Browsing by Author "Bogel-Lukasik, Ewa"
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- Ammonium ionic liquids as green solvents for drugsPublication . Melo, Catarina I.; Lukasik, Rafal M.; Ponte, Manuel Nunes; Bogel-Lukasik, EwaA high solubility of antituberculosis antibiotic drugs: isoniazid and pyrazinecarboxamide in ammonium ionic liquids shown in this work, demonstrates the promising perspectives in the drug processing. Solid–liquid equilibrium (SLE) measurements have been made using a dynamic (synthetic) method. Thermophyscial properties such as melting point, enthalpy of fusion, temperatures of phase transitions and corresponding enthalpies for both isoniazid and pyrazinecarboxamide as well as for three ammonium salts were acquired using differential scanning calorimetry (DSC). The solubility of isoniazid in analysed ILs was found to be higher than that of pyrazinecarboxamide. Considering ammonium salts examined in this work, didecyldimethylammonium nitrate is the best solvent for both antibiotics. The solid–liquid phase equilibria were described using six different correlation equations which revealed a relatively good description with an acceptable standard deviation temperature range.
- Combination of supercritical carbon dioxide and ionic liquid in a novel assembly of carvacrolPublication . Melo, Catarina I.; Lukasik, Rafal M.; Bogel-Lukasik, EwaExploitation of neoteric solvents in the efficient total synthesis of carvacrol, an antimicrobial reagent, has been accomplished. The first reaction aimed supercritical mediated heterogeneous hydrogenation of carvone catalysed by palladium. The second step guided to an application of great salvation capacity of ionic liquids in separation of carvacrol from the post-hydrogenation mixture. The process has been completed by use of a high pressure CO2 potential to extract carvacrol from the ionic liquid reservoir.
- A favourable solubility of isoniazid, an antitubercular antibiotic drug, in alternative solventsPublication . Forte, Andreia; Melo, Catarina I.; Lukasik, Rafal M.; Bogel-Lukasik, EwaThe sufficient solubility of isoniazid in alternative solvents obtained in this work can open new perspectives in pharmaceutical processing. Solid–liquid equilibrium (SLE) measurements have been made using a dynamic (synthetic) method. The melting point and the enthalpy of fusion of isoniazid were acquired using differential scanning calorimetry (DSC). The solubility of isoniazid in bis(trifluoromethylsulfonyl)amide ionic liquids was found to be significantly lower than in the studied trifluoromethanesulfonate ionic liquid. The best solvent amongst studied for this common antibiotic against tuberculosis was discovered. The solid–liquid phase equilibria were described using the six different correlation equations which revealed relatively good description with the acceptable standard deviation temperature range.
- Ionic liquidsPublication . Lukasik, Rafal M.; Bogel-Lukasik, EwaIonic liquids (ILs) are a group of interesting compounds that have been known for more than a century, attracting major attention within the last two decades. ILs are often confused with molten salts. ILs are salts with the melting point arbitrarily determined to be below 100°C. They are composed of ions and, thus, each IL possesses unique properties that are the effect of a cation and an anion‘s nature. However, in general, ILs are characterized by a low melting point, high thermal and chemical stability, a large electrochemical window, great solvent power, nonflammability and a negligible vapor pressure. Density and viscosity, as well as many other properties, can easily be tuned as they are dependent on the chemical structure of the IL. Therefore, the ‘designer solvent‘ can be created for many applications, including biotransformation, chemical reactions (e.g., catalysis and hydrogenation), biorefinery concept, extraction and separation, and others.
