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The commercialisation of the biorefinery approach involving the integration of the multi-step valorisation of low value biomass feedstock into a variety of chemicals, fuels and bioproducts is still very limited. In this context, the present work proposes an advanced methodology that comprises a cascaded approach towards wheat straw valorisation. The studied concept lies in the employment of an aqueous solution of the acidic 1-ethyl-3-methylimidazolium hydrogen sulfate ionic liquid in a selective and efficient hydrolysis of the hemicellulose fraction of wheat straw into pentoses, namely xylose and arabinose. An experimental design was utilised to search for the optimisation parameters, resulting in a maximum 80.5 wt% pentose yield in the liquor. Furthermore, the remaining solid, which contained practically all of the initial cellulose and lignin, was processed by considering two scenarios: (i) a direct enzymatic hydrolysis of the reaction solid, which yielded 75.8 mol% glucose; or (ii) a preceding extraction of lignin followed by enzymatic saccharification of the cellulose pulp, which yielded 91.3 mol% glucose. For both scenarios, lignin-rich solid fractions were obtained with distinct purities and yields. Additionally, the second scenario allowed producing a stream of value-added aromatic (phenolic) compounds. This work also overcame the challenges in IL recycling and reuse, with a simultaneous recovery of the pentoses from the reaction liquor as high as 88.6 mol%. info:eu-repo/semantics/publishedVersion

UIDB/50006/2020 The increasing application of new ionic liquids (IL) creates the need of liquid-liquid equilibria data for both miscible and quasi-immiscible systems. In this study, equilibrium concentrations at different temperatures for ionic liquid+water two-phase systems were modeled using a Quantitative-Structure-Property Relationship (QSPR) method. Data on equilibrium concentrations were taken from the ILThermo Ionic Liquids database, curated and used to make models that predict the weight fraction of water in ionic liquid rich phase and ionic liquid in the aqueous phase as two separate properties. The major modeling challenge stems from the fact that each single IL is characterized by several data points, since equilibrium concentrations are temperature dependent. Thus, new approaches for the detection of potential data point outliers, testing set selection, and quality prediction have been developed. Training set comprised equilibrium concentration data for 67 and 68 ILs in case of water in IL and IL in water modeling, respectively. SiRMS, MOLMAPS, Rcdk and Chemaxon descriptors were used to build Random Forest models for both properties. Models were subjected to the Y-scrambling test for robustness assessment. The best models have also been validated using an external test set that is not part of the ILThermo database. A two-phase equilibrium diagram for one of the external test set IL is presented for better visualization of the results and potential derivation of tie lines. authorsversion published

project CICECO-Aveiro Institute of Materials, UID/CTM/50011/2019. Associate Laboratory for Green Chemistry-LAQV, FCT Ref. UID/QUI/50006/2019. POCI-01-0145-FEDER-016403. Investigator FCT project IF/00621/2015. Programa Mais Centro under project CENTRO-07-ST24-FEDER-002008. COMPETE: PEst-C/SAU/UI0709/2011. The food industry produces significant amounts of waste, many of them rich in valuable compounds that could be recovered and reused in the framework of circular economy. The development of sustainable and cost-effective technologies to recover these value added compounds will contribute to a significant decrease of the environmental footprint and economic burden of this industry sector. Accordingly, in this work, aqueous biphasic systems (ABS) composed of cholinium-derived bistriflimide ionic liquids (ILs) and carbohydrates were investigated as an alternative process to simultaneously separate and recover antioxidants and carbohydrates from food waste. Aiming at improving the biocompatible character of the studied ILs and proposed process, cholinium-derived bistriflimide ILs were chosen, which were properly designed by playing with the cation alkyl side chain and the number of functional groups attached to the cation to be able to create ABS with carbohydrates. These ILs were characterized by cytotoxicity assays toward human intestinal epithelial cells (Caco-2 cell line), demonstrating to have a significantly lower toxicity than other well-known and commonly used fluorinated ILs. The capability of these ILs to form ABS with a series of carbohydrates, namely monosaccharides, disaccharides and polyols, was then appraised by the determination of the respective ternary liquid-liquid phase diagrams at 25 degrees C. The studied ABS were finally used to separate carbohydrates and antioxidants from real food waste samples, using an expired vanilla pudding as an example. With the studied systems, the separation of the two products occurs in one-step, where carbohydrates are enriched in the carbohydrate-rich phase and antioxidants are mainly present in the IL-rich phase. Extraction efficiencies of carbohydrates ranging between 89 and 92% to the carbohydrate-rich phase, and antioxidant relative activities ranging between 65 and 75% in the IL-rich phase were obtained. Furthermore, antioxidants from the IL-rich phase were recovered by solid-phase extraction, and the IL was recycled for two more times with no losses on the ABS separation performance. Overall, the obtained results show that the investigated ABS are promising platforms to simultaneously separate carbohydrates and antioxidants from real food waste samples, and could be used in further related applications foreseeing industrial food waste valorization. publishersversion published

