Unraveling the effect of choline-based choline based ionic liquids on the physicochemical properties and taste behavior of D( +)-glucose in aqueous solutions

To elucidate the mechanism by which choline-based ionic liquids potentially can enhance the sugar conversion to bioethanol, this work was conducted to study the thermodynamic behavior of D( +)-glucose in aqueous solutions of choline-based ionic liquids, choline salicylate [Ch][Sal], choline formate [Ch][For], and choline acetate [Ch][Ace]. This study involved measuring density, speed of sound, viscosity, and electrical conductivity at various concentrations and temperatures. Analysis of the calculated parameters, including apparent molar volume, V_φ, apparent molar isentropic compressibility (κ_φ), viscosity B-coefficient, and molar conductivity (Λ) values provide deep insights into intermolecular interactions between the components of the solutions studied. The standard partial molar volume values (\(V_{\varphi }^{0}\)) of D( +)-glucose, show stronger interactions between D( +)-glucose and the [Ch][Sal]. The computed transfer volume values (\(\Delta_{tr} V_{\varphi }^{0}\)), with the help of co-sphere overlap model confirm intensified hydrophilic-hydrophilic interactions in [Ch][Sal] [(1.99 to 2.08) cm³·mol⁻¹] solutions. Hepler's constants suggest that D( +)-glucose acts as a structure-maker in the presence of choline-based ILs, especially in [Ch][Sal] solutions. Also, the DFT-COSMO calculations result in [Ch][Sal] the most favorable interactions among the other choline based ILs. Apparent specific volume (ASV), and apparent specific isentropic compressibility, (ASIC), values revealed that D( +)-glucose exhibits the taste behavior with [Ch][Sal]. The hydration number of D( +)-glucose diminishes as the temperature rises due to weakened hydrogen bonds between D( +)-glucose and water molecules. These findings suggest that [Ch][Sal] could be a promising candidate for accelerating sugar conversion to bioethanol.

Graphical Abstract