Rubén SANTIAGO1, Julio E. SOSA3, Joao M. M. ARAUJO3, Margarida COSTA GOMES4, Ana B. PEREIRO3, José PALOMAR2
1Universidad Politécnica de Madrid, Madrid, Spain
2Universidad Autónoma de Madrid, Madrid, Spain
3NOVA University Lisbon, Lisbon, Portugal
4Ecole Normale Superieure de Lyon & CNRS, Lyon, France
The mitigation of fluorinated gases (F-gases) in the atmosphere is a global concern since it contributes to the fight against climate change. It is necessary to develop efficient and effective technologies to eliminate these contaminant gases. Ionic liquids (ILs) have been proposed as F-gases absorbents due to their excellent solvent properties such as low vapor pressure, high thermal and chemical stability, and high solvent capacity, among others. The use of COSMO/Aspen methodology allows to evaluate the behavior of previously proposed fluorinated ionic liquids for R-134a and R-32 absorption at process scale 1. It was found a kinetic control in the most viscous ILs, enhancing the little differences between the evaluated ILs when only thermodynamic solubility is considered. Complete process performance was also carried out revealing 1-ethyl-3-methylimidazolium triflate as the best candidate with competitive operating costs when compared with other typical gases absorption processes. Then, COSMO-RS method was also used for the search of new ILs that may present favorable properties for F-gases absorption 2. COSMO-RS calculations permit to select three ILs presenting favorable properties for F-gases absorption when compared with ILs previously studied. Then, these ILs could be synthetized and characterized. Specifically, tributyl(ethyl)phosphonium diethyl phosphate is concluded to be the best candidate for both R-134 and R-32 absorption in terms of molar and mass solubility. Future research will be conducted regarding the evaluation of these ILs at process scale, analyzing viscosity, molar weight, and other parameters of relevance.
(1) Sosa, J. E.; Santiago, R.; Hospital-Benito, D.; Gomes, M. C.; Araujo, J. M. M.; Pereiro, A. B.; Palomar, J. Process Evaluation of Fluorinated Ionic Liquids as F-Gas Absorbents. Environmental Science & Technology 2020, 54 (19), 12784.
(2) Sosa, J. E.; Santiago, R.; Redondo, A. E.; Avila, J.; Lepre, L. F.; Gomes, M. C.; Araújo, J. M. M.; Palomar, J.; Pereiro, A. B. Design of Ionic Liquids for Fluorinated Gas Absorption: COSMO-RS Selection and Solubility Experiments. Environmental Science & Technology 2022, 56 (9), 5898.