- Ionic liquids as a tool for lignocellulosic biomass fractionationPublication . Lopes, André; João, Karen; Morais, Ana Rita C.; Bogel-Lukasik, Ewa; Lukasik, Rafal M.Lignocellulosic biomass composes a diversity of feedstock raw materials representing an abundant and renewable carbon source. In majority lignocellulose is constituted by carbohydrate macromolecules, namely cellulose and hemicellulose, and by lignin, a polyphenilpropanoid macromolecule. Between these biomacromolecules, there are several covalent and non-covalent interactions defining an intricate, complex and rigid structure of lignocellulose. The deconstruction of the lignocellulosic biomass makes these fractions susceptible for easier transformation to large number of commodities including energy, chemicals and material within the concept of biorefinery. Generally, the biomass pre-treatment depends on the final goal in the biomass processing. The recalcitrance of lignocellulose materials is the main limitation of its processing once the inherent costs are excessively high for the conventional pre-treatments. Furthermore, none of the currently known processes is highly selective and efficient for the satisfactory and versatile use, thus, new methodologies are still studied broadly. The ionic liquid technology on biomass processing is relatively recent and first studies were focused on the lignocellulosic biomass dissolution in different ionic liquids (ILs). The dissolution in IL drives to the structural changes in the regenerated biomass by reduction of cellulose crystallinity and lignin content contrasting to the original biomass. These findings provided ILs as tools to perform biomass pre-treatment and the advantageous use of their specific properties over the conventional pre-treatment processes. This review shows the critical outlook on the study of biomass dissolution and changes occurred in the biomass during this process as well as on the influence of several crucial parameters that govern the dissolution and further pre-treatment process. The review of currently known methods of biomass fractionation in IL and aqueous-IL mixtures is also discussed here and perspectives regarding these topics are given as well.
- Ionic liquids’ cation and anion influence on aromatic amine solubilityPublication . Morais, Ana Rita C.; Lopes, André; Bogel-Lukasik, Ewa; Lukasik, Rafal M.he mutual solubility of aniline and a series of imidazolium based ionic liquids with bis(trifluoromethylsulfonyl)amide, chloride, dicyanamide, tetrafluoroborate, and hexafluorophospate anions were studied. The produced results show the potential in the new solvent systems which can be used in amine chemistry. The liquid–liquid equilibrium (LLE) and solid–liquid equilibrium (SLE) measurements were performed using a dynamic (synthetic) method. The mutual solubility of aniline in bis(trifluoromethylsulfonyl)amide and hexafluorophosphate ionic liquids was complete in the examined range of temperatures. The solubility of remaining studied ionic liquids decreases with the decrease of Kamlet–Taft basicity of ionic liquid anion. In other words, the solubility was the lowest for a chloride ionic liquid and increases for dicyanamide and for tetrafluoroborate ionic liquids. Additionally, the increase of the alkyl chain length of the IL cation effects negatively the solubility of aniline in the investigated ionic liquids.
- A new outlook on solubility of carbohydrates and sugar alcohols in ionic liquidsPublication . Conceição, Lucinda J. A.; Bogel-Lukasik, Ewa; Lukasik, Rafal M.Ionic liquids are innovative media characterised by an easy tunability of physical and chemical properties with the potential for broad usefulness in a wide spectrum of chemical applications. One example of such an application is a complex biorefinery concept leading to the exploitation of the biomass for the production of energy (heat, power, fuel) and value added products. Until now ionic liquids have proven their feasibility to dissolve selectively biomass as a whole as well as individual carbohydrates. This work demonstrates the solubility of carbohydrates and value added products—sugar alcohols—which can be obtained from biomass through the biorefinery concept. The novelty of our investigation includes either solubility studies of sugar alcohols or an involvement of unexplored ionic liquids yet. In this research, a variety of ionic liquids constituted by imidazolium, pyridinium and phosphonium cations was applied. Furthermore, anions of ionic liquids, attractive from a point of view of a broad application, such as: 2-(2-methoxyethoxy)ethylsulfate, hydrogen sulfate, thiocyanate, tricyanomethanide, tetrachloroferrate, perfluorobutane sulfonate and tosylate were investigated. In this work, it was discovered that solubility of carbohydrates and sugar alcohols can exceed even 75 wt% at an easily achievable temperature depending on the choice of the ionic liquid.
