Interfacial Tension and Liquid Viscosity of Binary Mixtures of n-Hexane, n-Decane, or 1-Hexanol with Carbon Dioxide by Molecular Dynamics Simulations and Surface Light Scattering

• Published in: International journal of thermophysics 2019-08, Vol.40 (8), p.1-24, Article 79
• Main Authors: Koller, Thomas M., Yan, Shaomin, Steininger, Corina, Klein, Tobias, Fröba, Andreas P.
• Format: Article
• