2294-38-4Relevant articles and documents
Thermal behaviour of mixtures of 1-alkylpyridinium halides with and without a common ion
Stolarska, Olga,Soto, Ana,Rodríguez, Héctor,Smiglak, Marcin
, p. 781 - 790 (2018)
The thermal behaviour of mixtures of 1-alkylpyridinium halide salts, comprising either three or four different types of ions, was investigated in order to develop a better understanding of this class of multi-ion systems. A total of six systems was examined, derived from all possible binary combinations of the following four salts: 1-butylpyridinium bromide ([C4Py]Br), 1-butylpyridinium chloride ([C4Py]Cl), 1-ethylpyridinium bromide ([C2Py]Br), and 1-ethylpyridinium chloride ([C2Py]Cl). The systems constituted by two of these salts with a common anion and therefore differing only in the length of the alkyl substituent of the cation (namely [C2Py]Br + [C4Py]Br and [C2Py]Cl + [C4Py]Cl) displayed a eutectic behaviour, with the eutectic compositions qualifying as ionic liquids (melting temperature below 373 K). In contrast, the systems having in common the cation and differing in the halide anion (namely [C2Py]Br + [C2Py]Cl and [C4Py]Br + [C4Py]Cl) showed the formation of solid solutions. The two remaining combinations ([C2Py]Br + [C4Py]Cl and [C2Py]Cl + [C4Py]Br), involving four different types of ions, were also found to display a eutectic behaviour. The melting point depressions of the eutectic points with respect to the parent salts were of about 30–70 K. This was also the liquid range increase achieved with the eutectic compositions, since their thermal stability was nearly the same as the similar thermal stabilities of their parent salts. All six binary combinations of the four 1-alkylpyridinium halides were also interpreted as subsystems of the general 4-ion system [C2Py]x[C4Py]1-xClyBr1-y (where x is the cationic fraction of [C2Py]+ and y is the anionic fraction of Cl?), and an analysis of the melting temperature throughout the domain of this system was carried out.
Does alkyl chain length really matter? Structure-property relationships in thermochemistry of ionic liquids
Verevkin, Sergey P.,Zaitsau, Dzmitry H.,Emel'Yanenko, Vladimir N.,Ralys, Ricardas V.,Yermalayeu, Andrei V.,Schick, Christoph
, p. 84 - 95 (2013/07/28)
DSC was used for determination of reaction enthalpies of synthesis of ionic liquids [Cnmim][Cl]. A combination of DSC with quantum chemical calculations presents an indirect way to study thermodynamics of ionic liquids. The indirect procedure for vaporization enthalpy was validated with the direct experimental measurements by using thermogravimetry. First-principles calculations of the enthalpy of formation in the gaseous phase have been performed for the ionic species using the CBS-QB3 and G3 (MP2) theory. Experimental DSC data for homologous series of alkyl substituted imidazolium, pyridinium, and pyrrolidinium based ionic liquids with anions [Cl] and [Br] were collected from the literature. We have shown that enthalpies of formation, enthalpies of vaporization, and lattice potential energies are linearly dependant on the alkyl chain length. The thermochemical properties of ILs generally obey the group additivity rules and the values of the additivity parameters for enthalpies of formation and vaporization seem to be very close to those for molecular compounds.
Method for the preparation of 1-alkyl pyridinium chlorides
-
, (2008/06/13)
A method for preparing alkyl pyridinium chlorides by effecting a direct reaction between the corresponding alkyl chloride and pyridine.