Several molecular dynamics (MD) simulations have been performed in order to obtain structural information on ionic liquids (ILs) based on amino-acid anions. Six hydrophilic ILs containing cholinium or imidazolium cations combined with alaninate, glycinate or lysinate anions were modelled using the all-atom CL&P and OPLS-AA force fields. Both pure ILs and their aqueous solutions have been studied. The MD data have allowed us to analyse structure factors, S(q), and pair radial distributions functions, g(r), as well as aggregation patterns and specific interactions. The results have shown us that in neat amino-acid-based ILs the anions interact mainly through their carboxylate moiety with the charged centres of the cations. Both the lack of heavy atoms and the small size of the interacting centre in the anion contribute to the absence of a charge ordering peak in the structure factor functions of the corresponding ILs. In turn, their aqueous solutions reveal the existence of small ionic aggregates. The size distribution of these aggregates is strongly dependent on the solution's concentration. This fact points to the possibility of using amino-acid-based ILs as agents to promote hydrotrope effects, significant for the solubilisation and stabilization of organic molecules and macromolecules in aqueous solution.

The use of fluorinated ionic liquids (FILs) as novel materials in biological and pharmaceutical applications is an emerging research field. The knowledge of their cytotoxicity and that of 1-octanol/water partition coefficients are essential to assess their environmental risks, to estimate their toxicity and activity, or the hydrophilic/lipophilic balance, as well as to explore their properties as solvents in extraction processes or for successful drug design. The study of the cytotoxicity in four different human cell lines and the experimental measurement of the partition coefficient between 1-octanol and water (Po/w), using the slow-stirring method, were carried out for several FILs. In both studies, the effect of the cation ([C2C1Im]+, [C2C1py]+, [C4C1pyr]+, [N1112(OH)]+, or [N4444]+), the cationic alkyl side-chain length ([CnC1Im]+, with n = 2, 6, 8 or 12), and the anionic fluorinated chain length/anionic fluorinated domain size ([C4F9SO3]¯, [C8F17SO3]¯, or [N(C4F9SO3)2]¯) were analysed. The results reveal that both toxicity and partition properties are mainly influenced by the size of the cationic hydrogenated alkyl side-chain and that of the anionic fluorinated domain. The intrinsic tuneability of the FILs allows for their selection according to the lipophilic or hydrophilic character of the target biological system under consideration. The toxicity studies corroborate the biocompatible nature of some FILs tested in this work. Along, for all the FILs under study Po/w

