Four representative [Tf 2 N]-based ILs

were chosen based on their physical properties and thermodynamic behavior, and were applied in a continuous ED process

simulation for the separation of HF/HFC-245fa using Aspen Plus, resulting in the production of 99.5 mol% HFC-245fa

and 99.5 mol% HF. The determination of the optimal operational parameters was carried out through sequential quadratic

programming, considering the purity requirements. An assessment of energy consumption analysis indicated that [C 1 Py]

[Tf 2 N] stands out as the most suitable IL for separation of HF/HFC-245fa, with heat and cooling duties of 467.82 kW and

304.80 kW, respectively. Economic analysis for the process with [C 1 Py][Tf 2 N] indicated that the annual operating costs and

equipment costs are $ 5.58 × 10 4 and $ 3.75 × 10 6 , respectively, of which the costs of IL are 93%, the total annual cost was

comparable to that of the pressure-swing distillation process, suggesting that this ED process utilizing ILs for separating

azeotropes is economically viable in terms of industrial application.