Solid–liquid phase equilibria in binary mixtures of functionalized ionic liquids with sugar alcohols: New experimental data and modelling

• Solubility of three sugar alcohols in four ionic liquids was measured.
• An impact of cation functionalization on solubility was established.
• Apparent thermodynamic functions of dissolution were determined.
• Modelling of the studied systems with PC-SAFT equation of state was performed.

Solid–liquid equilibrium (SLE) phase diagrams of binary systems composed of dicyanamide ionic liquid and sugar alcohols (meso-erythritol, xylitol and D-sorbitol) are presented. The studied ionic liquids are based on imidazolium cations having in their structure functionalized side chains: allyl, 2-hydroxyethyl, 3-cyanopropyl, 2-chloroethyl. An impact of the terminal group is discussed in terms of molecular interactions (polarity, hydrogen bonding) between ionic liquids and sugar alcohol. Apparent thermodynamic functions of dissolution of sugar alcohols in ionic liquids were calculated with the Van’t Hoff equation. Thermodynamic modelling of the studied SLE phase diagrams with perturbed-chain statistical associating fluid theory (PC-SAFT) is presented. It is proven that accurate correlations of the considered cross-associating systems can be obtained by using relatively simple molecular schemes applied for both ionic liquids and sugar alcohols.

Figure optionsDownload as PowerPoint slide