Isothermal vapor–liquid equilibria and excess molar volumes for the ternary mixtures containing 2-methyl pyrazine

doi:10.1016/S0378-3812(01)00639-2

Fluid Phase Equilibria

Volume 193, Issues 1–2, 30 January 2002, Pages 109-121

https://doi.org/10.1016/S0378-3812(01)00639-2 Get rights and content

Abstract

Isothermal vapor–liquid equilibrium (VLE) data at 353.15 K and excess molar volumes (V^E) at 298.15 K are reported for the binary systems of ethyl acetate (EA)+cyclohexane and EA+n-hexane and also for the ternary systems of EA+cyclohexane+2-methyl pyrazine (2MP) and EA+n-hexane+2MP. The experimental binary VLE data were correlated with common g^E model equations. The correlated Wilson parameters of the constituent binary systems were used to calculate the phase behavior of the ternary mixtures. The calculated ternary VLE data using Wilson parameters were compared with experimental ternary data. The experimental excess molar volumes were correlated with the Redlich–Kister equation for the binary mixtures, and Cibulka’s equation for the ternary mixtures.

Introduction

Studies on phase equilibria and excess molar properties (V^E, H^E, η^E, …) of liquid mixtures are of considerable importance for the design of separation processes and theoretical understanding the nature of molecular behavior [1]. Many investigations of vapor–liquid equilibrium (VLE) and excess properties have already been carried out for binary mixtures, while that of ternary mixtures are rare in the literature. Especially, the excess properties for ternary mixtures, required to get insight into the nature and degree of interactions, are quite rare. It is therefore interesting to estimate excess functions of ternary mixtures from binary data [2], [3].

2-Methyl pyrazine (2MP) has several commercial applications, especially as a pharmaceutical intermediate compound for anti tuberculosis. However, during the synthesis of 2MP, a separation problem has to be solved, since the nitric compound (2MP) and water show azeotropic behavior. Usually, 2MP has been purified from aqueous product by distillation with NaOH as entrainer, however, this process has some environmental and corrosion problems. If suitable solvents can be found, it can probably be more economically and environmental friendly separated by azeotropic or extractive distillation from the aqueous solution. For the selection of appropriate entrainers and for designing these separation processes properly, the phase behavior and thermodynamic properties of mixtures containing 2MP have to be known. A quick literature survey does not reveal any experimental and estimated data on the phase equilibria and mixture properties for the mixtures containing 2MP. In previous works [4], [5], we have therefore reported isothermal VLE and LLE data and excess molar volumes for some binary mixtures of 2MP with water and solvents; n-hexane, cyclohexane, n-heptane, methylcyclopentane (MCP), methylcyclohexane (MCH) and ethyl acetate (EA).

The present work on the isothermal VLE data at 353.15 K and the excess molar volumes at 298.15 K for the binary systems of EA(1)+cyclohexane(2) and EA(1)+n-hexane(2) or for the ternary systems of EA(1)+cyclohexane(2)+2MP(3) and EA(1)+n-hexane(2)+2MP(3) at the same conditions are in a systematic study on thermophysical data of the 2MP mixtures. The other necessary corresponding binary data for the calculation of ternary systems were taken from our previous work [4]. The experimental binary VLE data were correlated using common g^E model equations; Margules, van Laar, Wilson, NRTL. While the ternary VLE data were compared with calculated data using binary Wilson parameters. The experimental excess molar volumes were correlated using Redlich–Kister polynomial [6] and Cibulka’s equation [7] for the binary and ternary systems, respectively.

Section snippets

Materials

All the chemicals used in this investigation were of analytical commercial grade of purity and doubly distilled water. 2MP was from Aldrich Chemical Co., and other chemicals were supplied from Junsei Chemical Co. They were used after water has been removed using molecular sieves with a pore diameter of 0.4 nm. The purity of chemicals was checked by gas chromatography and by measuring densities and comparing with values reported in the literature. The water content of chemicals by Karl–Fisher

Isothermal VLE

To calculate the true liquid mole compositions, the thermophysical data for SRK equation were adopted from pure component properties stored in the DDB [11] and Reid et al. [12]. Vapor pressures of the pure component at 353.15 K were calculated using the Antoine equation. The used Antoine constants are listed in Table 1. In the HSGC method, the equilibrium pressure can not be measured but calculated from experimental vapor-phase mole compositions and thermodynamic equations [4], [8], [9], [10].

