Vapor–liquid equilibria for nitrogen with 2-hexanol, 2-heptanol, or 2-octanol binary systems

doi:10.1016/j.fluid.2006.08.005

Fluid Phase Equilibria

Volume 248, Issue 2, 20 October 2006, Pages 168-173

https://doi.org/10.1016/j.fluid.2006.08.005 Get rights and content

Abstract

Isothermal vapor–liquid equilibrium (VLE) data were measured for the binary systems of nitrogen with 2-hexanol, 2-heptanol, or 2-octanol at temperatures from 333.15 to 393.15 K and pressure up to 100 bar. Henry's constants of nitrogen in these three sec-alcohols were determined by using the Krichevesky–Ilinskaya equation. The experimental VLE data were also correlated by the Peng–Robinson and the Patel–Teja equations of state with various mixing rules.

Introduction

Although some VLE data have been reported by previous investigators for the mixtures of nitrogen + 1-propanol [1], [2], [3], [4], [5], nitrogen + 1-butanol [1], [2], [3], [6], [7], [8], nitrogen + 1-pentanol, nitrogen + 1-hexanol, and nitrogen + 1-heptanol [1], [2], and nitrogen + 1-octanol [1], [2], [9], most of the measurements were made at near the ambient conditions and nitrogen + 1-octanol [10] at high temperatures and pressures. No literature data were found in the nitrogen + sec-alcohol systems and at the comparable conditions except our previous article [11], the nitrogen + 2-propanol, nitrogen + 2-butanol, and nitrogen + 2-pentanol systems. In this article, the vapor–liquid equilibrium data were measured for three asymmetric binary mixtures of nitrogen with 2-hexanol, 2-heptanol, or 2-octanol in a temperature range of 333.15–393.15 K and pressures up to 100 bar. These VLE data were also employed to determine Henry's constant of nitrogen in the sec-alcohols and to test various cubic equations of state and mixing rules. The new experimental data of these sec-alcohol-containing systems provide a basis to compare with those of 1-alkanol-containing systems and may also be useful in the determination or the verification of the group interaction parameters involving a –OH group at the secondary position for group-contribution based thermodynamic models.

Section snippets

Experimental section

A semi-flow VLE apparatus was used in this work. The apparatus and the operation procedure have been described by Lee and Chen [12] and Lee and Chao [13]. The equilibrium cell was immersed into an oil thermostated bath (Model EX-251HT, stability = 0.03 K, Neslab Co., USA) and the equilibrium temperature was measured by a micro-thermometer (model 1506, Hart Scientific, USA) with a platinum RTD probe to an uncertainty of ±0.02 K. The fluctuation of pressure was regulated within ±0.1 bar during the

Experimental results

The equilibrium phase compositions as well as the equilibrium vaporization ratios (K_i = y_i/x_i) for nitrogen + 2-hexanol, nitrogen + 2-heptanol, and nitrogen + 2-octanol are listed in Table 1, Table 2, Table 3, respectively. In those three binary systems, the saturated vapor compositions of the sec-alcohols (y₂) increase with increasing temperature and decrease with increasing pressure within the investigated conditions. Fig. 1 shows that y₂ can be correlated with the molar density of nitrogen $(ρ_{N_{2}})$ by

Data reduction with cubic equations of state

The new VLE data were correlated by the Peng–Robinson [19] and the Patel–Teja [14] equations of state with various mixing rules. The mixture constants a_m, b_m and c_m were calculated from $θ_{m} = \sum_{i = 1}^{2} \sum_{j = 1}^{2} x_{i} x_{j} θ_{i j}$

The combining rule of c_ij for the Patel–Teja equation was given by $c_{i j} = \frac{c_{i} + c_{j}}{2}$

Three types of combining rules were employed to calculate a_ij and b_ij. The combining rules for a_ij and b_ij in mixing rule A (one-fluid, one-parameter van der Waals mixing rule) were defined as follows: $a_{i j} = (1 - k_{a_{i j}}) (a_{i} a_{j})$

Conclusion

The vapor–liquid equilibrium data were determined experimentally for three binary systems of nitrogen with 2-hexanol, 2-heptanol or 2-octanol at temperatures from 333.15 to 393.15 K and pressures up to 100 bar. The saturated vapor-compositions of the sec-alcohols could be correlated with the molar density of nitrogen within the entire investigated conditions. The study also found that nitrogen solubilities in the sec-alcohols increased with increasing temperature and Henry's constants of the

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In the following, we summarize some points that are important for experimental methods for phase equilbrium measurement. Almost 800 articles with experimental data on high pressure phase equilibria were found [163–818]. More than 2400 systems have been investigated, from pure-components, binary systems up to complex mixtures with many components.
A review of systems is given, for which experimental high-pressure phase-equilibrium data were published in the period between 2005 and 2008, continuing a series of reviews. To find candidates for articles that are of interest for this survey a three-stage search strategy was used including a systematic search of the contents of the 17 most important journals of the field. Experimental methods for the investigation of high-pressure phase equilibria were classified, described and illustrated using examples from articles of the period between 2005 and 2008. For the systems investigated, the reference, the temperature and pressure range of the data, and the experimental method used for the measurements is given in 54 tables. Vapor–liquid equilibria, liquid–liquid equilibria, vapor–liquid–liquid equilibria, solid–liquid equilibria, solid–vapor equilibria, solid–vapor–liquid equilibria, critical points, the solubility of high-boiling substances in supercritical fluids, the solubility of gases in liquids and the solubility (sorption) of volatile components in polymers are included. Most of experimental data in the literature has been given for binary systems. Of the 1469 binary systems, 796 (54%) have carbon dioxide as one of the components. Information on 206 pure components, 535 ternary systems of which 355 (66%) contain carbon dioxide, 163 multicomponent and complex systems, and 207 systems with hydrates is given. A continuation of the review series is planned, covering the years from 2009 to 2011.
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Vapor–liquid equilibria for nitrogen with 2-hexanol, 2-heptanol, or 2-octanol binary systems

Abstract

Introduction

Section snippets

Experimental section

Experimental results

Data reduction with cubic equations of state

Conclusion

Fluid Phase Equilib.

Fluid Phase Equilib.

J. Chem. Thermodyn.

Fluid Phase Equilib.

Fluid Phase Equilib.

Fluid Phase Equilib.

Fluid Phase Equilib.

Chem. Eng. Sci.

Fluid Phase Equilib.

J. Phys. Chem.

J. Chem. Eng. Data