Trabalho de Projeto do Mestrado Integrado em Engenharia Biomédica apresentado à Faculdade de Ciências e Tecnologia O registo da atividade cerebral, técnica conhecida por eletroencefalografia (EEG) é amplamente usada no diagnóstico de várias patologias, desde epilepsia, demência, perturbações de sono, monitorização da atividade cerebral e em muitas outras áreas. A sua natureza não invasiva torna-a uma técnica ideal para diagnóstico clínico e outras aplicações. Todas as aplicações têm em comum o facto de necessitarem de sinais robustos e detetados com boa sensibilidade, de forma a fornecerem resultados fiáveis. Apesar de todos os avanços efetuados na área, o registo de EEG continua a ser um desafio importante e contínuo, devido essencialmente à transmissão do sinal na interface elétrodo/pele.Atualmente a aquisição de sinais EEG utiliza geralmente os elétrodos de Ag/AgCl, compostos por um disco de prata revestidos de cloreto de prata, sendo os atuais gold standard. As suas maiores vantagens são a biocompatibilidade, a confiabilidade, a pouca suscetibilidade ao ruído e a reprodutibilidade dos sinais elétricos. Contudo, estes necessitam obrigatoriamente da aplicação de uma pasta condutora para formar uma interface condutora com o escalpe. Esta operação de colocação do gel pode demorar até 45 minutos, sendo que é necessário um técnico especializado para a realização de tal. Em exames longos, a pasta tem de ser reaplicada periodicamente, sendo esta a principal desvantagem inerente a este método. Desta forma, a aplicação autónoma e aquisição por longos períodos de tempo, apenas poderá ser conseguida prescindindo da pasta condutora.Uma possível solução é a criação de uma interface condutora, não metálica e com boa capacidade de conformação ao escalpe, que poderá constituir o revestimento de elétrodos utilizando um gel polimérico contendo um líquido iónico (ionogel). Um líquido iónico é definido como um sal que à temperatura ambiente é líquido. Estes compostos possuem propriedades únicas, nomeadamente uma pressão de vapor negligenciável, boa estabilidade térmica e química e ainda uma excelente condutividade iónica. Nesse sentido, o ionogel garantiria a condutividade elétrica desejada, sem evaporar ou libertar-se do gel. A presente dissertação descreve o desenvolvimento de elétrodo para o registo de EEG, combinando um elétrodo polimérico (desenvolvido em trabalhos anteriores) e um ionogel que o reveste. O ionogel funciona como um eletrólito, diminuindo a impedância da interface elétrodo/pele. Os objetivos do projeto centram-se no desenvolvimento de um elétrodo reprodutível e com propriedades necessárias à sua aplicação, desenvolvimento de um ionogel, caracterização do ionogel utilizado (elétrica e mecânica) e comparação do registo de EEG in vivo entre estes elétrodos e os elétrodos comerciais de Ag/AgCl. Os resultados sugerem que o ionogel desenvolvido é apropriado e eficiente no sentido em que baixa a impedância da interface elétrodo/pele, resistindo a todos os procedimentos necessários para a colocação deste. Este possui condutividades da ordem de 1x10-2 S.cm-1, imobiliza de forma eficaz o IL, com uma resistividade à compressão de cerca de 64 N/cm2. Pelos ensaios in vivo comprovou-se a fiabilidade dos elétrodos para registo de atividade cerebral, com correlação de 90% em relação aos sinais obtidos pelos elétrodos comerciais de Ag/AgCl. Recording of brain activity, a technique also known as electroencephalography (EEG), is widely used for diagnostic of several pathologies, from epilepsy and dementia to sleep disorders, for monitoring of brain activity as well as in many other areas. Its non-invasive nature makes it ideal for clinic diagnostics and other applications. All applications have in common the need of robust signals and good sensibility data acquiring, in order to provide reliable results. Despite of all the advances seen in this area, EEG recording continues to be an important and continuous challenge, mainly due to signal transmission on the electrode/skin interface.Nowadays, EEG signal acquisition normally uses Ag/AgCl electrodes composed by a silver disk covered by silver chloride, this being today’s gold standard. Their main advantages are its biocompatibility, reliability, low noise susceptibility and electric signals reproducibility. However, they necessarily need the appliance of a conductive paste to form a conductive interface with the scalp. Gel appliance can take up to 45 minutes, and can only be performed by a specialized technician. During longer exams, the paste is applied periodically, being this one inherent disadvantage of this method. Therefore, autonomous application and acquisition for long periods of time can only be achieved by dispensing the conductive paste.A possible solution is the development of a conductive interface, non-metallic and with good capacity of scalp conformation to be used in the covering of electrodes with a polymeric gel containing an ionic liquid (ionogel). An ionic liquid (IL) is defined as a salt, being liquid at room temperature. These compounds have unique properties, namely a negligible vapor pressure, good thermic and chemical stability, as well as an excellent ionic conductivity. This being said, the ionogel would assure the desirable electric conductivity, without evaporate or releasing itself from the gel. The present dissertation describes the development of an electrode for EEG recording, combining a polymeric electrode (developed in previous related works) and an ionogel that covers it up. Here, the ionogel serves as an electrolyte, diminishing electrode/skin interface’s impedance.Project’s objectives consist on the development of a reproducible electrode meeting the necessary properties for its application, the development of a capable ionogel and proper characterization (electrical and mechanical), and also the comparison of in vivo EEG recordings between this electrode and Ag/AgCl commercial electrodes.Results suggest that the ionogel is capable and efficient, once it decreases the electrode/skin interface’s impedance, resisting to all necessary procedures to a proper appliance. It possesses conductivities values around 1x10-2 S.cm-1, immobilizes the IL in an efficient manner and its resistivity to compression is around 64 N/cm2. Electrode reliability for brain activity recordings is proved by in vivo trials, with a correlation of 90% in relation to the signals obtained using Ag/AgCl commercial electrodes.

