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The research on porous materials for the selective capture of fluorinated gases (F-gases) is key to reduce their emissions. Here, the adsorption of difluoromethane (R-32), pentafluoroethane (R-125), and 1,1,1,2-tetrafluoroethane (R-134a) is studied in four metal-organic frameworks (MOFs: Cu-benzene-1,3,5-tricarboxylate, zeolitic imidazolate framework-8, MOF-177, and MIL-53(Al)) and in one zeolite (ZSM-5) with the aim to develop technologies for the efficient capture and separation of high global warming potential blends containing these gases. Single-component sorption equilibria of the pure gases are measured at three temperatures (283.15, 303.15, and 323.15 K) by gravimetry and correlated using the Tóth and Virial adsorption models, and selectivities toward R-410A and R-407F are determined by ideal adsorption solution theory. While at lower pressures, R-125 and R-134a are preferentially adsorbed in all materials, at higher pressures there is no selectivity, or it is shifted toward the adsorption R-32. Furthermore, at high pressures, MOF-177 shows the highest adsorption capacity for the three F-gases. The results presented here show that the utilization of MOFs, as tailored made materials, is promising for the development of new approaches for the selective capture of F-gases and for the separation of blends of these gases, which are used in commercial refrigeration.

In recent years, the fight against climate change and the mitigation of the impact of fluorinated gases (F-gases) on the atmosphere is a global concern. Development of technologies that help to efficiently separate and recycle hydrofluorocarbons (HFCs) at the end of the refrigeration and air conditioning equipment life is a priority. The technological development is important to stimulate the F-gas capture, specifically difluoromethane (R-32) and 1,1,1,2-tetrafluoroethane (R-134a), due to their high global warming potential. In this work, the COSMO-RS method is used to analyze the solute-solvent interactions and to determine Henry's constants of R-32 and R-134a in more than 600 ionic liquids. The three most performant ionic liquids were selected on the basis of COSMO-RS calculations, and F-gas absorption equilibrium isotherms were measured using gravimetric and volumetric methods. Experimental results are in good agreement with COSMO-RS predictions, with the ionic liquid tributyl(ethyl)phosphonium diethyl phosphate, [P2444][C2C2PO4], being the salt presenting the highest absorption capacities in molar and mass units compared to salts previously tested. The other two ionic liquids selected, trihexyltetradecylphosphonium glycinate, [P66614][C2NO2], and trihexyl(tetradecyl)phosphonium 2-cyano-pyrrole, [P66614][CNPyr], may be competitive as far as their absorption capacities are concerned. Future works will be guided on evaluating the performance of these ionic liquids at an industrial scale by means of process simulations, in order to elucidate the role in process efficiency of other relevant absorbent properties such as viscosity, molar weight, or specific heat, This work was also supported by Associate Laboratory for Green Chemistry–LAQV, financed by national funds from FCT/MCTES (UID/QUI/50006/2020), the contracts of Individual Call to Scientific Employment Stimulus 2020.00835.CEECIND (J.M.M.A.)/2021.01432.CEECIND (A.B.P.) and by FCT/MCTES (Portugal) through the project PTDC/EQU-EQU/29737/2017. The authors thank Solvay for providing the ionic liquid tri(butyl) ethylphosphonium diethylphosphate. M.C.G. and J.A. thank IDEX-LYON for financial support (Programme Investissement d’Avenir ANR-16-IDEX-0005)

funding of the KET4F-Gas project, SOE2/P1/P0823, co -funded by the Interreg Sudoe Programme through the European Regional Development Fund (ERDF). FCT/MCTES for financial support through IF/00190/2014 , IF/00210/2014 financial support through the Norma TransitOria DL 57/2016 Program Contract (FCT/MCTES). FCT/MCTES (UID/QUI/50006/2019). The increasing awareness of the environmental impact of fluorinated gases (F-gases) used in refrigeration is instigating the development of technologies to recover and recycle them. With this goal in mind, single-component absorption equilibrium isotherms at 303.15 K of F-gases in different ionic liquids (ILs) were determined using a gravimetric method. The selected F-gases are the most used in domestic refrigeration (R-32: difluoromethane, R-125: pentafluoroethane, and R-134a: 1,1,1,2-tetrafluoroethane). The results show that ILs containing a fluorinated alkyl side chain with four carbon atoms, that is, fluorinated ILs (FILs), have higher gas absorption capacity than conventional fluoro-containing ILs. All studied ILs showed ideal selectivity toward R-134a. Conventional fluoro-containing ILs showed better selectivities for the separation of the binary mixtures R-134a/R-125 and R-32/R-125, and FILs showed better selectivities for the R-134a/R-32 mixture. These results provide fundamental knowledge of the behavior of these new alternative solvents and key information for their application in the separation of F-gas mixtures of commercial refrigerants. authorsversion published

