Investigation of Vapor – Liquid Equilibrium, Volumetric, Compressibility and Transport Properties of Some Aqueous Saccharides in Presence of Ionic Liquids

Lignocellulosic biomass is nontoxic and biodegradable source of saccharides that can be used for the production of fuels and chemicals [1, 2]. However due to their complex structure and low solubility in conventional solvents, the effective conversion of these compounds faces with some challanges [3]. To solve these problems, a new type of solvent referred to ionic liquid has been proposed to use in biomass pretreatment process [4, 5]. In this work the salt effect resulted by addition of ionic liquids to aqueous saccharide solutions is investigated. To achieve this goal, systematic studies have been made on ternary {saccharide + ionic liquid + water} system using the vapor-liquid equilibrium, density, speed of sound and viscosity data. To investigate ionic liquid-water and saccharide-water interactions, vapor pressure depression, osmotic and activity coefficient data for the ionic liquids and saccharides in the binary solutions are used. To study saccharide-ionic liquid interactions in ternary solutions, the activity coefficient of saccharides in presence of ionic liquids, transfer Gibbs energies, pair and triplet interaction parameters, salting constants, standard partial molar volume (VΦ0 ), partial molar isentropic compressibility (Φ0 ), hydration number (nH) , and viscosity B-coefficient (B) are used. The variety of ionic liquids based on imidazolium and pyridinium have been studied. In this article, the effect of stereochemistry of sugar, cation (imidazolium or pyridinium), chain length and anion of ionic liquids on saccharide-ionic liquid interactions have been discussed.