Viscosity and Surface Tension of Branched Alkanes 2-Methylnonane and 4-Methylnonane

Klein, Tobias; Cui, Junwei; Kalantar, Ahmad; Chen, Jiaqi; Rausch, Michael H.; Koller, Thomas M.; Fröba, Andreas P.

doi:10.1021/acs.jced.8b00163

Cited by 16 publications

(16 citation statements)

References 15 publications

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“…These properties are then used to determine the viscosity and interfacial tension of the liquid. For a detailed discussion of the relevant theory ,,,, and its application within thermophysical property research, − ,,− the reader is referred to the literature. The experimental setup and the measurement procedure and conditions are the same as in our previous studies. , In this work, only relevant information on the principles of the technique and the data evaluation is provided.…”

Section: Experimental Sectionmentioning

confidence: 99%

Viscosity, Interfacial Tension, and Density of Binary-Liquid Mixtures of n-Hexadecane with n-Octacosane, 2,2,4,4,6,8,8-Heptamethylnonane, or 1-Hexadecanol at Temperatures between 298.15 and 573.15 K by Surface Light Scattering and Equilibrium Molecular Dynamics Simulations

et al. 2021

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This work contributes to the characterization of three binary liquid hydrocarbon-based mixtures via the determination of density, viscosity, and interfacial tension over the entire concentration range up to temperatures of 573.15 K. The oscillating-tube method, surface light scattering (SLS), and equilibrium molecular dynamics (EMD) simulations are applied to analyze the influences of chain length, branching, and hydroxylation on the aforementioned thermophysical properties. For probing these effects, the three binary systems of n-hexadecane (1) with n-octacosane (2), 1-hexadecanol (2), or 2,2,4,4,6,8,8-heptamethylnonane (2), each with mole fraction of x 1 = 0.25, 0.5, or 0.75, are investigated in macroscopic thermodynamic equilibrium at or close to saturation conditions at temperatures between 298.15 and 573.15 K. Based on the experimental results for the liquid densities, liquid viscosities, and interfacial tensions with average expanded uncertainties (k = 2) of 0.10, 2.0, and 1.8%, respectively, our previously published modification to the optimized potentials for the liquid simulations (OPLS) force field for long hydrocarbons (L-OPLS) is evaluated for its transferability to liquid mixtures in EMD simulations. Considering all simulation results, the average absolute relative deviations for the density, viscosity, and interfacial tension are 0.74, 27, and 14%, respectively. Experimental results are also applied for the evaluation of simple prediction models based on pure-component properties. Especially at high temperatures, such simple mixing rules perform well. At lower temperatures, however, nonidealities like surface enrichment or the formation of molecule clusters in the mixture are more likely to dominate fluid behavior, leading to a failure of the simple mixing rules. To explain this observation, partial-density profiles and radial distribution functions from simulations, giving access to the fluid structure on a microscopic level, are evaluated.

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Section: Experimental Sectionmentioning

confidence: 99%

Viscosity, Interfacial Tension, and Density of Binary-Liquid Mixtures of n-Hexadecane with n-Octacosane, 2,2,4,4,6,8,8-Heptamethylnonane, or 1-Hexadecanol at Temperatures between 298.15 and 573.15 K by Surface Light Scattering and Equilibrium Molecular Dynamics Simulations

et al. 2021

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“…With the latter, the dynamics of surface fluctuations at phase boundaries is studied in a contactless manner via the analysis of the temporal behavior of the intensity of the scattered light. On the basis of the full description of the hydrodynamic theory for the probed surface fluctuations, , viscosity and interfacial tension of various fluid types including reference fluids − and liquids with dissolved gases could be determined by SLS in an absolute way with typical uncertainties of 2% (coverage factor k = 2) up to 573.15 K. For an accurate determination of viscosity and interfacial tension of two-phase vapor–liquid systems from SLS experiments, input parameters in the form of the density and viscosity of the vapor phase, which can be estimated by the corresponding prediction schemes, and the density of the liquid phase are required. For the latter, measurements with a vibrating tube densimeter can be combined with the isochoric-saturation method to obtain further information about the solubility of the dissolved gas in the liquid phase …”