PTDC/EQU-EQU/29737/2017; FCT/MCTES (UIDB/50006/2020). The environmental impact resulting from the release of fluorinated gases (F-gases), commonly used in refrigeration, is prompting the development of technologies to recover and recycle them. Fluorinated ionic liquids (FILs) have been investigated as promising candidates for the absorption and selective separation of F-gases. In this work, we prepared deep eutectic solvents (DESs) composed of FILs and perfluorinated acids to explore the excellent gas solubilization properties of FILs with high melting points in a wider liquid range. A screening of DESs prepared from five different FILs was performed for the solubilization of 1,1,1,2-tetrafluoroethane (R-134a) at 303.15 K, using a stainless steel volumetric system. [N4444][C4F9SO3]/C4F9CO2H and [C2C1Im][C8F17SO3]/C4F9CO2H were selected as the systems with the best absorption capacities and were studied in three different molar ratios of FIL/perfluorinated acid. Then, the absorption of difluoromethane (R-32), pentafluoroethane (R-125), and R-134a were determined at 303.15, 313.15, and 323.15 K. All studied DESs have high selectivity for the separation of R-134a from their mixtures with the other two F-gases. The results presented here provide knowledge of the behavior of these new alternative solvents for the separation of F-gases from commercial refrigerants, at three different temperatures, and in a wide range of operating pressures. authorsversion published

Funding of the KET4F-Gas project, SOE2/P1/P0823, co-funded by the Interreg Sudoe Program through the European Regional Development Fund (ERDF). A.B. Pereiro and J.M.M. Araújo acknowledge FCT/MCTES for financial support through IF/00190/2014 contract and IF/00210/2014 contract, respectively. Rui Ribeiro acknowledges financial support through the Norma Transitória DL 57/2016 Program Contract (FCT/MCTES). This work was also supported by the Associate Laboratory for Green Chemistry ? LAQV, which is financed by national funds from FCT/MCTES (UID/QUI/50006/2019). Background: The increasing awareness of the release of fluorinated gases (F-gases) into the atmosphere is instigating the development of techniques to capture them from refrigerants. In this work, the adsorption of difluoromethane (R-32), pentafluoroethane (R-125), and 1,1,1,2-tetrafluoroethane (R-134a) on four different activated carbons (ACs) is studied. Additionally, the selectivity of the ACs for the components of commercial refrigerants, R-410A and R-407F, is evaluated. Results: The estimation of the density of the adsorbed phase as a function of temperature allows the experimental fractional loading of each F-gas on any of the ACs to be correlated as a temperature-independent function of its reduced pressure, which is described by Tóth or dual-site Langmuir equations or as an exponential function of the adsorption potential under the framework of the Adsorption Potential theory (APT). It is shown that the APT can be generalized with excellent accuracy to the systems studied if an adsorbate-dependent affinity coefficient is used as a shifting factor to bring the characteristic curves of all F-gases into a single one for each AC. R-32 is the F-gas most adsorbed by all adsorbents, followed by R-134a, and by R-125. All ACs are selective for R-125 in R-410A commercial refrigerants, especially at lower pressures. Additionally, all ACs are selective for R-125 and R-134a over R-32 in R407-F commercial refrigerant. Conclusion: The utilization of ACs for adsorption of the three most used F-gases is promising. By selecting ACs with different porous characteristics, it is possible to evaluate their influence on the selectivity for the components of different commercial refrigerants. authorsversion published

IF/00190/2014; IF/00210/2014; PTDC/EQU-EQU/29737/2017; PTDC/QEQ-FTT/3289/2014; IF/00210/2014/CP1244/CT0003; UID/QUI/50006/2019; POCI-01-0145-FEDER-007265; University of Pamplona, Internal Project 2-2017. The aim of this work is to evaluate the separation of hydrocarbons (hexane and heptane) from their azeotropic mixtures with ethanol using protic ionic liquid (PIL) as extraction solvents. With this goal in mind, PILs were synthesized and their thermal and physical characterization were carried out. Experimental determination of the phase equilibrium for the ternary systems hydrocarbons + ethanol + PIL at 298.15 K and 101.2 kPa were also carried out in order to evaluate the feasibility of this application. The solute distribution ratio and the selectivity were also determined to compare the solvent capacity of these PILs. The NRTL equation was used to correlate the experimental data. Furthermore, this paper provides a comparison of the solvent capacity of these PILs with different extraction solvents (ionic liquids (ILs), ILs mixtures and deep eutectic solvents) available in the literature. Then, a critical review for the separation of these azeotropic mixtures was carried out using the extraction processes data obtained through the simulation using a conventional software. preprint published