In the past several years, ionic liquids (ILs) have been at the cutting edge of the most promising science and technology. ILs not only have found applications in classical areas of knowledge but also are important candidates to solve classical problems within several societal challenges, such as clean and efficient energy, through the development of a broad swath of energy technologies, such as advanced batteries, dye-sensitized solar cells, double-layer capacitors, actuators, fuel cells, thermo-cells, and water splitting, essentially related to highly efficient carbon capture and storage technologies and resource efficiency to date. This review focuses on the application of IL methodologies to solve critical pharmaceutical problems, in particular, the low solubility and thus bioavailability of pharmaceutical compounds and the presence of polymorphs, which severely hamper the efficacy of important commercially available drugs. The development of strategies to use ILs as carriers of pharmaceutical active compounds is an extremely promising and wide avenue. Further, the synthesis of liquid salts through the discerning combination of cations and anions with several distinct pharmaceutical roles provides answers to some of today's pharmaceutical industrial challenges.

This study constitutes the first attempt to understand at the proteomic level the fungal response to ionic liquid stress. Ascomycota are able to grow in media supplemented with high concentrations of an ionic liquid, which, in turn, lead to major alterations in the fungal metabolic footprint. Herein, we analysed the differential accumulation of mycelial proteins in Aspergillus nidulans and Neurospora crassa after their exposure to two of the most commonly used ionic liquids: 1-ethyl-3-methylimidazolium chloride or cholinium chloride. Data obtained showed that numerous stress-responsive proteins ( e.g. anti-ROS defence proteins) as well as several critical biological processes and/or pathways were affected by either ionic liquid. Amongst other changes, these compounds altered developmental programmes in both fungi ( e.g. promoting the development of Hulle cells or conidiation) and led to accumulation of osmolytes, some of which may play an important role in multiple stress responses. In particular, in N. crassa , both ionic liquids increased the levels of proteins which are likely involved in the biosynthesis of unusual metabolites. These data potentially open new perspectives on ionic liquid research, furthering their conscious design and their use to trigger production of targeted metabolites. Biological significance The present study emphasises the importance of understanding ionic liquid's stress responses, crucial to further their safe large-scale usage. Knowledge of the alterations prompted at a cellular and biochemical level gives also fresh perspectives on how to employ these “novel” compounds to manipulate proteins or pathways of biotechnological value. The results presented here provide meaningful insights into the understanding of fungi stress and adaptation responses to anthropogenic chemicals used in industry.

