Isobaric vapor-liquid equilibrium for chloroform + isopropanol + 1,3-dimethylimidazolium dimethylphosphate at 101.3 kPa

doi:10.1016/j.fluid.2018.03.011

Fluid Phase Equilibria

Volume 466, 25 June 2018, Pages 1-6

https://doi.org/10.1016/j.fluid.2018.03.011 Get rights and content

Abstract

In this study, isobaric vapor-liquid equilibrium (VLE) data for ternary systems of chloroform + isopropanol + 1,3-dimethylimidazolium dimethylphosphate ([MMIM][DMP]) were measured with a modified Othmer still at 101.3 kPa. VLE data were correlated with the non-random two-liquid (NRTL) model and the fitted results showed that [MMIM][DMP] produced a crossover effect between salting-in and salting-out on chloroform, and the minimum [MMim][DMP] concentration needed to break the azeotrope of the chloroform + isopropanol system was 0.045 (mole fraction). In the separation of chloroform and isopropanol by extractive distillation, [MMIM][DMP] was found to be an effective candidate entrainer.

Introduction

Chloroform is one of the most widely used solvents and plays an important role in the pharmaceutical and chemical industry [1]. Chloroform and isopropanol can form an azeotrope. Although extractive distillation is one of the most effective methods in the separation of this azeotropic system, it is difficult to choose an efficient entrainer for breaking the azeotrope [2]. Traditional entrainers, such as solvents and salt, usually have obvious drawbacks [3]. Ionic liquids (ILs) have grown in popularity as promising solvents in different fields of separation technology [4].

ILs are substances formed by relatively large organic cations and inorganic or organic anions [5]. As a new type of green solvent, ILs feature wide temperature ranges, low vapor pressure, good thermal stability, and low viscosity [[6], [7], [8]]. In addition, ILs have characteristic molecular ionization and can play a role similar to inorganic salts in extractive distillation processes [[9], [10], [11], [12]]. Furthermore, ILs have an impact on VLE and relative volatility, which has been verified experimentally in many studies [[13], [14], [15], [16], [17], [18], [19], [20], [21]]. VLE data regarding ILs are essential for studying ILs effects in extractive distillation [22,23] and for understanding the separation rule regarding ILs as well as for developing a thermodynamic model of VLE [24,25].

Although the binary system of chloroform and isopropanol was first studied in the 1960s, few related ternary systems have been studied to date [26]. A search of NIST literature and main journals regarding phase equilibrium has shown that no IL has been selected as an entrainer for breaking this system's azeotrope. [MMim][DMP] might be able to remove the system's azeotropic point, as it is possible to remove the azeotropic point of a similar system involving chloroform + methanol [27]. Consequently, [MMim][DMP] was selected as the candidate entrainer for study here.

In this paper, the VLE data for the binary system chloroform + isopropanol and the ternary system containing [MMIM][DMP] were obtained at 101.3 kPa. In addition, the effects of [MMIM][DMP] on the equilibrium behavior were discussed.

Section snippets

Materials

The chemicals used in this study included chloroform, isopropanol, and [MMIM][DMP] (Table 1). Chloroform and isopropanol (both >99.9%, mass fraction) were obtained from Beijing Chemical Works and purity checked by gas chromatographic (GC) analysis. The IL [MMIM][DMP] (>99%, mass fraction) was supplied by Shanghai Cheng Jie chemical Co. LTD. and also purity checked by GC analysis. The water mass fractions, assessed using the Karl Fischer titration (KF), for chloroform, isopropanol, and

Experimental data

VLE data for the binary system of chloroform (1) + isopropanol (2) were obtained at 101.3 kPa (Table 2), which included measurement of the liquid phase boiling points (T) and chloroform mole fractions in the liquid/vapor phase (x₁/y₁), and the activity coefficient (γ_i) and relative volatility (α₁₂) were calculated. When the vapor phase is considered ideal, the equations of γ_i and α₁₂ are shown as follows: $γ_{i} = \frac{y_{i} P}{x_{i} P_{i}^{S}}$ $α_{12} = \frac{y_{1} / x_{1}}{y_{2} / x_{2}} = \frac{γ_{1} P_{1}^{S}}{γ_{2} P_{2}^{S}}$ where x_i and y_i represents the mole fraction of

Conclusion

VLE data for the binary system chloroform + isopropanol and the ternary system of chloroform + isopropanol + [MMIM][DMP] were measured at 101.3 kPa [MMIM][DMP] addition to the chloroform + isopropanol mixtures presented a crossover effect between the salting-in and salting-out on chloroform, clearly showing that the azeotropic point was removed when the [MMIM][DMP] mole fraction was 0.050.

VLE results were correlated according to the NRTL model and the results found to be in good agreement with

Acknowledgements

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

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Isobaric vapor-liquid equilibrium for chloroform + isopropanol + 1,3-dimethylimidazolium dimethylphosphate at 101.3 kPa

Abstract

Introduction

Section snippets

Materials

Experimental data

Conclusion

Acknowledgements

J. Comput. Chem. Eng.

Fluid Phase Equil.

J. Fluid Phase Equilib.

J. Fluid Phase Equilib.

J. Fluid Phase Equilib.

J. Fluid Phase Equilibria

J. Fluid Phase Equilibria

Ionic liquids for clean technology

J. Chem. Technol. Biotechnol.

Applications of Ionic Liquids in Science and Technology

Ionic liquids: innovative fluids for chemical processing

J. AIChE

Room-temperature ionic liquids and their mixtures: a review

J. Fluid Phase Equilib

Separation of azeotropic mixtures using hyperbranched polymers or ionic liquids

J. AIChE

Influence of ionic liquids on the phase behavior of aqueous azeotropic systems

J. Chem. Eng. Data

Vapor-liquid equilibria of water + alkylimidazolium-based ionic liquids: measurements and perturbedchain statistical associating fluid theory modeling

Ind. Eng. Chem. Res.

Prediction of binary VLE for imidazolium based ionic liquid systems using COSMO-RS

J. Ind. Eng. Chem. Res.

Thermal stability and vapor-liquid equilibrium for imidazolium ionic liquids as alternative reaction media

J. Chem. Eng. Data