Measurement and PC-SAFT modeling of the water activity for aqueous solutions of D-mannose in some deep eutectic solvents

Abstract

The knowledge of thermodynamic properties for D-mannose has of great specific importance in viewpoint of biological behavior and understanding of solute-solvent interactions. In this work, vapor- liquid equilibrium data of ternary systems containing some deep eutectic solvents (DESs) based on choline chloride (ChCl/Urea - ChCl/Ethylene Glycol - ChCl/Glycerol) as co-solvent, D-mannose and water were measured using by isopiestic method at 298.15 K. The PC-SAFT EOS was used for predicting water activity and vapor pressure of water in the solutions. The binary interaction parameter kij between DES and D-mannose were determined from the average fitting parameter interaction of the binary DES-water and D-mannose-water systems. The calculated vapor pressure data with compared to excremental data show AAD% less than 0.09. The ternary (ChCl/Urea + D-mannose + H2O) system has the lowest amount of ARD. Also, the calculated Gibbs free energies of transfer ΔGtri of D-mannose from water to aqueous solution of DES supply favorable interactions between D-mannose with DESs and salting-in effect. Also, the glycerol based DES has stronger interactions rather than the others due to strong hydrogen bonding. Generally, the results indicate the high performance of PC-SAFT to calculate of vapor pressure of water and water activity in the ternary studied systems.