This work is a new development of an extensive research program that is investigating for the first time shifts in the temperature of maximum density (TMD) of aqueous solutions caused by ionic liquid solutes. In the present case we have compared the shifts caused by three ionic liquid solutes with a common cation—1-ethyl-3-methylimidazolium coupled with acetate, ethylsulfate and tetracyanoborate anions—in normal and deuterated water solutions. The observed differences are discussed in terms of the nature of the corresponding anion-water interactions.

Since the approval of recombinant human insulin by FDA in 1982, more than 200 proteins are currently available for pharmaceutical use to treat a wide range of diseases. However, innovation is still required to develop effective approaches for drug delivery. Our aim is to investigate the potential use of fluorinated ionic liquids (FILs) as drug delivery systems (DDS) for therapeutic proteins. Some initial parameters need to be assessed before further studies can proceed. This work evaluates the impact of FILs on the stability, function, structure and aggregation state of lysozyme. Different techniques were used for this purpose, which included differential scanning fluorimetry (DSF), spectrophotometric assays, circular dichroism (CD), dynamic light scattering (DLS), and scanning and transmission electron microscopy (SEM/TEM). Ionic liquids composed of cholinium-, imidazolium- or pyridinium- derivatives were combined with different anions and analysed at different concentrations in aqueous solutions (below and above the critical aggregation concentration, CAC). The results herein presented show that the addition of ionic liquids had no significant effect on the stability and hydrolytic activity of lysozyme. Moreover, a distinct behaviour was observed in DLS experiments for non-surfactant and surfactant ionic liquids, with the latter encapsulating the protein at concentrations above the CAC. These results encourage us to further study ionic liquids as promising tools for DDS of protein drugs.

Despite many previous important contributions to the characterization of the liquid-liquid phase behavior of ionic liquids (ILs) plus water systems, a gap still exists as far as the effect of isomers (of ILs) is concerned. Therefore, in this work, a comprehensive study of the liquid-liquid equilibria between water and isomeric pyridinium-based ionic liquids has been performed. Atmospheric pressure mutual solubilities between water and pyridinium-based ionic liquids combined with the common anion bis[(trifluoromethyl)sulfonyl]imide were experimentally determined between (288.15 and 318.15) K. The main goal of this work is to study the isomeric effects on the pyridinium-based cation, namely, the structural and positional isomerism, as well as the alkyl side chain length. To the best of our knowledge, the influence of both structural and positional isomerism on the liquid-liquid behavior in ionic-liquid-water-containing systems is an unexplored field and is here assessed for the first time. Moreover, from the experimental solubility data, several infinite dilution molar thermodynamic functions of solution, namely, the Gibbs energy, the enthalpy, and the entropy, were estimated and discussed. In addition, aiming at gathering a broader picture of the underlying thermodynamic solvation phenomenon, molecular dynamics simulations were also carried out for the same experimental systems.

By employing (1)H NMR spectroscopy and molecular simulations, we provide an explanation for recent observations that the aqueous solubilities of ionic liquids exhibit salting-out to salting-in regimes upon addition of distinct inorganic salt ions. Using a typical ionic liquid [1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide], we observed the existence of preferential specific interactions between the low electrical charge density ("apolar moiety") parts of the ionic liquid cation and the inorganic salts. These a priori unexpected interactions become increasingly favorable as one moves from salting-out to salting-in effects. More specifically, this interpretation is validated by distinct aqueous solution (1)H NMR data shifts in the ionic liquid cation upon inorganic salt addition. These shifts, which are well noted in the terminal and preterminal hydrogens of the alkyl chain appended to the imidazolium ring, correlate quantitatively with solubility data, both for cases where the nature of inorganic salt is changed, at constant concentration, and for those where the concentration of a given inorganic salt is varied. Molecular simulations have also been performed permitting us to garner a broader picture of the underlying mechanism and structure of this complex solvation phenomenon. These findings can now be profitably used to anticipate solution behavior upon inorganic salt addition well beyond the specificity of the ionic liquid solutions, i.e., for a diversity of distinct solutes differing in chemical nature.

