Liquid-liquid equilibrium data for ternary mixtures (water plus isopropanol+1-pentanol/1-hexanol/1-heptanol) at 298.15 K: Measurement, correlation and prediction

To recover isopropanol from its aqueous solution, alkanols (1-pentanol, 1-hexanol and 1-heptanol) were selected as the solvents to separate water and isopropanol. Liquid-liquid equilibrium data for water + isopropanol + 1-pentanol/1-hexanol/1-heptanol ternary systems were measured at 298.15 K under 101.3 kPa. The mass conservation of the experimental data was checked, and the reliability of the tie-lie data were evaluated by the Bachman, Hand and Othmer-Tobias equations. The extraction performance of the three solvents was assessed through the separation factor and partition coefficient, and compared with those for other reported solvents {esters, ketones, ethers, alkanes (or alkenes), ionic liquids and deep eutectic solvents}, indicating that 1-heptanol has better extraction performance for isopropanol compared with other two solvents. The NRTL and UNIQUAC models were used to correlate the data to obtain regression parameters. The mixed surface analysis based on Gibbs energy topology verified that the binary interaction parameters are consistent with the measured data. Furthermore, the LLE binodal curve for the researched ternary systems were predicted through the UNIFAC and COSMO-UNIFAC models.

Automated summary

In this study, alkanols were used as solvents to recover isopropanol from its aqueous solution. The extraction performance of three solvents were evaluated and compared, and 1-heptanol was found to have better performance. Regression parameters were obtained using NRTL and UNIQUAC models, and the LLE binodal curve for the ternary systems were predicted using UNIFAC and COSMO-UNIFAC models.