Elsevier

Fluid Phase Equilibria

Volume 399, 15 August 2015, Pages 16-21
Fluid Phase Equilibria

Liquid–liquid equilibria for the ternary system water + octane + 2-butyloxy-ethanol

https://doi.org/10.1016/j.fluid.2015.04.019Get rights and content

Highlights

  • A ternary system water + octane + 2-butyloxyethanol was chosen.

  • The fish-shaped phase diagram of the ternary system was reported.

  • The upper and lower critical solution temperatures of the system were, respectively, 296.90 and 286.10 K.

  • LLE data for this ternary system were determined at T = 283.15, 293.15 and 303.15 K under atmospheric pressure.

  • The NRTL model was applied to correlate the experimental data.

Abstract

Experiment of the fish-shaped phase diagram of the ternary water + octane + 2-butyloxy-ethanol system under atmospheric pressure was performed at constant water/octane mass ratio (1/1) to determine the upper critical solution temperature (UCST = 296.90 ± 0.05 K) and the lower critical solution temperature (LCST = 286.10 ± 0.05 K). The liquid–liquid equilibria of the water + octane + 2-butyloxy-ethanol system at 283.15, 293.15 and 303.15 K were measured under atmospheric pressure. At 283.15 and 303.15 K, there is only one two-liquid-phase-coexisting envelop in the triangle phase diagram. At 293.15 K, in-between the UCST and LCST, the system exhibits three two-liquid-phase-coexisting envelops and one three-liquid-phase-coexisting tie triangle in the triangle phase diagram. The experimental results of liquid–liquid equilibria were further correlated with the nonrandom two-liquid (NRTL) model.

Introduction

Mixtures of the type water + oil + surfactant are widely applied in many industrial processes and applications, e.g., pharmaceuticals, liquid–liquid extraction, herbicides, tertiary oil recovery and in the fundamental research of wetting transitions and critical phenomena [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11]. The homologous series of nonionic surfactant polyoxyethylene alcohol CH3(CH2)i−1(OCH2CH2)jOH, abbreviated by CiEj hereafter, are extensively used as detergents and emulsifying agents and also applied both in industrial and in fundamental research [7], [8], [9], [10], [11], [12], [13].

Kilpatrick et al. [14] have studied the phase behavior of water + CnH2n+2 (n = 6, 8, 10, 12, 14) + C4E1 at 298.15 and 303.15 K. Precise liquid–liquid equilibrium measurement data of water + decane + C4E1 mixture has been investigated by Brandani et al. [15] On the other hand, Lin and Chen [16], [17] have reported the phase diagrams of water + dodecane + C4E1 and of water + tetradecane + C4E1 system at temperatures ranging from 298.15 to 338.15 K. Su et al. [18], [19], [20], [21], [22], [23] replaced the ethylene glycol ethers with propylene glycol ethers (CH3(CH2)i−1(OCH2CHCH3)jOH, abbreviated by CiPj), and performed a series of liquid–liquid equilibrium measurements for the water + CnH2n+2 (n = 12, 14, 16) + C3Pj (j = 1, 2) system at three different temperatures.

In this study, liquid–liquid equilibrium data were measured for the ternary system water + octane + 2-butyloxy-ethanol (C4E1) in the temperature range from 283.15 to 303.15 K under atmospheric pressure by gas chromatography. The fish-shaped phase diagram of the system was also performed to search for the lower/upper critical solution temperatures. These experimental liquid–liquid equilibrium data were further correlated with the NRTL model successfully.

Section snippets

Experimental

The nonionic surfactant 2-butyloxy-ethanol (C4E1) was an Aldrich Chemical product with a purity of >0.990 and was fractionally distilled under reduced pressure. The purity of the distilled C4E1 was better than mass fraction 0.995 determined by gas chromatography. Octane (C8H18) with a purity of 0.990 was purchased from Alfa Aesar Co. and was used as received. Water was purified by double distillation and then followed by a PURELAB Maxima Series (ELGA Labwater) purification system with the

Results and discussion

Fig. 1 shows the fish-shaped phase diagram of the ternary water + octane + C4E1 system. According to Winsor’s classification [32], phase equilibria of the water + oil + surfactant system can be classified into four types and all these four types of phase equilibria can be found in the fish-shaped phase diagram of the ternary water + octane + C4E1 system, Fig. 1. Inside the fish body, the system exhibits three-liquid-phase-coexisting, identified by 3φ in Fig. 1, that is, the Winsor’s type III phase