The fascinating, complex behavior of ionic liquids is analyzed using a molecular perspective that emphasizes the doubly dual nature of ionic liquids underlying the existence of cations and anions forming high- and low-charge-density regions. Our work bridges the liquid, gas, and solid phases spanning 5 years of research on themes as diverse as the vaporization, liquid-liquid demixing, solidification, and thermophysical behavior of ionic liquids and their mixtures and solutions.

Marked solubility differences of nicotine in the ionic liquids [C(2)mim][NTf(2)], [C(2)mim][EtOSO(3)], and [C(n)mim]Cl, 6or= nor= 10, are observed through the analysis of the corresponding phase diagrams. These show the potential of commonly used ionic liquids to extract and purify this important compound. From a fundamental standpoint, the generally enhanced solubility of nicotine in these ionic liquids as compared to that of aromatic and aliphatic hydrocarbons can be assigned to the presence of the aromatic pyridine ring and the large aliphatic N-methyl-pyrrolidine residue.

The effects of the addition of three inorganic salts, namely, NaCl, Na(2)SO(4), and Na(3)PO(4), on the liquid-liquid (L-L) phase diagram of aqueous solutions containing the model ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF(4)], were investigated. All three inorganic salts trigger salting-out effects, leading to significant upward shifts of the L-L demixing temperatures of the systems. The magnitude of the shifts depends on both the water-structuring nature of the salt and its concentration; that is, the effects are correlated with the ionic strength of the solution and the Gibbs free energy of hydration of the inorganic salt. The pH effect and the occurrence of salt precipitation in concentrated solutions are also discussed.

Significant antiproliferative effects against various tumor cell lines were observed with novel ampicillin salts as ionic liquids. The combination of anionic ampicillin with appropriate ammonium, imidazolium, phosphonium, and pyridinium cations yielded active pharmaceutical ingredient ionic liquids (API-ILs) that show potent antiproliferative activities against five different human cancer cell lines: T47D (breast), PC3 (prostate), HepG2 (liver), MG63 (osteosarcoma), and RKO (colon). Some API-ILs showed IC50 values between 5 and 42nM, activities that stand in dramatic contrast to the negligible cytotoxic activity level shown by the ampicillin sodium salt. Moreover, very low cytotoxicity against two primary cell linesskin (SF) and gingival fibroblasts (GF)indicates that the majority of these API-ILs are nontoxic to normal human cell lines. The most promising combination of antitumor activity and low toxicity toward healthy cells was observed for the 1-hydroxyethyl-3-methylimidazolium-ampicillin pair ([C2OHMIM][Amp]), making this the most suitable lead API-IL for future studies. authorsversion published

In the present chapter, we describe different types of investigation carried out by research groups based at CQE/IST/UTL and ITQB/UNL and their ramifications in terms of surface science. Most of the work is focused on the characterization of ionic liquids (ILs) (both by experimental and theoretical techniques) and on the different types of interaction that they can experience in the bulk or at an interface. Studies in the bulk include the analysis of the aggregation behavior (micelle formation) in aqueous solution of dialkylpyrrolidinium bromide ILs using isothermal titration calorimetry. Other studies involve the exploration of the structural organization of 1-alkyl-3-methylimidazolium chloride ILs in aqueous solution. Studies at the IL-- air interface include surface tension measurements along the 1-alkyl-3-methylimidazolium bistriflimide homologous series over very wide temperature ranges. The results were used to validate other methodologies aimed at the estimation of the (hypothetical) critical and boiling point temperatures of ILs. Finally, the adsorption behavior of ILs at solid surfaces (gold, glass) was studied using different experimental techniques (quartz crystal microbalance with dissipation (QCM-D) and atomic force microscopy (AFM)). The results yielded a fascinating picture of the complex surface behavior of ILs at the solid--liquid interface. Wiley Online library

