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In the search for alternatives to chlorine-containing gases, tetrafluoroethane, CF3CH2F (R134a), a widely used refrigerant gas, has been recognized as a promising substitute for dichlorodifluoromethane, CCl2F2 (R12). When R12 is replaced by R134a, the global warming potential drops from 8100 to 1430, the ozone depletion potential changes from 1 to 0, and the atmospheric lifetime decreases from 100 to 14 years. Electron interactions in the gas phase play a fundamental role in the atmospheric sciences. Here, we present a detailed study on electron-driven fragmentation pathways of CF3CH2F, in which we have investigated processes induced by both electron ionization and electron attachment. The measurements allow us to report the ion efficiency curves for ion formation in the energy range of 0 up to 25 eV. For positive ion formation, R134a dissociates into a wide assortment of ions, in which CF3+ is observed as the most abundant out of seven ions with a relative intensity above 2%. The results are supported by quantum chemical calculations based on bound state techniques, electron-impact ionization models, and electron-molecule scattering simulations, showing a good agreement. Moreover, the experimental first ionization potential was found at 13.10 ± 0.17 eV and the second at around 14.25 eV. For negative ion formation, C2F3– was detected as the only anion formed, above 8.3 eV. This study demonstrates the role of electrons in the dissociation of R134a, which is relevant for an improvement of the refrigeration processes as well as in atmospheric chemistry and plasma sciences.
João Pereira-Da-Silva; Rodrigo Rodrigues; João Ramos; Carlos Brígido; Alexandru Botnari; Miguel Silvestre; João Ameixa; Mónica Mendes; Fábio Zappa; Stephen J. Mullock; João M. M. Araújo; Márcio T. Do N. Varella; Lucas M. Cornetta; Filipe Ferreira da Silva. Electron Driven Reactions in Tetrafluoroethane: Positive and Negative Ion Formation. Journal of the American Society for Mass Spectrometry 2021, 32, 1459 -1468.
AMA StyleJoão Pereira-Da-Silva, Rodrigo Rodrigues, João Ramos, Carlos Brígido, Alexandru Botnari, Miguel Silvestre, João Ameixa, Mónica Mendes, Fábio Zappa, Stephen J. Mullock, João M. M. Araújo, Márcio T. Do N. Varella, Lucas M. Cornetta, Filipe Ferreira da Silva. Electron Driven Reactions in Tetrafluoroethane: Positive and Negative Ion Formation. Journal of the American Society for Mass Spectrometry. 2021; 32 (6):1459-1468.
Chicago/Turabian StyleJoão Pereira-Da-Silva; Rodrigo Rodrigues; João Ramos; Carlos Brígido; Alexandru Botnari; Miguel Silvestre; João Ameixa; Mónica Mendes; Fábio Zappa; Stephen J. Mullock; João M. M. Araújo; Márcio T. Do N. Varella; Lucas M. Cornetta; Filipe Ferreira da Silva. 2021. "Electron Driven Reactions in Tetrafluoroethane: Positive and Negative Ion Formation." Journal of the American Society for Mass Spectrometry 32, no. 6: 1459-1468.
Fluorinated greenhouse gases (F-gases) are used for various applications, such as in refrigeration and air conditioning, as substitutes of the ozone-depleting substances. Their utilization has increased drastically over the last few decades, with serious consequences for global warming. The Kigali Amendment to the Montreal Protocol and several national and international legislations, such as the 2014 EU F-gas Regulation, aim to control the utilization and emissions of these gases. In the EU, the phase-down of hydrofluorocarbons (HFCs) is underway, with successive reductions in quotas up to 2050. Under this scenario, efficient strategies for managing the produced and already existing F-gases are of vital importance to guarantee that their effect on the environment is mitigated. Up to now, most of the F-gases recovered from end-of-life equipment or when retrofitting systems are either released into the atmosphere or destroyed. However, in order to put forward a cost-efficient adaptation to the F-gas phase-down, increasing separation and recycling efforts must be made. This critical review aims at providing a revision of the current F-gas management problems and strategies and providing an overview on the innovative strategies that can be applied to contribute to build a sustainable market under circular economy principles.
Paulo Castro; João Aráujo; Graça Martinho; Ana Pereiro. Waste Management Strategies to Mitigate the Effects of Fluorinated Greenhouse Gases on Climate Change. Applied Sciences 2021, 11, 4367 .
AMA StylePaulo Castro, João Aráujo, Graça Martinho, Ana Pereiro. Waste Management Strategies to Mitigate the Effects of Fluorinated Greenhouse Gases on Climate Change. Applied Sciences. 2021; 11 (10):4367.
Chicago/Turabian StylePaulo Castro; João Aráujo; Graça Martinho; Ana Pereiro. 2021. "Waste Management Strategies to Mitigate the Effects of Fluorinated Greenhouse Gases on Climate Change." Applied Sciences 11, no. 10: 4367.
