Capillary constant and surface tension of dimethyl ether and n-butane at temperatures from 214 K to those close to the critical point
Introduction
In recent years, dimethyl ether and n-butane have been widely used in motor transport as fuels. Due to its high cetane number, lowered liability to soot formation during combustion, and almost no smoking at the exhaust, ether is regarded as an alternative to the traditional diesel fuel in future [1]. The boiling point of normal butane is higher than that for liquefied natural gas, so it is used in motor transport and household applications in mixture with propane and other hydrocarbons. As raw materials, dimethyl ether and n-butane are used in the processes of catalytic cracking and pyrolysis, in the manufacture of high – octane petrol and the production of synthetic rubber, and as propellants in deodorants, aerosol spray–on paints, etc.
For practical applications of dimethyl ether and n-butane reliable data on their physicochemical properties, in particular, on their surface tension are required. These data are necessary for studies of the character of fuel spray, boiling, condensation, and capillary phenomena.
This paper presents the results of our measurements of the capillary constant а2 and calculations of the surface tension σ of dimethyl ether at temperatures from 214 K, and those of n-butane from 278.15 K to temperatures near their critical points. All in all, 35 values of the capillary constant for dimethyl ether and 40 values of а2 for n-butane have been obtained. The surface tension of dimethyl ether was measured before by Maas and Boomer [2] (15 points, 231–263 К), Winkler and Maas [3] (6 points, 375.65–398.15 К), Soares et al. [4] (10 points, 131.7–139.1 К), Wu et al. [5] (31 points, 213–368 К). Experiments with n-butane were conducted before by Coffin and Maas [6] (19 points, 138.75–305.65 K), Reno and Katz [7] (1 point, 298.15 K), Katz and Saltman [8] (14 points, 275.2–318.5 K), Calado, McLure and Soares [9] (6 points, 238.0–273.3 K). The surface tensions of dimethyl ether [10] and n-butane [11] were measured before in our laboratory from the triple point temperature to 214 and 282.27 K, correspondingly.
Section snippets
Materials
A sample of dimethyl ether (methoxymethane, RE170, C2H6O, M = 46.0684 g/mol) was provided by Sigma–Aldrich (Germany), and a sample of n-butane (methylethylmethane, C4H10, M = 58.1222 g/mol) by VNIIGAZ (Russia). Details of the samples are presented in Table 1. In the experiments, use was made of substances from the same lots on which measurements of σ at low temperatures were previously conducted.
Apparatus and technique
The surface tension of dimethyl ether and n-butane was measured by the differential capillary-rise
Results
The surface tension of dimethyl ether was measured along the liquid–gas equilibrium coexistence curve in the temperature range 214–390, for n-butane – in the temperature range 278.15–423.04 K. The average values of a2 for 5–10 measurements of Δhij are listed in Table 2. In addition, the values of ρl and ρg from Ref. [19] [20], used in calculations of the surface tension are presented.
In the range from the triple to the critical point the temperature dependence of the capillary constant a2 was
Conclusion
Thus, in the present work and in our earlier work [10], [11] experimental data on the surface tension of dimethyl ether and n-butane were obtained with uniform measuring tools in the temperature range from the triple point to temperatures near the critical point.
All in all, the temperature range investigated with the exception of near-critical values of the uncertainty of the data obtained does not exceed 0.010 mN/m.
Within this error the result of measuring the surface tension of dimethyl ether
Acknowledgements
This study was financially supported by the Russian Foundation for Basic Research (project no. 15-08-03399-a), the complex program of basic research of the Ural Branch of the Russian Academy of Science (project no. 15-1-2-6) in the case of dimethyl ether. Measurements of the surface tension of n-butane were conducted in the framework of project no. 14-19-00567 of the Russian Scientific Foundation.
References (28)
- et al.
Surface tension of pure and mixed substances at low temperatures
Fluid Phase Equilib.
(1986) - et al.
Surface tension for octafluorocyclobutane, n-butane and their mixtures from 233 to 254 K, and vapour pressure, excess Gibbs function and excess volume for mixture at 233 K
Fluid Phase Equilib.
(1978) - et al.
Capillary constant and surface tension of methane–nitrogen solutions: 1. Experiment
Fluid Phase Equilib.
(2011) - et al.
Surface tension of an ethane–nitrogen solution. 1: Experiment and thermodynamic analysis of the results
Fluid Phase Equilib.
(2012) - et al.
Capillary constant and surface tension of methane–helium solution
Fluid Phase Equilib.
(2013) - et al.
Surface tension of ethane–methane solutions: 1. Experiment and thermodynamic analysis of the results
Fluid Phase Equilib.
(2013) Correction terms for calculating surface tension from capillary rise
J. Colloid Interface Sci.
(1973)- et al.
Experimental densities, vapor pressures, and critical point, and a fundamental equation of state for dimethyl ether
Fluid Phase Equilib.
(2007) Fluid mixtures at high pressures VI. Phase separation and critical phenomena in 18 (n-alkane + ammonia) and 4 (n-alkane + methanol) mixtures
J. Chem. Thermodyn.
(1988)- et al.
Study on the performance and emissions of a compression ignition engine fuelled with dimethyl ether
Proc. Inst. Mech. Eng. Part D
(2000)
Vapor densities at low pressures and over an extended temperature range. I. The properties of ethylene oxide compared to oxygen compounds of similar molecular weight
J. Am. Chem. Soc.
An investigation of the surface tension of liquids near the critical temperature
Can. J. Res.
Surface tension of dimethyl ether from (213 to 368) K
J. Chem. Eng. Data
The preparation and physical properties of α-, β- and γ-butylene and normal and isobutane
J. Am. Chem. Soc.
Cited by (6)
Capillary constant and surface tension of hydrogen and helium solutions in n-butane (R600)
2023, Fluid Phase EquilibriaCapillary constant and surface tension of liquefied gases saturated with helium
2019, Fluid Phase EquilibriaSpontaneous cavitation in liquid n-butane at negative and positive pressures
2017, International Journal of Heat and Mass TransferCitation Excerpt :In calculations of the main parameters of the nucleation process we used the data on the thermophysical properties of n-butane from Ref. [20]. Information on the surface tension of n-butane has been taken from Ref. [22]. The main reason for the discrepancy between stretchings achieved by experiment and their theoretical values is evidently the fact that classical nucleation theory does not take into account the size dependence of the surface tension of critical bubbles.
Recommended Correlations for the Surface Tension of Ethers
2023, Journal of Physical and Chemical Reference DataRecommended Correlations for the Surface Tension of n-Alkanes
2021, Journal of Physical and Chemical Reference DataAttainable superheating of liquid n -butane
2018, Physics of Fluids