Conclusion

New isothermal VLE data at 353.15 K and excess molar volumes (V^E) at 298.15 K were experimentally determined for the binary systems of EA(1)+cyclohexane(2) and EA(1)+n-hexane(2) and also for the ternary systems of EA(1)+cyclohexane(2)+2MP(3) and EA(1)+n-hexane(2)+2MP(3) using the HSGC method. The binary VLE data show minimum boiling azeotropes and they can be correlated reliably with common g^E model equations. Using the binary Wilson parameters, a satisfactory prediction of the ternary VLE data

Acknowledgements

This work was supported by Grant No. 2000-1-30700-011-2 from the Basic Research Program of the Korea Science and Engineering Foundation.

References (13)

G.C Pedrosa et al.
Thermochim. Acta
(1990)
S Martinez et al.
Fluid Phase Equilib.
(2000)
S.J Park et al.
Fluid Phase Equilib.
(2001)
N Radojkovic et al.
J. Chem. Thermodyn.
(1977)
M Dominguez et al.
Can. J. Chem.
(1995)
S.J. Park, D.B. Won, H.H. Kim, B.H. Kim, S.B. Lee, M.J. Choi, Hwahak Konghak, 39...

There are more references available in the full text version of this article.

Cited by (8)

Jacobson's intermolecular free lengths in liquid mixtures – A thermodynamic approach
2023, Journal of Chemical Thermodynamics
Jacobson’s intermolecular free length is a quantity related to molar volume and the internal surface of a liquid. A difference between intermolecular free length in a mixture and that calculated from the free lengths in its pure components results from molecular interactions. Commonly, the mole-fraction-weighted average of the intermolecular free lengths is a reference function in such calculations. The reference state lacking physical meaning leads to questionable conclusions. A new, correct formula for the intermolecular free length in thermodynamic ideal mixture was derived and discussed in this paper. The free lengths of the components in a thermodynamic ideal mixture are additive in a new “internal surface fraction” concentration scale. Examples illustrated significant differences between the deviations calculated from the two formulae for model systems and real binary mixtures. Since the values of the intermolecular free length deviations and the excess volumes have the same sign, the conclusions about intermolecular interactions based on these functions will be the same.
The analysis of aroma/flavor compounds in green tea using ice concentration linked with extractive stirrer
2017, Journal of Chromatography A
Citation Excerpt :
Although pyrazine derivatives are used as food additives, some medicinal research proved these compounds to have pharmacological actions. For example, methyl pyrazine has a beneficial pharmacological effect, especially for tuberculosis [40,41]. Phenylethyl alcohol is also an effective inhibiting agent for Gram-negative bacteria [42].
Worldwide, green tea is one of the most popular beverages. It promotes blood circulation, liver function, and lowers the risk of cancer and cardiovascular diseases. This drink is characterized by the distinctive odors and flavors produced by its constituent compounds, with its value predicated on the amount and type of constituents extracted from the tea leaves during brewing. Ice concentration linked with extractive stirrer (ICECLES) is a novel sample preparation technique, especially applicable for the extraction of relatively polar compounds while retaining excellent extraction efficiencies for non-polar compounds. In this study, ICECLES was used to prepare green tea for analysis of aroma/flavor compounds by gas chromatography-mass spectrometry (GC–MS). ICECLES performed very well, revealing 301 constituents as compared to 245 for SBSE (i.e., 56 more constituents were detected via ICECLES). Moreover, ICECLES produced stronger signal to noise ratios for all except 4 of 301 constituents, with a maximum signal enhancement of 19. Of the constituents which were only detectable using ICECLES, some very important aroma/flavor and/or medicinal compounds were easily identified, including furfural, furfural alcohol, maltol, eugenol, 2-methylpyrazine, phenethyl alcohol, 2,6-dimethoxyphenol, and α-terpineol. Overall, we confirmed that ICECLES sample preparation followed by GC–MS consistently allowed more complete green tea aroma/flavor analysis, especially for relatively polar compounds, some of which are critical for flavor quality.
A new theoretical model for predicting the solubility of solid solutes in different solvents
2016, Fluid Phase Equilibria
Citation Excerpt :
