Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

Activity coefficients at infinite dilution, Ai , of different solutes (alkanes, alkenes, and alkylbenzenes as well as of the linear C1-C6 alcohols) in the paramagnetic ionic liquid 1-butyl-3-methylimidazolium tetrabromidocobaltate( II), (C4MIm)2[CoBr4], have been determined by gas chromatography using the ionic liquid as the stationary phase. The measurements were carried out at different temperatures between (308 and 413) K. From the temperature dependence of the limiting activity coefficients, partial molar excess enthalpies at infinite dilution Hi E, of the solutes in the ionic liquid have been derived. Values of Ai of solutes in the paramagnetic ionic liquid (C4MIm)2[CoBr4] have been compared at 298 K with results of Ai for ionic liquids containing the 1-butyl-3-methylimidazolium cation and different nonmagnetic anions. No significant effects caused by the paramagnetic anion have been observed. Furthermore, the single-crystal X-ray structure has been determined. It crystallizes monoclinic (C2/c), a ) 16.7027(7), b ) 10.3163(4), c ) 15.4136(7) A, and ) 114.246(2) . The structure consists of isolated tetrahedral [CoBr4]2- complex anions and 1-butyl-3- methylimidazolium cations.