Maciej Zawadzki

Perturbed-Chain SAFT as a Versatile Tool for Thermodynamic Modeling of Binary Mixtures Containing Isoquinolinium Ionic Liquids

This contribution reports a recapitulation of our experimental and modeling study on thermodynamic behavior of binary systems containing N-alkylisoquinolinium ionic liquids (ILs) based on bis(trifluoromethylsulfonyl)imide anion, [CniQuin][NTf2] (n = 4,6,8). In particular, we report isothermal vapor-liquid equilibrium (VLE) phase diagrams and molar excess enthalpies of mixing (H(E)) for binary mixtures of [C8iQuin][NTf2] IL with various organic solutes including benzene, toluene, thiophene, pyridine, and butan-1-ol. The measured VLE data represented simple homozeotropic behavior with either negative or positive deviations from ideality, depending on polarity of the solute, temperature, and mole fraction of IL. In turn, the obtained data on H(E) were negative and positive for the mixtures containing aromatic hydrocarbons or thiophene and butan-1-ol, respectively, in the whole range of ILs concentration. All of the measured and some previously published data regarding phase behavior of [C8iQuin][NTf2] IL were analyzed and successfully described in terms of perturbed-chain statistical associating fluid theory (PC-SAFT). The methodology used in this work was described by us previously. In general, the proposed modeling results in VLE diagrams, which are in excellent agreement with experimental data. In the case of H(E), the results obtained are good as well but not so satisfactory such as those for VLE. Nevertheless, they seem to be very promising if one take into account the simplicity of the utilized molecular model against significant complexity of IL-based systems. Thus, we concluded that PC-SAFT equation of state can be viewed as a powerful and robust tool for modeling of systems involving ILs.

Phase equilibria study of the binary systems (N-hexylisoquinolinium thiocyanate ionic liquid + organic solvent or water).

Liquid-liquid phase equilibria (LLE) of binary mixtures containing a room-temperature ionic liquid N-hexylisoquinolinium thiocyanate, [HiQuin][SCN] with an aliphatic hydrocarbon (n-hexane, n-heptane), aromatic hydrocarbon (benzene, toluene, ethylbenzene, n-propylbenzene), cyclohexane, thiophene, water, and 1-alcohol (1-ethanol, 1-butanol, 1-hexanol, 1-octanol, 1-decanol) have been determined using a dynamic method from room temperature to the boiling-point of the solvent at ambient pressure. N-hexylisoquinolinium thiocyanate, [HiQuin][SCN] has been synthesized from N-hexyl-isoquinolinium bromide as a substrate. Specific basic characterization of the new compound including NMR spectra, elementary analysis, and water content have been done. The density and viscosity of pure ionic liquid were determined over a wide temperature range from 298.15 to 348.15 K. The mutual immiscibility with an upper critical solution temperature (UCST) for the binary systems {IL + aliphatic hydrocarbon, cyclohexane, or water} was detected. In the systems of {IL + aromatic hydrocarbon or thiophene} an immiscibility gap with a lower critical solution temperature (LCST) was observed. Complete miscibility in the liquid phase, over a whole range of ionic liquid mole fraction, was observed for the binary mixtures containing IL and an 1-alcohol. For the tested binary systems with immiscibility gap {IL + aliphatic hydrocarbon, aromatic hydrocarbon, cyclohexane, thiophene, or water}, the parameters of the LLE correlation have been derived using the NRTL equation. The basic thermal properties of the pure IL, that is, the glass-transition temperature as well as the heat capacity at the glass-transition temperature, have been measured using a differential scanning microcalorimetry technique (DSC). Decomposition of the IL was detected by simultaneous thermogravimetric/differential thermal analysis (TG/DTA) experiments.

Phase equilibria study of {N-hexylisoquinolinium bis{(trifluoromethyl)sulfonyl}imide + aromatic hydrocarbons or an alcohol} binary systems.