Proteins are bioactive compounds with high potential to be applied in the biopharmaceutical industry, food science and as biocatalysts. However, protein stability is very difficult to maintain outside of the native environment, which hinders their applications. Fluorinated ionic liquids (FILs) are a promising family of surface-active ionic liquids (SAILs) that have an amphiphilic behavior and the ability to self-aggregate in aqueous solutions by the formation of colloidal systems. In this work, the protein lysozyme was selected to infer on the influence of FILs in its stability and activity. Then, the cytotoxicity of FILs was determined to evaluate their biocompatibility, concluding that the selected compounds have neglected cytotoxicity. Therefore, UV–visible spectroscopy was used to infer the FIL-lysozyme interactions, concluding that the predominant interaction is the encapsulation of the lysozyme by FILs. The encapsulation efficiency was also tested, which highly depends on the concentration and anion of FIL. Finally, the bioactivity and thermal stability of lysozyme were evaluated, and the encapsulated lysozyme keeps its activity and thermal stability, concluding that FILs can be a potential stabilizer to be used in protein-based delivery systems.
Margarida Ferreira; Nicole Vieira; João Araújo; Ana Pereiro. Unveiling the Influence of Non-Toxic Fluorinated Ionic Liquids Aqueous Solutions in the Encapsulation and Stability of Lysozyme. Sustainable Chemistry 2021, 2, 149 -166.
AMA StyleMargarida Ferreira, Nicole Vieira, João Araújo, Ana Pereiro. Unveiling the Influence of Non-Toxic Fluorinated Ionic Liquids Aqueous Solutions in the Encapsulation and Stability of Lysozyme. Sustainable Chemistry. 2021; 2 (1):149-166.
Chicago/Turabian StyleMargarida Ferreira; Nicole Vieira; João Araújo; Ana Pereiro. 2021. "Unveiling the Influence of Non-Toxic Fluorinated Ionic Liquids Aqueous Solutions in the Encapsulation and Stability of Lysozyme." Sustainable Chemistry 2, no. 1: 149-166.
The task-specific design of ionic liquids (ILs) has emerged in several industrial and pharmaceutical applications. The family of ILs with fluorine tags equal to or longer than four carbon atoms, the fluorinated ionic liquids (FILs), combine the best properties of ILs with the ones of perfluorinated compounds, and are being designed for several specific purposes. In the pharmaceutical field, there is an urgency to search for novel antibacterial agents to overcome problems associated to antimicrobial resistances. Then, the main purpose of this work is to evaluate the environmental impact and the ability of FILs to be used as antibacterial agents against Pseudomonas stutzeri bacteria. Beyond its rare pathogenicity, these bacteria are also used as a bioremediation agent to treat several contamination sites. Then, it is important to determine which FILs have antibacterial properties, and which do not impact the bacterial growth. The biocompatibility of FILs was also evaluated through their hemolytic activity and represent a step forward the application of FILs in pharmaceutical applications. The results proved that high concentrations of FILs can have a reduced ecotoxicity and a high biocompatibility. [C8C1Im][CF3SO3] was identified as the most promising compound to be used as an antibacterial agent since it prevents the growth of bacteria at concentrations compatible with the red blood cells’ viability.
Nicole Vieira; Ana Oliveira; João Araújo; Maria Gaspar; Ana Pereiro. Ecotoxicity and Hemolytic Activity of Fluorinated Ionic Liquids. Sustainable Chemistry 2021, 2, 115 -126.
AMA StyleNicole Vieira, Ana Oliveira, João Araújo, Maria Gaspar, Ana Pereiro. Ecotoxicity and Hemolytic Activity of Fluorinated Ionic Liquids. Sustainable Chemistry. 2021; 2 (1):115-126.
Chicago/Turabian StyleNicole Vieira; Ana Oliveira; João Araújo; Maria Gaspar; Ana Pereiro. 2021. "Ecotoxicity and Hemolytic Activity of Fluorinated Ionic Liquids." Sustainable Chemistry 2, no. 1: 115-126.
In this work, polymeric membranes functionalized with ionic liquids (ILs) and exfoliated graphene nanoplatelets (xGnP) were developed and characterized. These membranes based on graphene ionanofluids (IoNFs) are promising materials for gas separation. The stability of the selected IoNFs in the polymer membranes was determined by thermogravimetric analysis (TGA). The morphology of membranes was characterized using scanning electron microscope (SEM) and interferometric optical profilometry (WLOP). SEM results evidence that upon the small addition of xGnP into the IL-dominated environment, the interaction between IL and xGnP facilitates the migration of xGnP to the surface, while suppressing the interaction between IL and Pebax®1657. Fourier transform infrared spectroscopy (FTIR) was also used to determine the polymer–IoNF interactions and the distribution of the IL in the polymer matrix. Finally, the thermodynamic properties and phase transitions (polymer–IoNF) of these functionalized membranes were studied using differential scanning calorimetry (DSC). This analysis showed a gradual decrease in the melting point of the polyamide (PA6) blocks with a decrease in the corresponding melting enthalpy and a complete disappearance of the crystallinity of the polyether (PEO) phase with increasing IL content. This evidences the high compatibility and good mixing of the polymer and the IoNF.
