The separation of refrigerant mixtures is a critical challenge in refrigerant recovery and recycling, particularly as regulations on high-global-warming-potential (GWP) refrigerants become more stringent. Ionic liquids (ILs) have emerged as promising candidates for refrigerant separation due to their negligible vapor pressures, adjustable solvation properties, and high thermal stability. However, selecting an optimal IL for a given refrigerant mixture remains a challenge due to the vast number of IL structures. In this study, we propose a novel screening method utilizing gas chromatography (GC) to evaluate ILs for refrigerant separation. By coating a capillary column with a thin film of IL and injecting various refrigerants, we can analyze retention times to assess interactions between the IL and each refrigerant. Shorter retention times indicate weaker interactions, whereas longer retention times suggest stronger interactions and therefore successful separation, enabling an assessment of IL selectivity. This approach offers a reproducible method for identifying ILs best suited for selective refrigerant separations. The results of this study will inform the development of more efficient separation processes, contributing to sustainable refrigerant recycle and reuse strategies.
