Investigation of physicochemical properties of NADES based on choline chloride and ascorbic acid and its binary solutions with DMSO from (298.15 to 353.15) K

Abstract

There is growing environmental concern created by large scale use of organic solvents. The quest to replace them with benign solvents led to the synthesis of ionic liquids (ILs) and later deep eutectic solvents (DES) as green replacements for volatile organic compounds. Although ILs and DES have similar physicochemical properties, DES are preferred because their toxicity is low compared to ILs and because they are easily synthesized from inexpensive and readily available precursors. Among DES, natural deep eutectic solvents (NADES) are gaining more attention due to their several naturally abundant precursors. Due to higher benefits of NADES, it is desirable to explore their physicochemical properties. The present study investigates the physicochemical properties of ChCl/AA NADES and its mixtures with dimethyl sulfoxide (DMSO). The effect of composition and temperature in the range (298.15–353.15) K on these properties is also investigated. The ChCl/AA NADES and DMSO mixtures demonstrate positive excess molar volume, with maximum centered close to x1=0.7 (x1 is mole fraction of ChCl/AA NADES) which became more prominent with increasing temperature. In contrast, a relatively broad minimum is observed for excess molar viscosity and the obtained information is further used to explain the molecular interactions in the NADES - DMSO system. The temperature dependence of viscosity and electrical conductivity is explained satisfactorily using Vogel-Fulcher- Tammann (VFT) equation.