- Pre-treatment of lignocellulosic biomass using ionic liquids: wheat straw fractionationPublication . Lopes, André; João, Karen; Rubik, Djonatam; Bogel-Lukasik, Ewa; Duarte, Luís C.; Andreaus, Jurgen; Lukasik, Rafal M.This work is devoted to study pre-treatment methodologies of wheat straw with 1-ethyl-3-methylimidazolium acetate ([emim][CH3COO]) and subsequent fractionation to cellulose, hemicellulose and lignin. The method developed and described here allows the separation into high purity carbohydrate and lignin fractions and permits an efficient IL recovery. A versatility of the established method was confirmed by the IL reuse. The fractionation of completely dissolved biomass led to cellulose-rich and hemicellulose-rich fractions. A high purity lignin was also achieved. To verify the potential further applicability of the obtained carbohydrate-rich fractions, and to evaluate the pre-treatment efficiency, the cellulose fraction resulting from the treatment with [emim][CH3COO] was subjected to enzymatic hydrolysis. Results showed a very high digestibility of the cellulose samples and confirmed a high glucose yield for the optimized pre-treatment methodology.
- Pretreatment and fractionation of wheat straw using various ionic liquidsPublication . Lopes, André; João, Karen; Bogel-Lukasik, Ewa; Roseiro, Luisa B.; Lukasik, Rafal M.Pretreatment of lignocellulosic biomass with ionic liquids (ILs) is a promising and challenging process for an alternative method of biomass processing. The present work emphasizes the examination of wheat straw pretreatment using ILs, namely, 1-butyl-3-methylimidazolium hydrogensulfate ([bmim][HSO4]), 1-butyl-3-methylimidazolium thiocyanate ([bmim]-[SCN]), and 1-butyl-3-methylimidazolium dicyanamide ([bmim][N(CN)2]). Only [bmim][HSO4] was found to achieve a macroscopic complete dissolution of wheat straw during pretreatment. The fractionation process demonstrated to be dependent on the IL used. Using [bmim][SCN], a high-purity lignin-rich material was obtained. In contrast, [bmim][N(CN)2] was a good solvent to produce high-purity carbohydrate-rich fractions. When [bmim][HSO4] was used, a different behavior was observed, exhibiting similarities to an acid hydrolysis pretreatment, and no hemicellulose-rich material was recovered during fractionation. A capillary electrophoresis (CE) technique allowed for a better understanding of this phenomenon. Hydrolysis of carbohydrates was confirmed, although an extended degradation of monosaccharides to furfural and hydroxymethylfurfural (HMF) was observed.
- Solubility of pharmaceutical compounds in ionic liquidsPublication . Santos, Ana Duarte dos; Morais, Ana Rita C.; Melo, Catarina I.; Lukasik, Rafal M.; Bogel-Lukasik, EwaThe solubility of N-acetyl-l-cysteine, coumarin and 4-hydroxycoumarin in alternative solvents was studied in this work. The solid–liquid equilibrium (SLE) measurements have been performed using a dynamic(synthetic) method. Melting points and enthalpies of fusion of the pharmaceutical compounds were acquired using a differential scanning calorimetry (DSC). The solubility of N-acetyl-l-cysteine and 4-hydroxycoumarin in trifluoromethanesulfonate ionic liquids was found to be significantly higher thanin the studied bis(trifluoromethylsulfonyl)amide ionic liquids while coumarin exhibited the oppositebehaviour.The solid–liquid phase equilibria were described using the six different correlation equations whichrevealed a good description with an acceptable standard deviation temperature range.Moreover, the solubility data were used to calculate the 1-octanol/water partition coefficients of thestudied drugs. Coumarin has a high partition coefficient, which is considered to be favourable for a rapidabsorption of compounds once they are in an aqueous solution. N-acetyl-l-cysteine showed oppositeresults for the system with 1-octanol/water.