Carolina Hermida-Merino; Fernando Pardo; Gabriel Zarca; João Araújo; Ane Urtiaga; Manuel Piñeiro; Ana Pereiro. Integration of Stable Ionic Liquid-Based Nanofluids into Polymer Membranes. Part I: Membrane Synthesis and Characterization. Nanomaterials 2021, 11, 607 .
AMA StyleCarolina Hermida-Merino, Fernando Pardo, Gabriel Zarca, João Araújo, Ane Urtiaga, Manuel Piñeiro, Ana Pereiro. Integration of Stable Ionic Liquid-Based Nanofluids into Polymer Membranes. Part I: Membrane Synthesis and Characterization. Nanomaterials. 2021; 11 (3):607.
Chicago/Turabian StyleCarolina Hermida-Merino; Fernando Pardo; Gabriel Zarca; João Araújo; Ane Urtiaga; Manuel Piñeiro; Ana Pereiro. 2021. "Integration of Stable Ionic Liquid-Based Nanofluids into Polymer Membranes. Part I: Membrane Synthesis and Characterization." Nanomaterials 11, no. 3: 607.
Membrane technology can play a very influential role in the separation of the constituents of HFC refrigerant gas mixtures, which usually exhibit azeotropic or near-azeotropic behavior, with the goal of promoting the reuse of value-added compounds in the manufacture of new low-global warming potential (GWP) refrigerant mixtures that abide by the current F-gases regulations. In this context, the selective recovery of difluorometane (R32, GWP = 677) from the commercial blend R410A (GWP = 1924), an equimass mixture of R32 and pentafluoroethane (R125, GWP = 3170), is sought. To that end, this work explores for the first time the separation performance of novel mixed-matrix membranes (MMMs) functionalized with ioNanofluids (IoNFs) consisting in a stable suspension of exfoliated graphene nanoplatelets (xGnP) into a fluorinated ionic liquid (FIL), 1-ethyl-3-methylpyridinium perfluorobutanesulfonate ([C2C1py][C4F9SO3]). The results show that the presence of IoNF in the MMMs significantly enhances gas permeation, yet at the expense of slightly decreasing the selectivity of the base polymer. The best results were obtained with the MMM containing 40 wt% IoNF, which led to an improved permeability of the gas of interest (PR32 = 496 barrer) with respect to that of the neat polymer (PR32 = 279 barrer) with a mixed-gas separation factor of 3.0 at the highest feed R410A pressure tested. Overall, the newly fabricated IoNF-MMMs allowed the separation of the near-azeotropic R410A mixture to recover the low-GWP R32 gas, which is of great interest for the circular economy of the refrigeration sector.
Fernando Pardo; Sergio Gutiérrez-Hernández; Carolina Hermida-Merino; João Araújo; Manuel Piñeiro; Ana Pereiro; Gabriel Zarca; Ane Urtiaga. Integration of Stable Ionic Liquid-Based Nanofluids into Polymer Membranes. Part II: Gas Separation Properties toward Fluorinated Greenhouse Gases. Nanomaterials 2021, 11, 582 .
AMA StyleFernando Pardo, Sergio Gutiérrez-Hernández, Carolina Hermida-Merino, João Araújo, Manuel Piñeiro, Ana Pereiro, Gabriel Zarca, Ane Urtiaga. Integration of Stable Ionic Liquid-Based Nanofluids into Polymer Membranes. Part II: Gas Separation Properties toward Fluorinated Greenhouse Gases. Nanomaterials. 2021; 11 (3):582.
Chicago/Turabian StyleFernando Pardo; Sergio Gutiérrez-Hernández; Carolina Hermida-Merino; João Araújo; Manuel Piñeiro; Ana Pereiro; Gabriel Zarca; Ane Urtiaga. 2021. "Integration of Stable Ionic Liquid-Based Nanofluids into Polymer Membranes. Part II: Gas Separation Properties toward Fluorinated Greenhouse Gases." Nanomaterials 11, no. 3: 582.
Ismail I. I. Alkhatib; Margarida L. Ferreira; Carlos G. Alba; Daniel Bahamon; Fèlix Llovell; Ana B. Pereiro; João M. M. Araújo; Mohammad R.M. Abu-Zahra; Lourdes F. Vega. Screening of Ionic Liquids and Deep Eutectic Solvents for Physical CO2 Absorption by Soft-SAFT Using Key Performance Indicators. Journal of Chemical & Engineering Data 2020, 65, 5844 -5861.
AMA StyleIsmail I. I. Alkhatib, Margarida L. Ferreira, Carlos G. Alba, Daniel Bahamon, Fèlix Llovell, Ana B. Pereiro, João M. M. Araújo, Mohammad R.M. Abu-Zahra, Lourdes F. Vega. Screening of Ionic Liquids and Deep Eutectic Solvents for Physical CO2 Absorption by Soft-SAFT Using Key Performance Indicators. Journal of Chemical & Engineering Data. 2020; 65 (12):5844-5861.