Isoquinolinium ionic liquid (IL) has been synthesized from N-hexylisoquinolinium bromide as a substrate. Specific basic characterization of the synthesized compound is included, which includes NMR spectra, elementary analysis, and water content. The basic thermal properties of the pure IL, that is, melting and solid-solid transition temperatures, as well as the enthalpy of fusion, or solid-solid transition have been measured using a differential scanning microcalorimetry technique. The density and viscosity as a function of temperature have been measured for the pure IL at temperatures higher than the melting temperature and were extrapolated to T = 298.15 K. The temperature-composition phase diagrams of 8 binary mixtures composed of the IL N-hexylisoquinolinium bis{(trifluoromethyl)sulfonyl}imide, ([HiQuin][NTf(2)]) and an aromatic hydrocarbon (benzene, or toluene, or ethylbenzene, n-propylbenzene) or an alcohol (1-butanol, or 1-hexanol, or 1-octanol, or 1-decanol) have been determined from ambient temperature to the boiling-point temperature of the solvent at ambient pressure. A dynamic method was used over a broad range of mole fractions and temperatures from 270 to 330 K. For the binary systems, the eutectic diagrams were observed with immiscibility in the liquid phase with an upper critical solution temperature (UCST). In the case of the mixture {IL + benzene, or alkylbenzene} the eutectic systems with mutual immiscibility in the liquid phase with very high UCSTs were observed. These points were not detectable with our method and were observed at low IL mole fraction. For mixtures with alcohols, it was observed that with an increasing chain length of an alcohol, the solubility decreases and the UCST increases. The coexistence curves corresponding to liquid-liquid phase equilibrium boundaries and the solid-liquid phase equilibrium has been correlated using the well-known nonrandom two-liquid (NRTL) model.

Recovery of an antidepressant from pharmaceutical wastes using ionic liquid-based aqueous biphasic systems

This study is aimed at developing a sustainable process for the recovery of valuable drugs from pharmaceutical wastes using ionic liquid (IL)-based aqueous biphasic systems (ABS). Because in pharmaceutical wastes, excipients represent the major contaminants, the search for selective routes for their elimination is of primordial relevance and for that purpose IL-based ABS were evaluated. The effects of different process parameters, namely the IL nature, pH and mixture composition used in the extraction system, were studied and the process was optimized to maximize the extraction of the antidepressant from pharmaceutical wastes. Moreover, the maximum amount of amitriptyline able to be processed using such systems was assessed. The set of ABS investigated herein revealed a high extraction performance, as indicated by the outstanding logarithmic functions of the amitriptilyne partition coefficients ranging from 2.41 ± 0.05 to >2.5 and extraction efficiencies between 66% ± 1% and 100%. The best ABS and conditions were considered in the development of an integrated multi-step purification process. The process here proposed comprises three main stages as follows: the solid–liquid extraction of the antidepressant from ADT 25 pills, its purification using the optimal IL-based ABS and the antidepressant isolation by precipitation with anti-solvent. After the removal of most water insoluble excipients in the first step, with the selected IL-based ABS, it was possible to further eliminate water soluble contaminants. A high capability of extraction and purification, leading to the selective separation of amitriptyline hydrochloride from the main contaminants contained in solid pharmaceutical wastes was achieved. Finally, the isolation of the amitriptilyne in a pure state was successfully accomplished through precipitation with the anti-solvent.

Extraction of 2-Phenylethanol (PEA) from Aqueous Solution Using Ionic Liquids: Synthesis, Phase Equilibrium Investigation, Selectivity in Separation, and Thermodynamic Models

