(544h) Separation of Hydrofluorocarbon Mixtures Using Ionic Liquids

Hydrofluorocarbons (HFCs) are organic compounds that are commonly used as refrigerants. HFCs were introduced as a replacement to chlorofluorocarbons (CFCs) in response to the Montreal Protocol due to their low Ozone Depletion Potential (ODP). Although HFCs have low ODP, many have a high Global Warming Potential (GWP) and are now being phased out as a result of the Kigali agreement and replaced with hydrofluoroolefins (HFOs). The phasing out of HFCs and HFC mixtures alone is leading to thousands of tons of refrigerants being unusable with the only options for disposal being to vent or incinerate them. It is important that new techniques are developed to sustainably separate and recycle HFC mixtures so they can be disposed of properly or repurposed in new, more environmentally friendly refrigerants such as HFO mixtures.

Project EARTH (Environmentally Applied Research Toward Hydrofluorocarbons) is a collaborative project between multiple universities and industry companies that is focused on developing efficient and selective separation processes and recycling methods for HFC mixtures. The separation of HFC mixtures is difficult due to the fact that many of the mixtures are azeotropic or near azeotropic. For this reason, Project EARTH is looking into multiple approaches to this challenge, one of which being the use of ionic liquids (ILs). We believe that IL’s properties (no measurable vapor pressure, dissolution of many organic and inorganic compounds, variable solubility of gases and liquids, and high thermal, chemical, and electrochemical stability) make them uniquely suited to creating selective separation processes for various HFC mixtures.

This presentation will cover results on the use of various ILs for the separation of refrigerant mixture R-410a which is a 50/50 mixture by weight of R-125 (CHF₂CH₃) and R-32 (CH₂F₂).