Chicago/Turabian StyleIsmail I. I. Alkhatib; Margarida L. Ferreira; Carlos G. Alba; Daniel Bahamon; Fèlix Llovell; Ana B. Pereiro; João M. M. Araújo; Mohammad R.M. Abu-Zahra; Lourdes F. Vega. 2020. "Screening of Ionic Liquids and Deep Eutectic Solvents for Physical CO2 Absorption by Soft-SAFT Using Key Performance Indicators." Journal of Chemical & Engineering Data 65, no. 12: 5844-5861.
Within the context of the development of novel separation processes to separate hydrofluorocarbons (HFCs) in the use of refrigerants, this work combines new and recent experimental data with accurate modeling using the soft-SAFT equation of state to assess the feasibility of the absorption of R134a in new fluorinated ionic liquids (FILs) and deep eutectic solvents (DESs). The study is divided in three parts: in a first stage, the solubility of four F-gases with a different number of fluorine atoms, R14, R23, R32, and R134a in the benchmark FIL [C2mim][Tf2N], was measured at low pressures. The results have been modeled with soft-SAFT, including R125 for comparison, in an effort to relate the changes of solubility with the structures of these gases. On the basis of the higher solubility of R134a, this refrigerant has been selected to develop soft-SAFT models capable of describing its solubility in a variety of alternative FILs. An analysis of the binary parameters utilized, remarking their differences related to the molecular model of each FIL, is given. Finally, the study is completed by the synthesis of six DESs based on the combination of [C2mim][Cl] as hydrogen-bond acceptor (HBA), and [HC4F9CO2] and [HC4F9SO3] as hydrogen-bond donors (HBDs) to study the solubility of R134a from an experimental–theoretical approach. New experimental data, including density, viscosity, and F-gas solubility, are provided for these systems. The more rigorous two-compound approach has been used to describe the DESs, increasing the transferability of the models. A novel methodology is proposed to obtain the description of the solubility of R134a in [C2mim][Cl]:[HC4F9SO3] based on the transferability of the soft-SAFT parameters. From the theoretical description, it is possible to predict the refrigerant solubility at different DES proportions, as well as the density of the pure DES.
Daniel Jovell; Sergi B. Gómez; Malgorzata E. Zakrzewska; Ana V. M. Nunes; João M. M. Araújo; Ana B. Pereiro; Fèlix Llovell. Insight on the Solubility of R134a in Fluorinated Ionic Liquids and Deep Eutectic Solvents. Journal of Chemical & Engineering Data 2020, 65, 1 .
AMA StyleDaniel Jovell, Sergi B. Gómez, Malgorzata E. Zakrzewska, Ana V. M. Nunes, João M. M. Araújo, Ana B. Pereiro, Fèlix Llovell. Insight on the Solubility of R134a in Fluorinated Ionic Liquids and Deep Eutectic Solvents. Journal of Chemical & Engineering Data. 2020; 65 (10):1.
Chicago/Turabian StyleDaniel Jovell; Sergi B. Gómez; Malgorzata E. Zakrzewska; Ana V. M. Nunes; João M. M. Araújo; Ana B. Pereiro; Fèlix Llovell. 2020. "Insight on the Solubility of R134a in Fluorinated Ionic Liquids and Deep Eutectic Solvents." Journal of Chemical & Engineering Data 65, no. 10: 1.
The environmental impact generated by fluorinated gases (F-gases) makes essential the development of green technologies to mitigate them. In this context, fluorinated ionic liquids (FILs) have emerged as an alternative absorbent due to their unique and exceptional properties. In this work, a COSMO-based/Aspen Plus technology was applied to evaluate the performance of FILs as absorbents in process scale of two F-gases: 1,1,1,2-tetrafluoroethane (R-134a) and difluoromethane (R-32). The operating units of a mixture Argon and HFC at two different partial pressures were modeled using Aspen Plus. Results of the absorption column in equilibrium mode revealed that the behavior of FILs is similar in the same conditions when mass units are considered, reaching higher efficiencies in the case of absorbing R-134a at high HFC partial pressures. Then, rigorous calculations of the absorption column demonstrated a kinetic control in the case of FILs with high viscosity. Higher differences on FILs behavior were found with rigorous calculations, presenting 3 FILs the best behavior among the others. Last, it was evaluated the whole process including regeneration stage in near industrial conditions. Operating conditions on the absorption column were optimized with a column of 10 m tall and diameter ranging 1.1-1.2 m at 10 bar of total pressure reaching a 90% of HFC recovery with L/G ranges between 6-10 (mass units). Last, the preliminary economic analysis revealed an operating cost to recover the 90% of HFC of 70 $/ton (R-134a) and 130 $/ton (R-32) with the FIL that revealed the best behavior, 1-ethyl-3-methylimidazolium triflate [C2C1Im][CF3SO3].
Julio Eduardo Sosa; Rubén Santiago; Daniel Hospital-Benito; Margarida Costa Gomes; João M. M. Araújo; Ana B. Pereiro; José Palomar. Process Evaluation of Fluorinated Ionic Liquids as F-Gas Absorbents. Environmental Science & Technology 2020, 54, 1 .
AMA StyleJulio Eduardo Sosa, Rubén Santiago, Daniel Hospital-Benito, Margarida Costa Gomes, João M. M. Araújo, Ana B. Pereiro, José Palomar. Process Evaluation of Fluorinated Ionic Liquids as F-Gas Absorbents. Environmental Science & Technology. 2020; 54 (19):1.
