Volumetric and transport properties of switchable-hydrophilicity solvent systems: N,N-Dimethylbutylamine, water and carbon dioxide

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Switchable-hydrophilicity solvents (SHSs) are an emerging class of solvents with switchable phase behavior. They can be used as a substitute for volatile solvents and can be removed from organic products without distillation. However, the detailed physical properties data of SHSs are still very scarce in the literature. In this work, the experimental values densities, dynamic viscosities, refractive indices as well as conductivities of switchable hydrophilicity solvent (SHS)systems (N,N-Dimethylbutylamine (DMBA), water, and carbon dioxide) are investigated at temperatures (283.15, 288.15, 293.15, 298.15, 303.15 and 308.15) K and at atmospheric pressure. VLE of the CO2 loaded DMBA solutions are measured at 298.15 K over the partial pressure range of carbon dioxide from 17.0 to 98.0 kPa. Density data have been used to calculate the apparent molar volumes (Vϕ), limiting apparent molar volumes (Vϕ0) and limiting partial molar expansivity of solute (Eϕ0). The Jones-Dole coefficients B, the Gibbs free energies of activation of viscous flow per mole of solvent (Δμ10≠) and per mole of solute (Δμ20≠), entropies (ΔS20≠) and enthalpies (ΔH20≠) of activation of viscous flow were calculated from experimental viscosity data and discussed in terms of transition state theory. The Walden's product was calculated from the conductance and dynamic viscosity data. The results are valuable sources of information on the design and development of SHSs for novel industrial applications.