Section: Introductionmentioning

confidence: 99%

Viscosity and Interfacial Tension of Binary Mixtures of n-Hexadecane with Dissolved Gases Using Surface Light Scattering and Equilibrium Molecular Dynamics Simulations

et al. 2021

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In the present study, the influence of dissolved gases on the viscosity and interfacial tension of n-hexadecane is investigated using surface light scattering (SLS) experiments and equilibrium molecular dynamics (EMD) simulations. In detail, binary mixtures of n-hexadecane with the solutes hydrogen, helium, methane, water, nitrogen, carbon monoxide, and carbon dioxide are studied in the temperature range between (298 and 573) K and for two solute mole fractions up to 0.2. With SLS, the liquid viscosity and interfacial tension of the binary mixtures were accessed with average expanded uncertainties (coverage factor k = 2) of 2.3 and 1.9%, respectively. By comparing the thermophysical properties of the binary mixtures with the ones of pure n-hexadecane, the influence of the dissolved gases is discussed. For the two lightest gases hydrogen and helium as well as for the solute water, only a small influence of the dissolved gas could be found. For the other gases, a decrease of up to 30% is found for both the viscosity and interfacial tension. While the results for the interfacial tension of the binary mixtures from EMD simulations agree well with the results from SLS measurements, the simulations fail to predict the influence of the dissolved gas on the viscosity accurately. Finally, the enrichment of the solute molecules at the vapor−liquid interface analyzed using EMD simulations is linked to the interfacial tension results.

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“…For these mixtures, the interfacial tension is approximately 25% lower than the surface tension of pure n-C 28 H 58 for the various temperatures studied. At the lowest temperature of 398.15 K, the σ value of the mixture containing 4methylnonane is only 14% smaller than that of pure 4methylnonane, 14 but 27% larger than that of pure noctacosane 15 despite the very small mole fraction of 4methylnonane in the liquid phase of 0.026. With increasing temperature, the interfacial tension of the mixtures containing the branched alkanes tends more and more toward the surface tension of pure n-C 28 H 58 .…”

Section: ■ Results and Discussionmentioning

confidence: 88%

“…The σ values for the binary mixtures are close to the values for the pure branched alkanes. 14 This behavior may be caused by an enrichment of the branched alkanes at the vapor−liquid interface, which promotes the reduction of the surface free energy and, thus, of the interfacial tension. The enrichment seems to be related to the relatively weak intermolecular interactions between the branched alkanes with their sterical bulkiness and the linear n-C 28 H 58 which are distinctly smaller than those between the two linear n-alkanes n-decane and n-C 28 H 58 .…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Liquid Viscosity and Interfacial Tension of Binary and Ternary Mixtures Containing n-Octacosane by Surface Light Scattering

et al. 2019

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In this study, the liquid viscosity and interfacial tension of binary and ternary mixtures containing noctacosane (n-C 28 H 58 ) and different byproducts typically found in the Fischer−Tropsch process were investigated. For the binary mixtures having mole fractions of the byproducts between 0.02 and 0.40, the effects of varying branching, alkyl chain length, and degree of oxygenation in selected byproducts on viscosity and interfacial tension were studied. In detail, the isomers n-decane, 2-methylnonane, and 4-methylnonane were used to study differences in branching for alkanes with the same molecular weight. The 1-alcohols ethanol and 1-dodecanol as well as the carboxylic acids formic acid and acetic acid imply variations in the alkyl chain length and degree of oxygenation. In addition, two ternary systems consisting of n-octacosane, n-decane, and ethanol with mole fractions of 0.6 of either n-alkane and 0.2 for each of the other two components were selected. On the basis of the surface light scattering (SLS) method analyzing microscopic surface fluctuations at macroscopic thermodynamic equilibrium, the liquid viscosity and interfacial tension of the studied mixtures could be determined at saturation conditions at temperatures from (373.15 up to 523.15) K with average expanded measurement uncertainties (k = 2) of (2.7 and 2.4)%. Except for systems containing the two branched alkanes showing a distinct decrease in the interfacial tension even at low mole fractions of 0.025, liquid viscosity and interfacial tension at 423 K are not strongly affected with increasing concentration of the byproducts up to 0.10 compared to the values for pure n-octacosane within relative deviations of 10% and 5%. For the studied binary and ternary systems, simple mixing rules for liquid viscosity and interfacial tension based on the corresponding properties of the pure components are discussed.

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Viscosity and Surface Tension of Branched Alkanes 2-Methylnonane and 4-Methylnonane

Cited by 16 publications

References 15 publications

Viscosity, Interfacial Tension, and Density of Binary-Liquid Mixtures of n-Hexadecane with n-Octacosane, 2,2,4,4,6,8,8-Heptamethylnonane, or 1-Hexadecanol at Temperatures between 298.15 and 573.15 K by Surface Light Scattering and Equilibrium Molecular Dynamics Simulations

Viscosity, Interfacial Tension, and Density of Binary-Liquid Mixtures of n-Hexadecane with n-Octacosane, 2,2,4,4,6,8,8-Heptamethylnonane, or 1-Hexadecanol at Temperatures between 298.15 and 573.15 K by Surface Light Scattering and Equilibrium Molecular Dynamics Simulations

Viscosity and Interfacial Tension of Binary Mixtures of n-Hexadecane with Dissolved Gases Using Surface Light Scattering and Equilibrium Molecular Dynamics Simulations

Liquid Viscosity and Interfacial Tension of Binary and Ternary Mixtures Containing n-Octacosane by Surface Light Scattering

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