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This paper investigates the feasibility of using diethyl adipate (DEA), a green organic solvent, as a separation agent for extracting various alcohols from aqueous solutions. In order to achieve this, liquid-liquid equilibria (LLE) experiments were carried out for four ternary systems: {water + methanol + DEA}, {water + ethanol + DEA}, {water + 1-propanol + DEA}, and {water + 2-propanol + DEA} at 298.15 K and atmospheric pressure. LLE experiments involve determination of certain thermodynamic data such as binodal curves and cloud-point data. Binodal curve data were determined by the cloud-point method using the titration technique, while the tie-line data were determined by optimizing the parameters based on the experimental measurements of the refractive index. Additionally, the distribution coefficients and the separation factors were calculated within the immiscibility region. Hand and Othmer-Tobias correlations were used to examine the reliability of the tie-line data. Also, the experimental ternary LLE data were correlated using the UNIversal QUAsiChemical (UNIQUAC) activity coefficient models. The results confirm that that DEA is a suitable choice for extracting methanol, ethanol, 1-propanol, and 2-propanol from water. The potential of DEA as a separation agent followed the sequence methanol < ethanol < 2-propanol < 1-propanol. UNIQUAC model proved to be effective in correlating the LLE data.

This paper investigates the feasibility of using diethyl adipate (DEA), a green organic solvent, as a separation agent for extracting various alcohols from aqueous solutions. In order to achieve this, liquid-liquid equilibria (LLE) experiments were carried out for four ternary systems: {water + methanol + DEA}, {water + ethanol + DEA}, {water + 1-propanol + DEA}, and {water + 2-propanol + DEA} at 298.15 K and atmospheric pressure. LLE experiments involve determination of certain thermodynamic data such as binodal curves and cloud-point data. Binodal curve data were determined by the cloud-point method using the titration technique, while the tie-line data were determined by optimizing the parameters based on the experimental measurements of the refractive index. Additionally, the distribution coefficients and the separation factors were calculated within the immiscibility region. Hand and Othmer-Tobias correlations were used to examine the reliability of the tie-line data. Also, the experimental ternary LLE data were correlated using the UNIversal QUAsiChemical (UNIQUAC) activity coefficient models. The results confirm that that DEA is a suitable choice for extracting methanol, ethanol, 1-propanol, and 2-propanol from water. The potential of DEA as a separation agent followed the sequence methanol < ethanol < 2-propanol < 1-propanol. UNIQUAC model proved to be effective in correlating the LLE data.

Ethylene glycol is recognized as a heat transfer fluid. To improve its performance, caffeine is added to pure ethylene glycol. The experimental measurements of densities at pressures of up to 60 MPa and in the range of temperatures 293.15-413.15 K were performed. Obtained experimental results were fitted by the modified Tammann-Tait equation, and parameters were used to determine some valuable thermodynamic and mechanical properties, the isothermal compressibility, the isobaric thermal expansibility, the internal pressure, and the difference of specific heat capacity at constant pressure and constant volume. The same approach was applied to the equimolar mixture of ethylene glycol and water. The results confirm negligible changes in the investigated thermodynamic properties with the addition of caffeine into pure ethylene glycol and significantly smaller dependence on temperature compared to the mixture of ethylene glycol and water.

Densities, refractive indices, and viscosities of 1-amino-2-propanol (monoisopropanolamine (MIPA)) + 1-butanol and 1-amino-2-propanol + 2-butanol solutions are reported over the entire range of mole fractions and the temperature range from (288.15 to 333.15) K. The Redlich-Kister relation was used for correlation of measured results of excess molar volumes, viscosities, and refractive indices as a function of temperature and composition. Partial molar volumes at infinite dilution were determined from apparent molar volumes. Negative values for excess molar volumes, refractive indices, and viscosity deviations are observed over the entire composition range. The viscosities of 1-amino-2-propanol with 1-butanol and 1-amino-2-propanol with 2-butanol are well represented by an Arrhenius equation. Activation energies for viscous flows are determined by linearization of the Arrhenius equation, providing a clear explanation of the influence on hydrogen bonding. In order to confirm molecular interactions between compounds obtained by analysis of infinite dilution of solute, a FT-IR spectroscopy study was performed at T = 298.15 K. Interactional and structural effects were investigated through calculations of excess Gibbs free energy of activation of viscous flow.