Influence of Temperature on the Liquid–Liquid Phase Equilibria of Ternary (Water + Alcohol + Entrainer) Systems

Abstract

The effect of temperature on the liquid–liquid equilibrium (LLE) phase behavior of ternary (water + alcohol + entrainer) systems comprised of the alcohols ethanol, isopropanol, and n-propanol and the entrainers diisopropyl ether (DIPE), cyclohexane, and isooctane (excluding (water + n-propanol + DIPE)) was investigated for application to the decanter in heterogeneous azeotropic distillation. LLE data were measured at ambient pressure for the (water + isopropanol + cyclohexane), (water + isopropanol + isooctane), and (water + n-propanol + isooctane) systems at 308.2 and 318.2 K and for the (water + n-propanol + cyclohexane) and (water + ethanol + isooctane) systems at 318.2 K. These data, in conjunction with literature LLE data, show that temperature has an effect on all systems investigated. As temperature increases, the aqueous phase becomes depleted of and the organic phase becomes enriched in alcohol. It appears that component polarities play an important role in explaining the phase behavior. The systems were correlated with the NRTL and UNIQUAC ACMs in Aspen Plus V8.2, but reliable correlations were only obtained for the (water + ethanol + DIPE/cyclohexane/isooctane) and (water + ethanol/isopropanol/n-propanol + cyclohexane) systems. These correlations were used to simulate the decanter water recoveries over a range of temperatures.

Generic Nature of Interfacial Phenomena in Solutions of Nonionic Hydrotropes

“…With temperature rise, the critical point gradually shifts toward the water vertex, forming the critical line at the separation surface (shown as a black solid line in Figure a). Such a change in the position of the critical point in the ternary system with increasing temperature is associated with a depletion of the water phase with TBA and CHX and was previously observed for other combinations of hydrotropes and hydrocarbons. − …”

Experiment and Correlation of Liquid–Liquid Equilibrium Data for Water + 2-Propanol + 1-Octanol or n-Propyl Acetate at 298.2, 308.2, and 318.2 K under 101.3 kPa

“…There are few studies on alcohols as extractants, and this work also studies the liquid–liquid behavior of water + IPA + 1-octanol. However, the current research − on the LLE data of IPA and water systems at different temperatures is still insufficient. Therefore, it is urgent to obtain more reliable LLE data to realize industrial extraction and separation of IPA and water.…”

Separation of isopropanol from its aqueous solution with deep eutectic solvents: liquid–liquid equilibrium measurement and thermodynamic modeling

“…For liquid-liquid extraction, the selection of extractant is of importance, which can significantly affect extraction performance. Usually, organic solvents are considered as extractants in the extraction process, such as esters (Abu Al-Rub and Datta 1999;Zheng et al 2016;Wu et al 2008;Sun et al 2017;Liu et al 2018b), ethers (Swanepoel and Schwarz 2017;Letcher et al 1992), heavy alcohols (Wang and Liu 2012;Xu et al 2016;Gilani et al 2012a, b;Yang et al 2013) and ketones (Cháfer et al 2012(Cháfer et al , 2014. However, the organic solvents have limitations in chemical separation applications due to their volatility, toxicity and flammability, and the organic solvents should be recovered by distillation with more energy consumption.…”