Density of Mixtures Containing Sugars and Ionic Liquids: Experimental Data and PC-SAFT Modeling

Abstract

The potential use of ionic liquids (ILs) for biomass and carbohydrate processing has been discovered in the past decade. Many advantages have been pointed out in their application for biorefining purposes. The phase equilibria and volumetric properties of mixtures containing ILs and biomass-derived compounds such as sugars or sugar alcohols are relevant for process design. In this work, the density, at atmospheric pressure, of binary mixtures containing sugars (glucose and fructose) or sugar alcohols (xylitol and sorbitol) and ionic liquids (1-ethyl-3-methylimidazolium ethylsulfate and Aliquat336) is presented within large temperature (278 K to 343 K) and composition ranges (up to sugar or sugar alcohol mass fraction of 0.30). The density data followed a bilinear trend with respect to temperature and composition. The data were therefore represented using planar regression with a very good accuracy, average relative deviation (ARD) <0.1 % in most of the cases. The perturbed-chain statistical association fluid theory (PC-SAFT) equation of state was applied to model solutions containing ILs. The pure component parameters for Aliquat336 were fitted to pure-IL density data. Appluing temperature-dependent K-ij parameters, PC SAFT allowed satisfactory modeling of the measured density data and literature solubility data of sugars and sugar alcohols in Aliquat336.