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The solubility of an antitubercular drug in alternative solvents can offer a potential application in pharmaceutical processing. Solid−liquid equilibrium (SLE) measurements have been made using a dynamic (synthetic) method. The melting point, the enthalpy of fusion, temperature of the solid−solid phase transition, and corresponding enthalpy of pyrazine-2-carboxamide were obtained using differential scanning calorimetry (DSC). The solubility of pyrazine-2carboxamide in bis(trifluoromethylsulfonyl)amide ionic liquids is at least 1 order of magnitude lower than that in the studied trifluoromethanesulfonate ionic liquid. 1-Decyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid was found to be the best solvent for a carboxamide drug. 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. Nonvolatile ionic liquids, due to their safer aspects, can compete with other potentially flammable chemicals that are routinely used in the pharmaceutical development, given the data presented for the pyrazine derivative. Bis(trifluoromethylsulfonyl)amide and trifluoromethanesulfonate based ionic liquids showed sufficient solubilities toward a drug; thus, it makes them suitable for the future pharmaceutical processing.

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The efficient transformation of carbon dioxide into fuels can be an excellent alternative to sequestration. In this work, we describe CO2 hydrogenation to methane in imidazolium-based ionic liquid media, using ruthenium nanoparticles prepared in situ as catalyst. The best yield of methane (69 %) was achieved using 0.24 mol % ruthenium catalyst (in [omim][NTf2 ], 1-octyl-3-methylimidazolium bistrifluoromethanesulfonylimide, at 40 bar of hydrogen pressure plus 40 bar of CO2 pressure, and at 150 °C.

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The evolution of technology is directed to reduce industrial waste from chemical processes to zero. In the past decade interest in ionic liquids (ILs) has grown, and they have been recognized as potential substitutes for volatile organic solvents used in certain chemical processes, including those in the pharmaceutical industry. Following this increasing interest and because ILs can have a great potential for the pharmaceutical industry, we tested the solubility of two antitubercular medicines, pyrazinecarboxamide and isoniazid, in imidazolium ionic liquids, namely [C4mim]­[BF4], [C4mim]­[PF6], [C4mim]­[OTf], and [C8mim]­[OTf], in the range of 279.98 to 417.05 K. Both drugs exhibited an improved solubility in [C4mim]­[BF4] than in the other studied ILs. The solutes had an enhanced solubility in more hydrophilic ILs, such as [C4mim]­[BF4] and [C4mim]­[PF6]. The solubility decreased in ILs containing the hydrophobic anion trifluoromethanesulfonate and with the increasing alkyl chain length in the cation. The solid–liquid phase equilibria of all investigated systems were described using six different correlation equations. The satisfactory results which revealed a good description with an acceptable standard deviation temperature range were collected for isoniazid or pyrazinecarboxamide in [C4mim]­[PF6], [C4mim]­[OTf] and [C8mim]­[OTf]. Comparison to solubility in NTf2 and [C10mim]­[OTf] was provided.

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