Collect. Czech. Chem. Commun. 2008, 73, 657-664

Solid-Liquid Equilibrium in the Systems with an Ionic Liquid

Zuzana Sedláková, Hélène Sauton, Vladimír Hynek and Ivona Malijevská*

Department of Physical Chemistry, Institute of Chemical Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic


An active interest in ionic liquids has grown over the last years. This relatively new class of solvents appears to be potentially useful as a "greener" alternative to volatile organic compounds. This work was aimed at studying the effect of addition of the ionic liquid 1-butyl-3-methylimidazolium chloride to two systems (acetic acid (1)-formamide (2) and propionic acid (1)-formamide (2)) on formation of a compound in the solid phase. In previous work, the presence of a solid compound with a formula (CH3COOH)2·HCONH2 was investigated in the binary system acetic acid (1)-formamide (2) and a stable solid compound with a different formula CH3CH2COOH·(HCONH2)2 was found in the binary system propionic acid (1)-formamide (2). In both cases the compound formation is attributed to a strong cross-association (O···H···N). Solid-liquid equilibrium of the systems measured in this work was determined from time-temperature warming curves. In both measured ternary systems with a small addition of the ionic liquid 1-butyl-3-methylimidazolium chloride (i.e. the systems acetic acid (1)-formamide (2)-1-butyl-3-methylimidazolium chloride (3) and propionic acid (1)-formamide (2)-1-butyl-3-methylimidazolium chloride (3)) the above mentioned stable solid compounds are formed and the corresponding melting temperature of these compounds decreased. Dissociation parameters were modelled thermodynamically for solid adducts.

Keywords: Experimental data; Acetic acid; Formamide; Propionic acid; Solid-liquid equilibrium; 1-Butyl-3-methylimidazolium chloride.

References: 10 live references.