The relative ability of cholinium-([Ch](+))-based salts, including ionic liquids (ILs), to form biocompatible aqueous biphasic systems (ABS) with polyethylene glycols (PEGs) was deeply scrutinized in this work. Aqueous solutions of low molecular weight PEG polymers (400, 600, and 1000 g mol(-1)) and [Ch](+) salts of chloride, acetate, bicarbonate, glycolate, lactate, dihydrogenphosphate, dihydrogencitrate, and bitartrate can undergo liquid-liquid demixing at certain concentrations of the phase-forming components and at several temperatures. Cholinium butanoate and propanoate were also studied; however, these long alkyl side chain ILs are not able to promote an immiscibility region with PEG aqueous solutions. The ternary liquid-liquid phase diagrams, binary water activities, PEG-salt and salt-H2O solubility data, and binary and ternary excess enthalpies estimated by COSMO-RS (COnductor-like Screening MOdel for Realistic Solvation) were used to obtain new insights into the molecular-level mechanisms responsible for phase separation. Instead of the expected and commonly reported salting-out phenomenon induced by the [Ch](+) salts over the polymer, the formation of PEG-[Ch](+) salt ABS was revealed to be an end result of a more intricate molecular scenario. The multifaceted approach employed here reveals that the ability to promote an ABS is quite different for the higher melting salts vs. the lower melting or liquid ILs. In the latter systems, the ABS formation seems to be controlled by the interplay of the relative strengths of the ion-ion, ion-water, ion-PEG, and water-PEG interactions, with a significant contribution from specific hydrogen-bonding between the IL anion and the PEG hydroxyl groups.

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The dissolution of uracil-a pyrimidine nucleic acid base-in the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C2mim][CH3COO]) has been investigated by methods of (1)H and (13)C NMR spectroscopy, (1)H-(1)H NOESY NMR spectroscopy, and quantum chemical calculations. The uracil-[C2mim][CH3COO] interactions that define the dissolution mechanism comprise the hydrogen bonds between the oxygen atoms of the acetate anion and the hydrogen atoms of the N1-H and N3-H groups of uracil and also the hydrogen bonds between the most acidic aromatic hydrogen atom (H2) of the imidazolium cation and the oxygen atoms of the carbonyl groups of uracil. The bifunctional solvation nature of the ionic liquid can be inferred from the presence of interactions between both ions of the ionic liquid and the uracil molecule. The location of such interaction sites was revealed using NMR data ((1)H and (13)C chemical shifts both in the IL and in the uracil molecule), complemented by DFT calculations. NOESY experiments provided additional evidence concerning the cation-uracil interactions.

In this communication, we report a new method for the isolation of betulin, a triterpenoid with interesting pharmacological activities, from birch outer bark. Remarkably high purity betulin raw extracts were obtained, ca. 95 wt%, through microwave assisted extraction with limonene. This saves time and energy when compared to the conventional methods.

In order to overcome the problems associated with low water solubility, and consequently low bioavailability of active pharmaceutical ingredients (APIs), herein we explore a modular ionic liquid synthetic strategy for improved APIs. Ionic liquids containing L-ampicillin as active pharmaceutical ingredient anion were prepared using the methodology developed in our previous work, using organic cations selected from substituted ammonium, phosphonium, pyridinium and methylimidazolium salts, with the intent of enhancing the solubility and bioavailability of L-ampicillin forms. In order to evaluate important properties of the synthesized API-ILs, the water solubility at 25 degrees C and 37 degrees C (body temperature) as well as octanol-water partition coefficients (K-ow's) and HDPC micelles partition at 25 degrees C were measured. Critical micelle concentrations (CMC's) in water at 25 degrees C and 37 degrees C of the pharmaceutical ionic liquids bearing cations with surfactant properties were also determined from ionic conductivity measurements. (C) 2013 Elsevier B.V. All rights reserved.

