Elsevier

Fluid Phase Equilibria

Volume 248, Issue 2, 20 October 2006, Pages 181-190
Fluid Phase Equilibria

Thermodynamics of isomeric hexynes + MTBE binary mixtures

https://doi.org/10.1016/j.fluid.2006.08.007Get rights and content

Abstract

The vapor pressures of liquid hex-1-yne or hex-2-yne + methyl 1,1-dimethylethyl ether (MTBE) binary mixtures and of the three pure components were measured by a static method at several temperatures between 263 and 343 K. These data were correlated with the Antoine equation. Excess molar Gibbs energies GE were calculated for several constant temperatures, taking into account the vapor-phase imperfection in terms of the second molar virial coefficients, and were fitted to the Redlich–Kister equation. Calorimetric excess enthalpy HE measurements, for these binary mixtures, are also reported at 298.15 K. The experimental VLE and HE data were used, examining the binary mixtures hex-1-yne or hex-2-yne + MTBE in the framework of the DISQUAC and modified UNIFAC (Do) models. The DISQUAC calculations, reporting a new set of interaction parameters for the contact carbon–carbon triple bond/oxygen ether, is regarded as a preliminary approach.

Introduction

This paper presents a part of our research work on thermodynamic behaviour of mixtures containing acetylenic hydrocarbons such as hexynes (hex-1-yne, hex-2-yne or hex-3-yne). Previously, we have investigated the binary mixtures of isomeric hexynes with alkanes [1], [2], [3], [4] or alcohols [5], [6]. A survey of the open literature revealed that several thermodynamic studies on the binary mixtures containing acetylenic hydrocarbons have been reported [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33], [34], [35], [36], but it revealed also a scarcity of VLE and HE data on these binary mixtures.

The purpose of the present paper is to extend the existing previous studies on alkyne containing mixtures to systems with tertiary-alkyl ethers. We report new isothermal vapor–liquid equilibria (VLE) data measured at several temperatures from 263 to 343 K and excess molar enthalpies (HE) data measured at 298.15 K, for two binary systems of methyl 1,1-dimethyl ethyl (MTBE) + hex-1-yne or hex-2-yne. These data were analysed in the framework of the DISQUAC [37], [38] and modified UNIFAC (Do) [39], [40], [41] models. The DISQUAC calculations, reporting interaction parameters for the acetylenic carbon–carbon group in the isomeric hexynes and the oxygen group in the ether, are regarded as a preliminary approach.

Section snippets

Materials

Hex-1-yne and methyl 1,1-dimethylethyl ether (Fluka Chem. AG, Buchs, Switzerland) materials of stated purities ≥99.5%, tested by GLC, were used without further purification. Hex-2-yne (Aldrich Chem., Milwaukee, WI, USA) material of stated purity 99%, tested by GLC, was used as received. GLC analysis revealed the presence of traces of impurities in the sample. No further purification was attempted because of the high price of the material. However, all the substances were thoroughly degassed

Results and data reduction

The primary measurements, obtained by the experimental procedure described above, are isoplethal TP data, for the pure components and for the binary mixtures at several constant compositions. These vapor pressure data were correlated with the Antoine equation. Interpolated values at several arbitrarily chosen temperatures, for the pure components and for the binary mixtures at constant compositions, were reported in Table 1, Table 2, respectively.

These interpolated isothermal VLE data were

Modified UNIFAC (Dortmund version)

The modified UNIFAC model developed by Weidlich and Gmehling [39], [40], [41], differs from the original UNIFAC [55] by the combinatorial term and the temperature dependence of the group interaction parameters. The equations used to calculate GE and HE are obtained from the fundamental equation for the activity coefficient γi of component i:lnγi=lnγiCOMB+lnγiRESwhere lnγiCOMB is the combinatorial term and lnγiRES is the residual term.