Chicago/Turabian StyleJulio Eduardo Sosa; Rubén Santiago; Daniel Hospital-Benito; Margarida Costa Gomes; João M. M. Araújo; Ana B. Pereiro; José Palomar. 2020. "Process Evaluation of Fluorinated Ionic Liquids as F-Gas Absorbents." Environmental Science & Technology 54, no. 19: 1.
Nowadays, pharmaceutical companies are facing several challenges with the development and approval of new biological products. The unique properties of several fluorinated ionic liquids (FILs), such as their high surfactant power in aqueous solutions, their chemical and biological stability, and low toxicity, favor their application in the pharmaceutical industry. Furthermore, the numerous combinations between cations and anions, in the FILs design, enlarge the possibilities to construct a successful delivery system. Several FILs also proved to not affect the activity, stability, and secondary structure of the therapeutic protein lysozyme. This work aims to study the aggregation behavior of distinct FILs in the protein suitable medium, in the presence or absence of lysozyme. Besides, different incubation conditions were tested to guarantee the optimal enzymatic activity of the protein at more stable delivery systems. Following the optimization of the incubation conditions, the quantification of the encapsulated lysozyme was performed to evaluate the encapsulation efficiency of each FIL-based system. The release of the protein was tested applying variables such as time, temperature, and ultrasound frequency. The experimental results suggest that the aggregation behavior of FILs is not significantly influenced by the protein and/or protein buffer and supports their application for the design of delivery systems with high encapsulation efficiencies, maintaining the biological activity of either encapsulated and released protein.
N. Vieira; P. Castro; D. Marques; J. Araújo; A. Pereiro. Tailor-Made Fluorinated Ionic Liquids for Protein Delivery. Nanomaterials 2020, 10, 1594 .
AMA StyleN. Vieira, P. Castro, D. Marques, J. Araújo, A. Pereiro. Tailor-Made Fluorinated Ionic Liquids for Protein Delivery. Nanomaterials. 2020; 10 (8):1594.
Chicago/Turabian StyleN. Vieira; P. Castro; D. Marques; J. Araújo; A. Pereiro. 2020. "Tailor-Made Fluorinated Ionic Liquids for Protein Delivery." Nanomaterials 10, no. 8: 1594.
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.
Paulo J. Castro; Andres E. Redondo; Julio E. Sosa; Malgorzata Ewa Zakrzewska; Ana V. M. Nunes; João M. M. Araújo; Ana B. Pereiro. Absorption of Fluorinated Greenhouse Gases in Deep Eutectic Solvents. Industrial & Engineering Chemistry Research 2020, 59, 13246 -13259.
AMA StylePaulo J. Castro, Andres E. Redondo, Julio E. Sosa, Malgorzata Ewa Zakrzewska, Ana V. M. Nunes, João M. M. Araújo, Ana B. Pereiro. Absorption of Fluorinated Greenhouse Gases in Deep Eutectic Solvents. Industrial & Engineering Chemistry Research. 2020; 59 (29):13246-13259.
Chicago/Turabian StylePaulo J. Castro; Andres E. Redondo; Julio E. Sosa; Malgorzata Ewa Zakrzewska; Ana V. M. Nunes; João M. M. Araújo; Ana B. Pereiro. 2020. "Absorption of Fluorinated Greenhouse Gases in Deep Eutectic Solvents." Industrial & Engineering Chemistry Research 59, no. 29: 13246-13259.
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 Toth or dual‐site Langmuir equations or as an exponential function of the adsorption potential under 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 F‐gases into a single one for each AC. R‐32 is the F‐gas more adsorbed by all adsorbents, followed by R‐134a, and by R‐125. All ACs are selective for R‐125 in R‐410A commercial refrigerants, specially 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. This article is protected by copyright. All rights reserved.
Julio E. Sosa; Carine Malheiro; Rui. P. P.L. Ribeiro; Paulo J. Castro; Manuel M. Piñeiro; João M. M. Araújo; Frédéric Plantier; José P. B. Mota; Ana B. Pereiro. Adsorption of fluorinated greenhouse gases on activated carbons: evaluation of their potential for gas separation. Journal of Chemical Technology & Biotechnology 2020, 95, 1892 -1905.
AMA StyleJulio E. Sosa, Carine Malheiro, Rui. P. P.L. Ribeiro, Paulo J. Castro, Manuel M. Piñeiro, João M. M. Araújo, Frédéric Plantier, José P. B. Mota, Ana B. Pereiro. Adsorption of fluorinated greenhouse gases on activated carbons: evaluation of their potential for gas separation. Journal of Chemical Technology & Biotechnology. 2020; 95 (7):1892-1905.
Chicago/Turabian StyleJulio E. Sosa; Carine Malheiro; Rui. P. P.L. Ribeiro; Paulo J. Castro; Manuel M. Piñeiro; João M. M. Araújo; Frédéric Plantier; José P. B. Mota; Ana B. Pereiro. 2020. "Adsorption of fluorinated greenhouse gases on activated carbons: evaluation of their potential for gas separation." Journal of Chemical Technology & Biotechnology 95, no. 7: 1892-1905.
