42 documents found, page 1 of 5
Imidazolium chloride ionic liquid mixtures as separating agents: fuel processin...
Vilas-Boas, Sérgio M.; Martins, Mónia A.R.; Tentor, Fabio Ribeiro; Teixeira, Gabriel; Sgorlon, Juliana; Coutinho, João A.P.; Ferreira, OlgaRelevant chemical separations for the petrochemical and chemical industries include the removal of aromatic hydrocarbons from aliphatics, the desulfurization and denitrification of fuels, and the separation of azeotropic mixtures containing alkanols. In an attempt to contribute to the development of novel technologies, the potentialities of imidazolium chloride ionic liquid (IL) mixtures as separation agents we...
Insights into the chloride versus bromide effecton the formation of urea quater...
Martins, Mónia A.R.; Abranches, Dinis O.; Silva, Liliana P.; Pinho, Simão; Coutinho, João A.P.The intermolecular interactions of urea and quaternary ammonium salts relevant to their thermodynamic nonideality were here investigated by measuring the solid-liquid equilibria of their binary mixtures. The experimental data revealed that the anion transfer between the quaternary ammonium salt and urea increases with increasing alkyl chain lengths, leading to negative deviations from ideality in the urea-rich ...
Extensive characterization of choline chloride and its solid–liquid equilibrium...
Ferreira, Ana I.M.C. Lobo; Vilas-Boas, Sérgio M.; Silva, Rodrigo M.A.; Martins, Mónia A.R.; Abranches, Dinis O.; Paz, Filipe A. Almeida; Ferreira, OlgaThe importance of choline chloride (ChCl) is recognized due to its widespread use in the formulation of deep eutectic solvents. The controlled addition of water in deep eutectic solvents has been proposed to overcome some of the major drawbacks of these solvents, namely their high hygroscopicities and viscosities. Recently, aqueous solutions of ChCl at specific mole ratios have been presented as a novel, low vi...
Ionic liquids as entrainers for terpenes fractionation and other relevant separ...
Vilas-Boas, Sérgio M.; Teixeira, Gabriel; Rosini, Sabrina Barbosa; Martins, Mónia A.R.; Gaschi, Priscilla S.; Coutinho, João A.P.; Ferreira, OlgaThis work discusses the potential of two phosphonium-based ionic liquids (ILs), [P6,6,6,14]Cl and [P6,6,6,14][(C8H17)2PO2], and one methylimidazolium-based IL, [C4mim][OAc], as entrainers in the fractionation of terpene mixtures, in the desulfurization and denitrification of fuel oils, and in the separation of aromatics from aliphatic hydrocarbons. To this aim, the activity coefficients at infinite dilution of ...
The impact of oligomeric anions on the speciation of protic ionic liquids
Martins, Mónia A.R.; Carvalho, Pedro J.; Santos, Luís M.N.B.F.; Pinho, Simão; Coutinho, João A.P.The synthesis of protic ionic liquids based in carboxylate anions, too often admitted as being straightforward, is actually challenging and must be carefully addressed. This review discusses the importance of oligomeric anions, in particular those based on carboxylates, in the behavior and nature of protic ionic liquids. There is strong evidence in the literature that the synthesis, and subsequent purification,...
Solid-liquid phase behavior of eutectic solvents containing sugar alcohols
Silva, Liliana P.; Martins, Mónia A.R.; Abranches, Dinis O.; Pinho, Simão; Coutinho, João A.P.Mixtures of carbohydrates are often reported in the literature as deep eutectic solvents yet, in most cases, their solid–liquid phase diagrams are poorly characterized and no evidence is available to validate this classification. In this work, the phase diagrams of the binary systems composed of the sugar alcohols mannitol or maltitol and meso-erythritol, xylitol, or sorbitol, were experimentally determined. Th...
Infinite dilution activity coefficients in the smectic and isotropic phases of ...
Martins, Mónia A.R.; Vilas-Boas, Sérgio M.; Cordova, Isabella Weber; Carvalho, Pedro J.; Domańska, Urszula; Ferreira, Olga; Coutinho, João A.P.Inverse gas chromatography was used to obtain the activity coefficients at infinite dilution (γ13∞) of several organic solutes and water in the thermotropic ionic liquid crystal phases of both [C12mim][BF4] and [C14mim][BF4] and their isotropic phases. In the smectic to isotropic transition, a change in the linear representation of the natural logarithm of γ13∞ with the reciprocal temperature was observed for [...
The role of ionic vs. non-ionic excipients in APIs-based eutectic systems
Martins, Mónia A.R.; Silva, Liliana P.; Jorge, Patrícia S.; Abranches, Dinis O.; Pinho, Simão; Coutinho, João A.P.Aiming to contribute to drug pre-formulation, new eutectic mixtures were developed. Thymol, coumarin, or quaternary ammonium chlorides as excipients, were combined with the active pharmaceutical ingredients (APIs) acetylsalicylic acid, acetaminophen, ibuprofen, ketoprofen, or lidocaine. Their solid-liquid equilibrium (SLE) binary phase diagrams were measured to study eventual phase separation between the compou...
The impact of oligomeric anions on the speciation of protic ionic liquids
Martins, Mónia A.R.; Carvalho, Pedro J.; Santos, Luís M.N.B.F.; Pinho, Simão P.; Coutinho, João A.P.The synthesis of protic ionic liquids based in carboxylate anions, too often admitted as being straightforward, is actually challenging and must be carefully addressed. This review discusses the importance of oligomeric anions, in particular those based on carboxylates, in the behavior and nature of protic ionic liquids. There is strong evidence in the literature that the synthesis, and subsequent purification,...
Understanding the formation of deep eutectic solvents: betaine as a universal h...
Abranches, Dinis O.; Silva, Liliana P.; Martins, Mónia A.R.; Pinho, Simão; Coutinho, João A.P.© 2020 Wiley-VCH GmbH The mechanism of formation of betaine-based deep eutectic solvents (DES) is presented for the first time. Due to its polarity unbalance, it was found that betaine displays strong negative deviations from ideality when mixed with a variety of different organic substances. These results pave the way for a comprehensive design of novel deep eutectic solvents. A connection to biologically rele...