Study Of Liquid-liquid Phase Equilibrium Of Isopropanol From Its Aqueous Solution

Isopropanol(IPA)is an excellent chemical raw material and organic solvent,which has a wide range of applications in chemical industry.Usually,it can be produced by industrial process where the mixture of isopropanol and water are always generated together.However,the mixture of isopropanol and water forms a minimum boiling azeotrope at Taze=80.3?,the azeotropic and decompressing distillation are adopted to separate isopropanol and water,but it's too expensive to spend on energy consumption and equipment.Among the different available separating technologies,liquid-liquid extraction is a promising method to separate isopropanol from its aqueous solution,and the study of the system separated by liquid-liquid extraction process has a strong association with the measurement of the liquid-liquid equilibrium data of isopropanol from its aqueous solution.But the research of liquid-liquid equilibrium data of isopropanol from its aqueous solution is insufficient.In order to provide basic data for the simulation and design of liquid-liquid extraction process about isopropanol,the liquid-liquid equilibrium data for the ternary systems isopropanol+water+extractant were measured.the main contents are as follows:First,the liquid-liquid equilibrium(LLE)data for the ternary systems(isobutyl acetate/butyl acetate/butyl propionate)+isopropanol+ water were measured at T=298.15 K and T=318.15 K under 101.3 kPa.Othmer-Tobias and Bachman equations were selected to check and confirm the reliability of the measured tie-line data,and the correlation coefficient(R2)were all close to 1.In addition,the nonrandom two-liquid(NRTL)and universal quasi-chemical(UNIQUAC)activity coefficient models were applied to correlate the experimental data,and the values of the root mean square deviations(RMSD)were less than 1%.which indicate that the experimental LLE data can be successfully correlated by both the NRTL and the UNIQUAC models.Compared with the distribution coefficient and separation factor of different systems,it can be concluded that the extraction capacity of butyl propionate is the best.Secondly,liquid-liquid extraction using hydrophobic deep eutectic solvents(HDESs)is explored to separate binary azeotropic mixtures of isopropanol and water.NMR spectrometer was used to characterize the HDES before and after use to ensure the consistency of its structure.Three HDESs were selected for experimental validation where methyl trioctyl ammonium chloride as hydrogen bond acceptor(HBA)and butanol,hexanol and decanol as hydrogen bond donors(HBDs).The hydrogen spectrum is used to characterize the HDES to ensuring the consistency of its structure.Ternary liquid-liquid extraction experimental were conducted at 298.15 K and 308.15 K under 101.3 KPa with the HDES.Othmer-Tobias and Hand equations were selected to check and confirm the reliability of the measured tie-line data,and the correlation coefficient(R2)were all close to 1.In addition,the nonrandom two-liquid(NRTL)activity coefficient model was applied to correlate the experimental data,and the values of the root mean square deviations(RMSD)were less than 1%.which indicate that the experimental LLE data can be successfully correlated by both the NRTL model.Compared with the distribution coefficient and separation factor of three HDESs,HDES3 is a desirable extractant.