Solubility of Galactose in Aqueous Ionic Liquids, 1-Butyl-3-Methyl Imidazolium Bromide, 1-Hexyl-3-Methyl Imidazolium Bromide and 1-Butyl-3-Methylimidazolium Chloride at T = (298.15 and 308.15) K: Measurement and Modeling

Recently, ionic liquids as benign and biofriendly solvents have gained much interest indifferent fields of chemistry due to their tunable properties such as low melting point, negligiblevapor pressure, wide liquid range and high thermal and electrochemical stability [1]. Especiallythe researchers focused their attention in converting saccharides as abundant, cheap andrenewable feed stocks by ionic liquids into valuable intermediates. Ionic liquids have someadvantages in comparison to other pretreatment methods. They need a remarkably shorterprocessing time to convert pretreated biomass to fermentable sugars. In addition, the degradationof monosaccharides and formation of inhibitors is less than other methods. Furthermore,dissolution and hydrolysis reactions can be performed in relatively mild conditions [2]. Recently,researchers suggested that a mixture of ionic liquid and water instead of pure ionic liquid can beused for pretreatment of biomass [3]. In this paper the solubility of galactose in aqueous solutionscontaining ionic liquids, 1-butyl-3-methyl imidazolium bromide, [BMIm]Br, 1-hexyl-3-methylimidazolium bromide, [HMIm]Br and 1-butyl-3-methylimidazolium chloride [BMIm]Cl hasbeen measured at different ionic liquid concentrations at T = (298.15 and 308.15) K usinggravimetric method. The obtained solubility values of galactose in pure water and aqueous ionicliquid solutions were correlated successfully with the segment-based local composition modelssuch as Wilson, NRTL, modified NRTL, NRF-NRTL and UNIQUAC. In this study, the effectsof chain length and anion type of ionic liquids on solid–liquid equilibrium behavior in (galactose+ ionic liquid + water) systems have also been investigated.

Keywords:

Saccharide , Ionic Liquid , Local Composition Model , Solubility