We present new experimental and modelling data concerning imidazolium based-FILs synthesized with a hydroxyl group in the end of the cationic hydrogenated side chain and compared them with the analogous non-functionalized FILs in order to verify their suitability in the biomedical field. The thermophysical and thermodynamic properties of the neat compounds and the self-aggregation behaviour of FILs in aqueous solutions were measured and compared with theoretical results from the soft-SAFT equation of state, in good agreement with each other. Results showed that the presence of the hydroxyl group increases the density and viscosity of pure compounds and aqueous mixtures, whereas the thermal stability, melting, free volume, ionicity and self-aggregation behaviour decrease. These properties are improved with respect to the conventional perfluorosurfactants for the desired application, due to the full miscibility in water and the promising improved biocompatibility.
Margarida L. Ferreira; João M.M. Araújo; Lourdes F. Vega; Fèlix Llovell; Ana B. Pereiro. Functionalization of fluorinated ionic liquids: A combined experimental-theoretical study. Journal of Molecular Liquids 2020, 302, 112489 .
AMA StyleMargarida L. Ferreira, João M.M. Araújo, Lourdes F. Vega, Fèlix Llovell, Ana B. Pereiro. Functionalization of fluorinated ionic liquids: A combined experimental-theoretical study. Journal of Molecular Liquids. 2020; 302 ():112489.
Chicago/Turabian StyleMargarida L. Ferreira; João M.M. Araújo; Lourdes F. Vega; Fèlix Llovell; Ana B. Pereiro. 2020. "Functionalization of fluorinated ionic liquids: A combined experimental-theoretical study." Journal of Molecular Liquids 302, no. : 112489.
Graphene is considered a promising substance in applications related to the capture and reduction of the environmental impact of fluorinated gases. However, further research is still required to explore all related possibilities. In this work, the potential use in this context of nanofluids (NFs), obtained by dispersing graphene nanosheets in fluorinated ionic liquids (FILs) is investigated. As a starting step, a thermal and structural characterization for this type of IoNanofluids (IoNFs) is presented. The highly nanostructured nature of FILs has been recently demonstrated. The presence of fluorinated moieties is responsible for enhancing the accommodation of solutes such as small gases. The strong tendency to self-assemble forming continuous and supramolecular structures, and the versatility to rearrange in several conformational features allows the stabilization of nano colloidal systems. It is essential to perform a comprehensive study of their structural features to understand the behavior of this type of heterogeneous systems. Therefore, we present screening on the phase and structural behavior of these novel IoNFs to discover and develop optimized systems where FILs turn out to be advantageous. Thermogravimetric analysis (TGA) was employed to evaluate IoNFs mass losses with temperature, and their solid–fluid phase transitions were located using a differential scanning calorimeter (DSC). Their rheological properties were also determined through oscillatory experiments, obtaining the viscous and loss moduli. In addition, the structural percolation transition was also identified.
C. Hermida-Merino; A.B. Pereiro; J.M.M. Araújo; C. Gracia-Fernández; Javier P. Vallejo; Luis Lugo; M.M. Piñeiro. Graphene IoNanofluids, Thermal and Structural Characterization. Nanomaterials 2019, 9, 1549 .
AMA StyleC. Hermida-Merino, A.B. Pereiro, J.M.M. Araújo, C. Gracia-Fernández, Javier P. Vallejo, Luis Lugo, M.M. Piñeiro. Graphene IoNanofluids, Thermal and Structural Characterization. Nanomaterials. 2019; 9 (11):1549.
Chicago/Turabian StyleC. Hermida-Merino; A.B. Pereiro; J.M.M. Araújo; C. Gracia-Fernández; Javier P. Vallejo; Luis Lugo; M.M. Piñeiro. 2019. "Graphene IoNanofluids, Thermal and Structural Characterization." Nanomaterials 9, no. 11: 1549.
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.
Julio E. Sosa; Rui P. P. L. Ribeiro; Paulo J. Castro; José P. B. Mota; João M. M. Araújo; Ana B. Pereiro. Absorption of Fluorinated Greenhouse Gases Using Fluorinated Ionic Liquids. Industrial & Engineering Chemistry Research 2019, 58, 20769 -20778.
AMA StyleJulio E. Sosa, Rui P. P. L. Ribeiro, Paulo J. Castro, José P. B. Mota, João M. M. Araújo, Ana B. Pereiro. Absorption of Fluorinated Greenhouse Gases Using Fluorinated Ionic Liquids. Industrial & Engineering Chemistry Research. 2019; 58 (45):20769-20778.
Chicago/Turabian StyleJulio E. Sosa; Rui P. P. L. Ribeiro; Paulo J. Castro; José P. B. Mota; João M. M. Araújo; Ana B. Pereiro. 2019. "Absorption of Fluorinated Greenhouse Gases Using Fluorinated Ionic Liquids." Industrial & Engineering Chemistry Research 58, no. 45: 20769-20778.
