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Projeto de investigação
Exploiting the Potential of Surface Active Ionic Liquids: Fluorinated Ionic Liquids Meet Biomolecules
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Understanding the phase and solvation behavior of fluorinated ionic liquids
Publication . Ferreira, Margarida L.; Vieira, Nicole S. M.; Castro, Paulo J.; Vega, Lourdes F.; Araújo, João M. M.; Pereiro, Ana B.; LAQV@REQUIMTE; DQ - Departamento de Química; Elsevier
Fluorinated ionic liquids (FILs) are defined as molecules having fluorinated tags equal to or longer than 4 carbon atoms in the anion and/or cation structures. They present nanosegregated domains making them 3-in-1 solvents with exceptional properties, including an attractive solubility power. This work is an important contribution towards understanding the current research on the phase behavior of FILs, which may be used as task-specific materials for industrial applications. An overview of the main works published in the last two decades is presented, concerning gas solubility in FILs, the application of membranes to improve the gas absorption in FILs, and the use of modeling approaches to ease the application of FILs in gas capture and separation processes, with emphasis on the relationship between the structural properties and their performance. Contributions concerning the liquid-liquid and solid-liquid equilibria behavior of FILs, including the liquid-liquid equilibria (LLE) of FILs in water and perfluoroalkanes, and the solid-liquid equilibria (SLE) of solid FILs in water and mixtures of FILs are also presented. Regarding the absorption of gases in FILs, a careful analysis of the published works reveals that: (1) an optimal density of fluorine atoms in FILs structure is required to positively impact the absorption of different gases, (2) the functionalization of membranes can be also a useful method to improve the performance in separation processes, and (3) modeling tools can ease the screening of the features that promote the absorption of gases by FILs. The study of FILs LLE showed a rich phase behavior with water and perfluoroalkanes and the enhanced surfactant power of FILs, which is highly dependent on the length of the hydrogenated and fluorinated side chains. Finally, studying the SLE of FILs mixtures allowed the formation of deep eutectic systems that enlarges the applicability of FILs.
Understanding the Absorption of Fluorinated Gases in Fluorinated Ionic Liquids for Recovering Purposes Using Soft-SAFT
Publication . Ferreira, Margarida L.; Araújo, João M. M.; Vega, Lourdes F.; Pereiro, Ana B.; LAQV@REQUIMTE; DQ - Departamento de Química; ACS - American Chemical Society
It is proven that fluorinated gases (F-gases) have a vast impact on climate change due to their high global warming potential. Hence, it is imperative to search for new molecules to replace them in current applications, as well as technologies to capture, recover, and recycle F-gases to avoid their emissions to the atmosphere. One of the attractive technologies for this purpose is to absorb them in fluorinated ionic liquids (FILs), given their solubilization power. However, the complexity of FILs and the time-consuming experimental methodologies to fully characterize them hinder their prompt usage in this urgent field. In this work, the soft-Statistical Associating Fluid Theory (soft-SAFT) Equation of State is used as a tool to investigate the solubility of six different F-gases (R-32, R-125, R-134a, R-14, R-116, R-218) in five FILs ([C2C1Im][C4F9SO3], [C2C1Im][C4F9CO2], [C2C1py][C4F9SO3], [C2(C6F13)C1Im][N(CF3SO2)2], and [C2(C6F13)C1Im][N(C2F5SO2)2]). The robustness of the soft-SAFT approach allowed the establishment of new FIL models in a simple and fast way, and the calculation of F-gases solubility in them, in excellent agreement with existing experimental data. Once the models were assessed, a systematic study was performed regarding the structural features of FILs favoring their performance to absorb F-gases by using the soft-SAFT approach as a screening tool. It has been obtained that the solubility is favored by the presence of a perfluoroalkyl chain in the imidazolium cation, together with a bulkier anion. In all cases, [C2(C6F13)C1Im][N(C2F5SO2)2] shows a superior solubility of F-gases than the [C2(C6F13)C1Im][N(CF3SO2)2], also indicating that the addition of one carbon to the two anionic symmetric fluorinated chains contributes to the gas-philicity of the FILs. This work proves the relevance of using the soft-SAFT framework to obtain insights into the behavior of such complex systems and key trends, even when experimental data are scarce, as a step forward in assessing systems for separating and recovering F-gases.
Exploiting the Potential of Surface Active Ionic Liquids: Fluorinated Ionic Liquids meet Biomolecules
Publication . Ferreira, Margarida Lourenço; Estévez, Ana; Araújo, João; Vega Fernández, Lourdes
Proteins are macromolecules constituting all the living organisms, being classified as
versatile biopolymers, with the widest biological activities. Thus, they have a high impact in
different fields, such as the biochemical, biotechnological, chemical, pharmaceutical, and food
industries. However, their industrial applications depend on costly downstream processes to
yield proteins with high purity, stability, and activity. Moreover, the biological activity of
proteins depends on the preservation of the three-dimensional structure, which is determined
by the delicate balance between their interactions with compounds in the surrounding
environment. To surpass these challenges, ionic liquids (ILs) have emerged in the biological
field as an improved asset due to the possibility to design task-specificity materials by
selecting the anions and cations composing their structure, and fine-tuning their properties.
The surface-active ionic liquids (SAILs) are a highly recognized family of ILs with improved
surfactant behaviour. SAILs can be used in the stabilization, extraction, separation,
crystallization, and development of protein delivery systems. However, there is still a great
lack of knowledge about the interactions between SAILs and proteins, essential information
to guide the selection of the best compounds for these bottom-line applications.
In this doctoral thesis, fluorinated ionic liquids (FILs), an enhanced family of SAILs,
were used to study the interactions between IL-proteins with the aim to develop FIL-based
systems for the separation, extraction, and proteins delivery systems. To begin, a review of the
literature was performed to understand FILs properties. These compounds grant augmented
solubilization mechanisms due to the rich self-aggregation behaviour and can be designed to
be completely miscible in aqueous solutions with negligible toxicity, which aids their
performance in the biological field. Furthermore, the soft-Statistical Associating Fluid Theory
Equation of State (soft-SAFT EoS) was used to model FILs in an intuitive, robust, and reliable
way. A straightforward methodology was implemented using soft-SAFT EoS to compute the
thermophysical properties of FILs and their mixtures with various solutes. In addition, it was
investigated the influence of the structural features of FILs in their self-aggregation behaviour
in aqueous solutions. In the end, the impact of the FILs on the solubility, stability, and
interaction with different proteins was evaluated. The results of this thesis comprise a proof
of concept of the feasibility of FILs-based systems for biological, biochemical, and
pharmaceutical applications.
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COVID/BD/151919/2021