We have examined this model for Vapor–Liquid Equilibrium calculation of ethyl acetate (1) + ethanol (2) system [28] at T = 333.15 K and n-hexane (1) + ethyl acetate (2) system [29] at T = 353.15 K, and made comparison of Activity Coefficient and Gibbs-Duhem Term from this model and UNIFAC for the two systems, as shown in Tables 5a, 5b, 6 and Fig. 2, Fig. 3. For the Isothermal VLE of n-hexane (1) + ethyl acetate (2) system, no experimental pressure data was reported in Refs. [29], therefore no comparison was made between the calculated and experimental pressure data for this system. The average absolute value of relative deviation between the predicted value of equilibrium vapor phase mole fraction by this model and experimental data are 2.95% and 6.08% for the two system correspondingly, the percentage error for UNIFAC method are 2.98% and 6.19% correspondingly; the average absolute value of relative deviation between the calculated value of activity coefficient by this model and UNIFAC for γ1 and γ2 in ethyl acetate (1) + ethanol (2) system are 2.47% and 2.07% correspondingly, the percentage error for γ1 and γ2 in n-hexane (1) + ethyl acetate (2) system are 0.77% and 0.68% correspondingly; which indicates that this activity coefficient model is reliable for VLE calculations.
We present a new theoretical solubility model, which uses the statistical mechanical expression of activity coefficient and an estimation equation of molar intermolecular potential energy for species in fluid mixtures. The model equation of molar intermolecular potential energy consists of non-polar (van der Walls), electrostatic and hydrogen bonding interaction terms. The average accuracy of the model in correlating the molar intermolecular potential energy of pure species (30 solvents, 10 temperature points for each solvent) is 6.6%. We have examined this model for the solubility of 15 solutes in 36 different solvents (85 systems, 302 data points) over a temperature range of 268.15–402.4 K and a wide solubility range of 10⁻⁷−10⁻¹ (mole fraction scale); the overall average relative error in predicted solubility (302 data points) is 17.384%; which shows that this method is reliable for the prediction of solute solubility in various solvents.
Isothermal vapor-liquid equilibria and excess molar enthalpy of 2-methylpyrazine (2MP) containing binary mixtures. Comparison with DISQUAC predictions
2015, Fluid Phase Equilibria
Citation Excerpt :
Thus, the 2-methylpyrazine is used in food flavors and baccy. This molecule which is an intermediate for aldinamide and hydragogue has several commercial applications, such as in the synthesis of antituberculosis drug [5,6]. Despite their structural and electronic similarity to benzene and pyridine, few experimental thermodynamic studies are reported in the open literature for pyrazines and derivatves.
The vapour pressures of binary mixtures 2-methylpyridine with cyclohexane, n-heptane or toluene were measured by a static method in the range from 263.15 to 353.15 K. The pure components vapour pressures data and those of the mixtures were correlated with the Antoine equation. The excess enthalpies were measured at 303.15 K, by means of an isothermal calorimeter (C80 SETARAM model). The molar excess Gibbs energies, calculated from the vapour–liquid equilibrium data and the molar excess enthalpies compared satisfactorily with group contribution model (DISQUAC).
Qualitative screening and quantitative determination of pesticides and contaminants in animal feed using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry
2008, Journal of Chromatography A
A method has been developed for the target analysis of over 100 pesticides and contaminants in a complex feed matrix. The method is based on extraction with ethyl acetate, cleanup by gel permeation chromatography (GPC) and dispersive solid-phase extraction (SPE) with primary secondary amine phase (PSA), and analysis by comprehensive two-dimensional gas chromatography with full scan time-of-flight mass spectrometric detection (GC × GC–TOF-MS). Parameters studied during method development included a dispersive SPE cleanup step after GPC, large volume injection into the GC system and the GC × GC separation. Qualitative and quantitative performance of the GC × GC system was evaluated by analyzing spiked extracts in the range equivalent to 1–100 μg/kg in feed. At levels of 50 μg/kg and higher, all compounds targeted for could be identified fully automatically by the software based on their mass spectra. At lower levels the hit rate decreased with the concentration. System linearity was excellent in solvent and only slightly affected by matrix (correlation coefficients r ≥ 0.995 for 90% of the compounds). Limits of quantification were in the 1–20 μg/kg range for most compounds. The overall method was validated for 106 compounds at the 10 and 100 μg/kg level. Recoveries between 70% and 110% and RSDs below 20% were obtained for the majority of the compounds.
Thermodynamic Behavior of the (Methylcyclopentane + Ethyl Acetate) Binary Liquid Mixture: Density at Several Temperatures and Vapor-Liquid Equilibrium at 25, 50, and 101.3 kPa
2024, Journal of Chemical and Engineering Data

View all citing articles on Scopus

View full text

Isothermal vapor–liquid equilibria and excess molar volumes for the ternary mixtures containing 2-methyl pyrazine

Abstract

Introduction

Section snippets

Materials

Isothermal VLE

Conclusion

Acknowledgements

Thermochim. Acta

Fluid Phase Equilib.

Fluid Phase Equilib.

J. Chem. Thermodyn.

Can. J. Chem.