Mixing ionic liquids (as well as mixing an inorganic salt in an ionic liquid) constitutes an easy, elegant methodology for obtaining new ionic materials. In this study, 3 ionic liquids (ILs) sharing a common cation were synthesized and mixed in 9 different proportions giving rise to 27 binary mixtures. Specifically, 1-butyl-3-methylimidazolium nitrate, [C4C1Im][NO3], 1-butyl-3-methylimidazolium chloride, [C4C1Im]Cl, and 1-butyl-3-methylimidazolium methanesulfonate, [C4C1Im][CH3SO3], were synthesized and characterized. They all share 1-butyl-3-methylimidazolium as the common archetypal cation. None of them (or any of their binary mixtures) is liquid at room temperature (T = 298.15 K), and two of them are only in the liquid state above temperatures of 343–353 K. Despite belonging to commonly used families of ILs, their handling and the study of their liquid properties (neat and mixtures) have become particularly difficult, mainly because of their tendency to solidify and their high viscosity (caused by hydrogen-bonded networks). The main goal of this work is to evaluate the thermal, dynamic, and volumetric properties of these compounds and their mixtures as well as the solid–liquid equilibria of their binary mixtures. Thermal properties, such as melting and glass-transition temperatures, were determined or calculated. Therefore, both density and viscosity have been measured and were used for the calculation of the isobaric thermal expansion coefficient, molar volumes, excess molar volumes, and viscosity deviations to linearity.
Nicole S. M. Vieira; Isabel Vazquez; João M. M. Araújo; Natalia V. Plechkova; Kenneth R. Seddon; Luís P. N. Rebelo; Ana B. Pereiro. Physicochemical Characterization of Ionic Liquid Binary Mixtures Containing 1-Butyl-3-methylimidazolium as the Common Cation. Journal of Chemical & Engineering Data 2019, 64, 4891 -4903.
AMA StyleNicole S. M. Vieira, Isabel Vazquez, João M. M. Araújo, Natalia V. Plechkova, Kenneth R. Seddon, Luís P. N. Rebelo, Ana B. Pereiro. Physicochemical Characterization of Ionic Liquid Binary Mixtures Containing 1-Butyl-3-methylimidazolium as the Common Cation. Journal of Chemical & Engineering Data. 2019; 64 (11):4891-4903.
Chicago/Turabian StyleNicole S. M. Vieira; Isabel Vazquez; João M. M. Araújo; Natalia V. Plechkova; Kenneth R. Seddon; Luís P. N. Rebelo; Ana B. Pereiro. 2019. "Physicochemical Characterization of Ionic Liquid Binary Mixtures Containing 1-Butyl-3-methylimidazolium as the Common Cation." Journal of Chemical & Engineering Data 64, no. 11: 4891-4903.
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 was 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.
Julio E. Sosa; João M.M. Araújo; Eliseo Amado-González; Ana B. Pereiro. Separation of azeotropic mixtures using protic ionic liquids as extraction solvents. Journal of Molecular Liquids 2019, 297, 111733 .
AMA StyleJulio E. Sosa, João M.M. Araújo, Eliseo Amado-González, Ana B. Pereiro. Separation of azeotropic mixtures using protic ionic liquids as extraction solvents. Journal of Molecular Liquids. 2019; 297 ():111733.
Chicago/Turabian StyleJulio E. Sosa; João M.M. Araújo; Eliseo Amado-González; Ana B. Pereiro. 2019. "Separation of azeotropic mixtures using protic ionic liquids as extraction solvents." Journal of Molecular Liquids 297, no. : 111733.
This work focuses on the design and development of fluorinated ionic liquids (FILs) as alternatives to perfluorocarbons (PFCs), widely used in industrial applications. A combined theoretical-experimental approach has been used to characterize ionic liquids (ILs), considering their thermodynamic behaviour in the presence of atmospheric gases (oxygen (O2), nitrogen (N2) and carbon dioxide (CO2)). The selected ILs are based on perfluorobutanesulfonate ([C4F9SO3]−), perfluoropentanoate ([C4F9CO2]−), trifluoromethanesulfonate ([CF3SO3]−) and trifluoroacetate ([CF3CO2]−) anions, combined with imidazolium ([CnC1Im]+, n = 2 and 4) and pyridinium ([C2C1py]+) cations. The soft-SAFT (Statistical Associating Fluid Theory) molecular-based equation of state has been used to determine the solubility behaviour of atmospheric gases in the ILs. Models for three FILs not yet parametrized, [C2C1py][C4F9SO3], [C2C1Im][C4F9CO2] and [C2C1py][C4F9CO2], have been built from transferable molecular models. The solubility of O2, N2 and CO2 in the ILs has been determined, in excellent agreement with experimental data, indicating the robustness of the soft-SAFT approach. The highest solubilities have been obtained for the FILs based on the perfluorobutanesulfonate anion ([C4F9SO3]−) and pyridinium cation ([C2C1py]+). This approach grants to evolve highly predictive IL models inherently, regarding the process of parametrization from the molecular structure, which allows to describe the behaviour of these complex systems in a faster and more robust way.