The combinatorial part was changed in an empirical way

Discussion and conclusion

We examined the influence of the position of the carbon–carbon triple bond, in the hexyne, on thermodynamic properties of the investigated binary mixtures. As expected, we found there is a sizeable difference between the VLE, HE and GE values, for hex-1-yne + MTBE, and those corresponding for hex-2-yne + MTBE. A similar behaviour has been encountered in our previous investigated mixtures of isomeric hexynes with alkanes [1], [2], [3], [4] and with alcohols [5], [6]. The present measurements confirm

References (62)

  • H. Kirss et al.

    Thermochim. Acta

    (1993)
  • T.M. Letcher et al.

    J. Chem. Thermodyn.

    (1987)
  • T.M. Letcher et al.

    Fluid Phase Equilib.

    (1990)
  • T.M. Letcher et al.

    J. Chem. Thermodyn.

    (1988)
  • T.M. Letcher et al.

    Fluid Phase Equilib.

    (1993)
  • T.M. Letcher et al.

    J. Chem. Thermodyn.

    (1999)
  • T.M. Letcher et al.

    J. Chem. Thermodyn.

    (1999)
  • M.K. Kozłowska et al.

    J. Chem. Thermodyn.

    (2004)
  • J.A. Nevines et al.

    J. Chem. Thermodyn.

    (2003)
  • T.M. Letcher et al.

    J. Chem. Thermodyn.

    (2000)
  • T.M. Letcher et al.

    J. Chem. Thermodyn.

    (1999)
  • T.M. Letcher et al.

    J. Chem. Thermodyn.

    (1991)
  • J.A. Gonzalez et al.

    Thermochim. Acta

    (2002)
  • D. Falconieri et al.

    Fluid Phase Equilib.

    (2004)
  • H.V. Kehiaian

    Fluid Phase Equilib.

    (1983)
  • A. Blondel-Telouk et al.

    Fluid Phase Equilib.

    (1995)
  • D. Ambrose et al.

    J. Chem. Thermodyn.

    (1976)
  • J.J. de Llano et al.

    Fluid Phase Equilib.

    (2003)
  • C.R. Chamorro et al.

    Fluid Phase Equilib.

    (2004)
  • M.R. Tiné et al.

    Fluid Phase Equilib.

    (1987)
  • H.V. Kehiaian et al.

    Fluid Phase Equilib.

    (1989)
  • A. Ait-Kaci et al.

    Int. Data Ser., Sel. Data Mixtures, Ser. A

    (1989)
  • B.F. Belaribi et al.

    Int. Data Ser., Sel. Data Mixtures, Ser. A

    (1991)
  • A. Ait-Kaci et al.

    Int. Data Ser., Sel. Data Mixtures, Ser. A

    (1992)
  • G. Belaribi-Boukais et al.

    Fluid Phase Equilib.

    (2000)
  • G. Belaribi-Boukais et al.

    Int. Electron. J. Phys. Chem. Data

    (1997)
  • G. Belaribi-Boukais et al.

    Int. Electron. J. Phys. Chem. Data

    (1997)
  • E. Wilhelm et al.

    Monatsch. Chem.

    (1978)
  • E. Wilhelm et al.

    Monatsch. Chem.

    (1978)
  • E.K. Otsa et al.

    Monatsh. Chem.

    (1980)
  • L.S. Kudryavtseva et al.

    Eesti Nsv Tead Akad. Toim. Keem. Geol.

    (1968)
  • Cited by (12)

    • Excess molar enthalpies of binary mixtures of n-octane, isooctane and cyclooctane with morpholine, 1,4-dioxane, piperidine, oxane, N-methyl piperidine and cyclohexane. Experimental results and DISQUAC modelling

      2015, Journal of Molecular Liquids
      Citation Excerpt :

      Excess molar enthalpies, HE, for the investigated mixtures, were calculated using DISQUAC [7,8], a purely physical model based on the rigid lattice theory developed by Guggenheim [9]. The DISQUAC model equations are the same as in other applications [42,44–46]. The parameters, for theoretical calculations, are all available in the literature [39].

    View all citing articles on Scopus
    View full text