Elsevier

Fluid Phase Equilibria

Volume 361, 15 January 2014, Pages 116-129
Fluid Phase Equilibria

Phase equilibria and excess molar enthalpies study of the binary systems (pyrrole + hydrocarbon, or an alcohol) and modeling

https://doi.org/10.1016/j.fluid.2013.10.029Get rights and content

Highlights

  • Measurements of phase diagrams of pyrrole with hydrocarbons and alcohols.

  • Density measurements and VmE of pyrrole with pyridine.

  • Measurements of HmE of pyrrole with hydrocarbons and alcohols.

  • The Mod. UNIFAC (Do) and DISQUAC group contribution models.

  • The new interaction parameters.

Abstract

Isothermal vapour–liquid equilibrium data (VLE) have been measured by an ebulliometric method for the binary mixtures of {pyrrole (1) + benzene, or pyridine, or cyclohexane (2)} at three temperatures (338.15, 348.15 and 358.15 K). Binary systems with pyridine were measured at higher temperatures (353.15, 363.15 and 373.15 K). The densities and excess molar volumes (VmE) of {pyrrole (1) + pyridine (2)} over temperature range (298.15–338.15 K) were developed. The excess molar enthalpies (HmE) of binary systems of {pyrrole (1) + benzene, or pyridine, or cyclohexane, or 1-propanol, or 1-butanol, or 1-pentanol (2)} at temperature T = 298.15 K have been measured. Well-known non-random two liquids (NRTL) equation and the Redlich–Kister equation has been used to correlate the experimental VLE data sets and HmE, respectively. Using the data presented in this work and published by us earlier, the interaction parameters have been determined for Mod. UNIFAC (Do) and DISQUAC models for the systems {pyrrole (1) + benzene, or pyridine, or cyclohexane (2)}. Both models described experimental data with similar accuracy. The DISQUAC model predicts liquid–liquid equilibrium (LLE) in system (pyrrole + cyclohexane) which is in agreement with the experiment, whereas Mod. UNIFAC (Do) predicts simple eutectic system. In case of binary systems with alcohols, the interaction parameters could not accurately describe the experimental data.

Introduction

New data of phase equilibria and excess molar enthalpies are useful tools for determining parameters for group contribution models. Pyrrole may be used for the determining the parameters of the NH(arom) group existing in pyrrole and in the imidazoles (see Fig. 1).

The most popular imidazolium ionic liquids with different substituents may be better described by the group contribution methods with using good interaction parameters for pure imidazoles. The first modeling connected with the imidazoles was already made by us with the group contribution method DISQUAC [1], [2]. The DISQUAC interaction parameters have been determined from solid/liquid–liquid phase equilibria for {1H-imidazole + 1-alkanol, or hydrocarbons} mixtures [3]. Parameters were characterized for the contacts present in the solution with aliphatic hydrocarbons, aromatic hydrocarbons and for the amine/hydroxyl contacts from the solutions with hydrocarbons and alcohols [3]. The quasichemical interaction parameters were the same for mixtures containing 1H-imidazole, 1-methylimidazole and 2-methyl-1H-imidazole. Unfortunately, it was impossible to describe the LLE in many of binary systems measured by us earlier. The new idea was to measure new data for pyrrole and to use new NH(arom) group coming from pyrrole to make the description, not only of pyrrole, but also improve the prediction of phase equilibria of imidazoles and in the future the imidazolium-based ionic liquids.

In this point it is necessary to mentioned that the Mod. UNIFAC (Do) group interaction parameters [4], [5], [6] were already determined for the imidazolium bis{(trfluoromethyl)sulfonyl}imides with alkanes, alkenes, cyclic hydrocarbons and alcohols giving good results in the prediction of vapour–liquid equilibria (VLE), activity coefficients at infinite dilution and excess molar enthalpies (HmE) [7], [8], [9]. The parameters were developed for imidazolium ring and for anion as separate groups.

This work is a continuation of the phase equilibria measurements of pyrrole with hydrocarbons and alcohols. The experimental solid–liquid phase equilibria (SLE) and liquid–liquid phase equilibria (LLE) measurements of pyrrole with benzene, cyclohexane and hexane [10] and the isobaric and isothermal vapour–liquid equilibria of pyrrole and short chain alcohols were presented in our earlier work [11].

Pyrrole and its derivatives have unique physical and chemical properties and are used in many different fields of technology: in electrochemistry, as an entrainers, in photochemistry and many others processes [12], [13]. However, the physico-chemical properties and phase equilibria were measured only for few binary mixtures [14], [15], [16], [17], [18], [19], [20]. The viscosities of pyrrole in binary mixtures with many other organic compounds were measured very early [14]. Vapor–liquid equilibrium measurements of pyrrole with water made this compound suggested to use it as entrainer in extraction processes from water [15]. Monte Carlo simulation was carried out to compute the vapour–liquid equilibria of pyrrole with other aromatic compounds [16]. High pressure phase equilibria of pyrrole with carbon dioxide was measured as an important compound in the enzymatic reactions [17], [18]. Ternary LLE was measured for (pyrrole + hexadecane + nitrogen compound) as an information in the possible extraction of sulfur compounds from vehicle diesel [19], [20]. It was proved by the measurements of the isothermal VLE data for (pyrrole + pyridine) binary system at temperatures T = 353.20 K and T = 383.20 K that the negative deviations from ideal behavior exists in this mixture [21].