Margarida L. Ferreira; Fèlix Llovell; Lourdes F. Vega; Ana B. Pereiro; João M.M. Araújo. Systematic study of the influence of the molecular structure of fluorinated ionic liquids on the solubilization of atmospheric gases using a soft-SAFT based approach. Journal of Molecular Liquids 2019, 294, 111645 .
AMA StyleMargarida L. Ferreira, Fèlix Llovell, Lourdes F. Vega, Ana B. Pereiro, João M.M. Araújo. Systematic study of the influence of the molecular structure of fluorinated ionic liquids on the solubilization of atmospheric gases using a soft-SAFT based approach. Journal of Molecular Liquids. 2019; 294 ():111645.
Chicago/Turabian StyleMargarida L. Ferreira; Fèlix Llovell; Lourdes F. Vega; Ana B. Pereiro; João M.M. Araújo. 2019. "Systematic study of the influence of the molecular structure of fluorinated ionic liquids on the solubilization of atmospheric gases using a soft-SAFT based approach." Journal of Molecular Liquids 294, no. : 111645.
This work highlights unexpected, not so well known responses of ionic liquids and ionic liquid-containing systems, which are reported in a collective manner, as a short review. Examples include: (i) Minima in the temperature dependence of the isobaric thermal expansion coefficient of some ILs; (ii) Viscosity Minima in binary mixtures of IL + Molecular solvents; (iii) Anomalies in the surface tension within a family of ILs; (iv) The constancy among IL substitution of Cp/Vm at and around room temperature; (v) ILs as glass forming liquids; (vi) Alternate odd-even side alkyl chain length effects; (vii) Absolute negative pressures in ILs and IL-containing systems; (viii) Reversed-charged ionic liquid pairs; (ix) LCST immiscibility behavior in IL + solvent systems.
José Esperança; Mohammad Tariq; Ana B. Pereiro; João Mendes de Araújo; Kenneth R. Seddon; Luis Paulo N. Rebelo. Anomalous and Not-So-Common Behavior in Common Ionic Liquids and Ionic Liquid-Containing Systems. Frontiers in Chemistry 2019, 7, 450 .
AMA StyleJosé Esperança, Mohammad Tariq, Ana B. Pereiro, João Mendes de Araújo, Kenneth R. Seddon, Luis Paulo N. Rebelo. Anomalous and Not-So-Common Behavior in Common Ionic Liquids and Ionic Liquid-Containing Systems. Frontiers in Chemistry. 2019; 7 ():450.
Chicago/Turabian StyleJosé Esperança; Mohammad Tariq; Ana B. Pereiro; João Mendes de Araújo; Kenneth R. Seddon; Luis Paulo N. Rebelo. 2019. "Anomalous and Not-So-Common Behavior in Common Ionic Liquids and Ionic Liquid-Containing Systems." Frontiers in Chemistry 7, no. : 450.
In this work a specific family of ionic liquids, denominated fluorinated ionic liquids, with fluorine tags equal or longer than four carbon atoms, are fully characterized in order to understand their solubility and self-aggregation in aqueous solutions. The numerous combinations between cations and anions make these compounds a feasible option for the replacement of traditional and toxic surfactants used in the industrial and biomedical field. In this work, the increment of both hydrogenated and fluorinated side chain lengths, the influence of the cation headgroup (imidazolium and cholinium) as well as the difference between perfluorobutanesulfonate and perfluoropentanoate anions were studied. The liquid-liquid phase equilibria of fluorinated ionic liquids based on the perfluorobutanesulfonate anion with water were carried out. The self-aggregation behaviour of the different fluorinated ionic liquids in aqueous solutions was also determined using conductimetric titration, surface tension measurements and transmission electron microscopy. Several thermodynamic and surface parameters were obtained and used to discuss the aggregation process. These novel characterized fluorinated ionic liquids demonstrate an improved surface activity and aggregation behaviour, driven essentially by the increment of both hydrogenated and fluorinated chain lengths.
Nicole S.M. Vieira; Joana C. Bastos; Carolina Hermida-Merino; María J. Pastoriza-Gallego; Luís P.N. Rebelo; Manuel M. Piñeiro; João M.M. Araújo; Ana B. Pereiro. Aggregation and phase equilibria of fluorinated ionic liquids. Journal of Molecular Liquids 2019, 285, 386 -396.
AMA StyleNicole S.M. Vieira, Joana C. Bastos, Carolina Hermida-Merino, María J. Pastoriza-Gallego, Luís P.N. Rebelo, Manuel M. Piñeiro, João M.M. Araújo, Ana B. Pereiro. Aggregation and phase equilibria of fluorinated ionic liquids. Journal of Molecular Liquids. 2019; 285 ():386-396.
Chicago/Turabian StyleNicole S.M. Vieira; Joana C. Bastos; Carolina Hermida-Merino; María J. Pastoriza-Gallego; Luís P.N. Rebelo; Manuel M. Piñeiro; João M.M. Araújo; Ana B. Pereiro. 2019. "Aggregation and phase equilibria of fluorinated ionic liquids." Journal of Molecular Liquids 285, no. : 386-396.