This study assessed the effect of ionic liquids (ILs) on extraction of 2-phenylethanol (PEA) from aqueous phase. It consists the synthesis of four new ILs, their physicochemical properties, and experimental solubility measurements in water as well as liquid-liquid phase equilibrium in ternary systems. ILs are an important new media for imaging and sensing applications because of their solvation property, thermal stability, and negligible vapor pressure. However, complex procedures and nonmiscibility with water are often required in PEA extraction. Herein, a facile and general strategy using four ILs as extraction media including the synthesis of new bis(fluorosulfonyl)imide-based ILs, 1-hexyl-methylmorpholinium bis(fluorosulfonyl)imide, [HMMOR][FSI], N-octylisoquinolinium bis(fluorosulfonyl)imide, [OiQuin][FSI], 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide, [BMPYR][FSI], and N-triethyl-N-octylammonium bis(fluorosulfonyl)imide, [N2228][FSI], were investigated. The thermal properties, density, viscosity, and surface tension of new ILs were measured. Calorimetric measurements (DSC) were used to determine the melting point and the enthalpy of melting as well as the glass transition temperature and heat capacity at glass transition of the ILs. The phase equilibrium in binary systems (IL + PEA, or water) and in ternary systems {IL (1) + PEA (2) + water (3)} at temperature T = 308.15 K and ambient pressure are reported. All systems present liquid-liquid equilibrium with the upper critical solution temperature (UCST). All ILs revealed complete miscibility with PEA. In all ternary systems immiscibility gap was observed, which classified measured systems as Treybals type II. The two partially miscible binaries (IL + water) and (PEA + water) exist in these systems. The discussion contains the specific selectivity and the solute distribution ratio of separation for the used ILs. The commonly used NRTL model was used for the correlation of the experimental binary and ternary systems with acceptable root-mean-square deviation. The prediction of binary and ternary compositions was provided with acceptable deviations using COSMO RS. The data of ternary LLE show the possible use of [HMMOR][FSI] as a good entrainer for the separation of PEA from water using solvent extraction.

Heat Capacity, Excess Molar Volumes and Viscosity Deviation of Binary Systems of N-octylisoquinolinium bis{(trifluoromethyl)sulfonyl}imide Ionic Liquid

Abstract Heat capacities were determined for two binary systems {N-octylisoquinolinium bis{(trifluoromethyl)sulfonyl} imide, ([C8iQuin][NTf2]) + benzene, or butan-1-ol} from (288.15 to 388.15) K. Density and viscosity were determined for four binary mixtures containing {[C8iQuin][NTf2]) + benzene, or toluene, or thiophene or pyridine} at six temperatures (298.15, 308.15, 318.15, 328.15, 338.15 and 348.15) K, ambient pressure, and covering the entire composition range. The influence of temperature and composition was discussed. As usually the heat capacity increases with an increase of the ionic liquid concentration. The molar heat capacities, densities and viscosities were correlated with suitable equations. The excess molar heat capacities, Δ Cp, the excess molar volumes, VmE and dynamic viscosity deviations, Δη were described by the Redlich–Kister polynomial expansion. The Δ Cp was negative for benzene and S-shaped for butan-1-ol, the VmE and Δη were low and negative. From the experimental values, the volume expansivity and the excess volume expansivity was calculated. The obtained results indicate that ionic liquid interactions with aromatic hydrocarbons are strong dependent on the packing effects and π–π interactions.

Studying of drug solubility in water and alcohols using drug-ammonium ionic liquid-compounds

ABSTRACT Synthesis of three mefenamic acid (MEF) derivatives ‐ ionic liquid compounds composed of MEF in an anionic form and ammonium cation (choline, MEF1), or {di(2‐hydroxyethyl)dimethyl ammonium (MEF2)}, or {tri(2‐hydroxyethyl)methyl ammonium compound (MEF3)} is presented. The basic thermal properties of pure compounds i.e. fusion temperatures, and the enthalpy of fusion of these compounds have been measured with differential scanning microcalorimetry technique (DSC). Molar volumes have been calculated with the Barton group contribution method. The solubilities of MEF1, MEF2 and MEF3 using the dynamic method were measured at constant pH in a range of temperature from (290 to 370) K in three solvents: water, ethanol and 1‐octanol. The experimental solubility data have been correlated by means of three commonly known GE equations: the Wilson, NRTL and UNIQUAC with the assumption that the systems studied here present simple eutectic behaviour. The activity coefficients of pharmaceuticals at saturated solutions in each binary mixture were calculated from the experimental data. The formation of MEF‐ionic liquid compounds greatly increases the solubility in water in comparison with pure MEF or complexes with 2‐hydroxypropyl‐&bgr;‐cyclodextrin. The development of these compounds formulations will assist in medication taking into account oral solid or gel medicines. Graphical abstract Figure. No Caption available.