Conclusion

The fish-shaped phase diagram and the triangle phase diagram plotted according to liquid–liquid equilibrium data of the water + octane + C4E1 system were performed under atmosphere pressure. The UCST and LCST of the system are 296.90 ± 0.05 K and 286.10 ± 0.05 K, respectively. There is one two- to three- and one three- to two-liquid-phase-coexisting transition when the temperature increases from 283.15 K and 303.15K. The NRTL model can well describe the phase behavior of the water + octane + C4E1 system.

Acknowledgement

This work was supported by the Ministry of Science and Technology of Taiwan.

References (34)

  • P.A. Ash et al.

    Curr. Opin. Colloid Interface Sci.

    (2012)
  • S. Brandani et al.

    Fluid Phase Equilib.

    (1994)
  • B.J. Lin et al.

    Fluid Phase Equilib.

    (2004)
  • C.H. Su et al.

    J. Chem. Thermodyn.

    (2012)
  • C.H. Su et al.

    Fluid Phase Equilib.

    (2013)
  • C.H. Su et al.

    Fluid Phase Equilib.

    (2013)
  • A. Rodrı́guez et al.

    J. Chem. Thermodyn.

    (2003)
  • J.S. Matos et al.

    Fluid Phase Equilib.

    (2001)
  • Y.H. Pai et al.

    Fluid Phase Equilib.

    (1999)
  • A. Ćwiklińska et al.

    J. Chem. Thermodyn.

    (2011)
  • J. Eastoe

    Colloid Science: Principles, Methods and Applications

  • T. Sottmann et al.

    Microemulsions: Background, New Concepts, Applications, Perspectives

  • R.F. Tabor et al.

    Langmuir

    (2013)
  • C.K. Wu et al.

    J. Phys. Chem. B

    (2006)
  • N.D. Gullickson et al.
  • R.B. Mistry et al.

    Int. J. Pharm. Sci.

    (2011)
  • C.K. Wu et al.

    Langmuir

    (2005)
  • Cited by (6)

    • Diesel removal and recovery from heavily diesel-contaminated soil based on three-liquid-phase equilibria of diesel + 2-butyloxyethanol + water

      2023, Journal of Hazardous Materials
      Citation Excerpt :

      All of the above characteristics, including the phase equilibrium region distribution and variation tendency, were similar to the literature conclusions regarding the phase behavior of water + surfactant + alkane. The determination of the ternary Gibbs phase diagram could provide guidance for the TPS formulation and control the solution composition within the tie-triangle region to ensure a constant three-liquid phase equilibrium state (Alonso et al., 2020; Chen and Chen, 2015; Pal et al., 2019). In general, fish-shaped phase diagrams are used to describe the phase behavior of microemulsions.

    • Fish-shaped diagram of liquid–liquid equilibria for the mixtures water + n-alkane + n-alkyl polyglycol ether

      2022, Fluid Phase Equilibria
      Citation Excerpt :

      In these measurements, the C4E1 or C6E2 free basis mass fraction of n-octane or n-dodecane, “α”, was changed from 0.1 to 0.9 in order to investigate the change in the behavior of fish-shaped diagrams with the change in α. For the mixtures of water + n-octane + C4E1 and water + n-dodecane + C6E2, the phase diagrams at α = 0.5 have been reported by Andersen et al. [4], Chen and Chen [38], and Hu et al. [32]. Thus, initially, the experimental apparatus and procedures of the fish-shaped diagrams were verified by comparing our experimental data with these literature values.

    • Liquid-liquid equilibrium for the ternary system of isopropyl acetate + 2-propanol + glycerol at different temperatures under atmospheric pressure

      2016, Fluid Phase Equilibria
      Citation Excerpt :

      The LLE experiment was carried out in a 30 mL glass cell with a magnetic stirrer in it. The experimental method was described in literature [13–15]. In this study it was specified as follows: The temperature of the system was controlled by a refrigerated heating circulator (Julabo FP45-HF, German, temperature stability ±0.01 K) and measured by a platinum resistance thermometer Pt-100 (calibrated with an accuracy of 0.01 K).

    View full text