Absorption of Fluorinated Greenhouse Gases in Deep\nEutectic Solvents

Abstract

The\nenvironmental impact resulting from the release of fluorinated\ngases (F-gases), commonly used in refrigeration, is prompting the\ndevelopment of technologies to recover and recycle them. Fluorinated\nionic liquids (FILs) have been investigated as promising candidates\nfor the absorption and selective separation of F-gases. In this work,\nwe prepared deep eutectic solvents (DESs) composed of FILs and perfluorinated\nacids to explore the excellent gas solubilization properties of FILs\nwith high melting points in a wider liquid range. A screening of DESs\nprepared from five different FILs was performed for the solubilization\nof 1,1,1,2-tetrafluoroethane (R-134a) at 303.15 K, using a stainless\nsteel volumetric system. [N₄₄₄₄]­[C₄F₉SO₃]/C₄F₉CO₂H and [C₂C₁Im]­[C₈F₁₇SO₃]/C₄F₉CO₂H were selected as the\nsystems with the best absorption capacities and were studied in three\ndifferent molar ratios of FIL/perfluorinated acid. Then, the absorption\nof difluoromethane (R-32), pentafluoroethane (R-125), and R-134a were\ndetermined at 303.15, 313.15, and 323.15 K. All studied DESs have\nhigh selectivity for the separation of R-134a from their mixtures\nwith the other two F-gases. The results presented here provide knowledge\nof the behavior of these new alternative solvents for the separation\nof F-gases from commercial refrigerants, at three different temperatures,\nand in a wide range of operating pressures.