Density and viscosity data of the N-alkyl-N,N-dimethyl-N-(2-hydroxyethyl)ammonium bis(trifluoromethylsulfonyl)imide ionic liquids homologous series [N(1 1 n 2(OH))][Ntf(2)] with n=1, 2, 3, 4 and 5 have been measured at atmospheric pressure in the 283

For the first time, two distinct trends are clearly evidenced for the enthalpies and entropies of vaporization along the [Cnmim][Ntf2] ILs series. The trend shifts observed for Δ(l)(g)H(m)(o) and Δ(l)(g)S(m)(o), which occur at [C6mim][Ntf2], are related to structural modifications. The thermodynamic results reported in the present article constitute the first quantitative experimental evidence of the structural percolation phenomenon and make a significant contribution to better understanding of the relationship among cohesive energies, volatilities, and liquid structures of ionic liquids. A new Knudsen effusion apparatus, combined with a quartz crystal microbalance, was used for the high-accuracy volatility study of the 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide series ([Cnmim][Ntf2], where n = 2, 3, 4, 5, 6, 7, 8, 10, 12). Vapor pressures in the (450–500) K temperature range were measured, and the molar standard enthalpies, entropies, and Gibbs energies of vaporization were derived. The thermodynamic parameters of vaporization were reported, along with molecular dynamic simulations of the liquid phase structure, allowing the establishment of a link between the thermodynamic properties and the percolation phenomenon in ILs.

Ionic liquids were initially proposed as replacements for conventional organic solvents; however, their chemistry has developed remarkably and offers unexpected opportunities in numerous fields, ranging from electrochemistry to biology. As a consequence of ionic liquids advancing towards potential and actual applications, a comprehensive determination of their environmental, health and safety impact is now required. This critical review aims to present an overview of the current understanding of the toxicity and environmental impact of the principal ionic liquid groups, and highlights some emerging concerns. Each cation type is considered separately, examining the significance of the biological data, and identifying the most critical questions, some yet unresolved. The need for more, and more detailed, studies is highlighted (176 references).

A set of 1-alkyl-3-methylimidazolium alkanesulfonate ionic liquids, [C(n)mim][C(k)SO(3)], formed by the variation of the alkyl chain lengths both in the cation and the anion (n = 1-6, 8, or 10; k = 1-4, or 6), was synthesised, with sixteen of them being novel. The ionic liquids were characterised by (1)H and (13)C NMR spectroscopy, and mass spectrometry. Their viscosities and densities as a function of temperature, as well as melting points and decomposition temperatures, were determined. The molecular volumes, both experimental and calculated, were found to depend linearly on the sum (n + k).

The current study focuses on 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, [bmim][NTf2], and 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, [hmim][NTf2]. The objective is to study the influence of pressure as well as that of the cation’s alkyl chain length on several properties of this type of ionic liquids. Speed of propagation of ultrasound waves and densities in pure ionic liquids (ILs) as a function of temperature and pressure have been determined. Several other thermodynamic properties such as compressibilities, expansivities and heat capacities have been obtained. Speed of sound measurements have been carried out in broad ranges of temperature (283

Ionic liquids have been explored as attractive alternative media for CO2 separation not only due to their low volatility but also due to their highly tuneable nature. Aiming at designing highly efficient liquid phases for flue gas separation and natural gas purification, this work focuses on the use of binary ionic liquid mixtures containing sulfate and/or cyano-functionalized anions. Several mixtures were prepared and their gas transport properties through supported ionic liquid membranes (SILMs) were investigated. The thermophysical properties of these mixtures, namely viscosity and density (data presented and discussed in ESI), were also measured so that trends between transport properties and thermophysical properties could be evaluated. The results obtained indicate that depending on the anions mixed, membranes with fine-tuned gas permeabilities, diffusivities and solubilities can be obtained. Additionally, SILMs prepared with these ionic liquid mixtures are on the upper bound of the CO2/N-2 separation, or even may surpass it, indicating their potential for separating CO2 in low-pressure post-combustion processes. Overall, the use of ionic liquid mixtures combining the most selective anions with the least viscous anions is a highly promising strategy to design advanced engineered liquid phases for CO2 separation membranes.