These are not sufficient results for an industrial use and possibility for prediction of phase equilibria of different mixtures. Thus, the interaction parameters for the group contribution methods for similar compounds are of industrial importance.

Here, we continue our experimental work extending the available database on systems with pyrrole. The present study is the forth of the series of characterization of the (pyrrole + organic solvent) binary mixtures. This work is concerned with the investigation of isothermal vapour–liquid equilibrium data for the binary mixtures of {pyrrole + benzene, or pyridine, or cyclohexane} at three temperatures (338.15, 348.15 and 358.15 K). Binary systems with pyridine were measured at higher temperatures (353.15, 363.15 and 373.15 K). The densities and excess molar volumes (VmE) of {pyrrole (1) + pyridine (2)} over temperature range (298.15–338.15 K. The excess molar enthalpies (HmE) of binary systems were measured of {pyrrole + benzene, or pyridine, or cyclohexane, or 1-propanol, or 1-butanol, or 1-pentanol} at temperature T = 298.15 K.

Knowledge of the phase equilibria VLE, or LLE and SLE are fundamental to give the first information for the predictive methods as Mod. UNIFAC (Do), or DISQUAC. Our new experimental data and literature data were used to optimize the new pair of group interaction parameters for contacts between pyrrole-groups and benzene, or pyridine, or cyclohexane, or alcohols. The Mod. UNIFAC (Do) and DISQUAC group contribution methods, using available data for various systems of pyrrole with alkanes, cyclohexane, aromatic hydrocarbons and alcohols were discussed.

Section snippets

Materials

The purity in mass fraction and supplier of each of the compounds were as follow: pyrrole (Across Organic, 0.99), benzene (POCH, 0.997), pyridine (Across Organic, 0.999), cyclohexane (Sigma–Aldrich Chemie GmbH, Steinheim, Germany, 0.995), 1-propanol (Sigma–Aldrich Chemie GmbH, Steinheim, Germany, 0.999), 1-butanol (Sigma–Aldrich Chemie GmbH, Steinheim, Germany, 0.998, 1-pentanol, (Sigma–Aldrich Chemie GmbH, Steinheim, Germany, 0.995). Before use, they were fractionally distilled over different

Density data discussion

The experimental density of two systems {pyrrole (1) + benzene, or cyclohexane (2)} at different temperatures was presented in our previous work [10]. The negative excess molar volumes were observed for these two mixtures. The densities for the system {pyrrole (1) + pyridine (2)} were measured at temperature range 298.15–338.15 K. As always, densities decreases with an increasing temperature for pure substances and for mixtures. Eq. (1) was found to satisfactory correlate the changes of density with

Modeling

The Mod. UNIFAC (Do) group contribution model [4] based on the local composition concept with temperature-dependent parameters needs four parameters per contact (two for excess free molar energy and two for excess molar enthalpy) to reproduce GE and HmE as well as two heat capacity parameters, if available. However, the Mod. UNIFAC (Do) is used to described thousands of systems with its parameter matrix [5], [6], the possibility of new parameters for (pyrrole + benzene, or pyridine, or

Conclusion

In summary, the experimental and theoretical study of some binary systems involving pyrrole and molecular solvents was presented. Typical results of VLE, observed for system with the small and strong interactions between dissimilar molecules were obtained including: (1) S-shaped VmE data for the mixture (pyrrole + pyridine); (2) positive deviations from Raoult's law phase equilibria studied and positive (endothermic) HmE values for (pyrrole + benzene, or cyclohexane); (3) negative deviations from

Acknowledgements

Funding for this research was provided by the Warsaw University of Technology. Authors wish to thank Prof. J. Gmehling and Dortmund Data Bank for the VLE experimental data for (pyrrole + pyridine) used for comparison with our data.

References (31)

  • H.V. Kehiaian

    Fluid Phase Equilib.

    (1983)
  • U. Domańska et al.

    J. Chem. Thermodyn.

    (2010)
  • R. Kato et al.

    J. Fluid Phase Equilib.

    (2004)
  • R. Kato et al.

    J. Chem. Thermodyn.

    (2005)
  • B. Mokhtarani et al.

    J. Chem. Thermodyn.

    (2010)
  • A.F.L.O.M. Santos et al.

    J. Chem. Thermodyn.

    (2010)
  • B. Kulik et al.

    J. Supercrit. Fluids

    (2008)
  • K. Thamanavat et al.

    Fluid Phase Equilib.

    (2009)
  • U. Domańska et al.

    J. Chem. Thermodyn.

    (2005)
  • T. Sancho et al.

    J. Chem. Thermodyn.

    (1990)
  • H.V. Kehiaian

    Pure Appl. Chem.

    (1985)
  • U. Weidlich et al.

    Ind. Eng. Chem. Res.

    (1987)
  • J. Gmehling et al.

    Ind. Eng. Chem. Res.

    (1993)
  • J. Gmehling et al.

    Ind. Eng. Chem. Res.

    (1998)
  • U. Domańska et al.

    J. Chem. Eng. Data

    (2010)
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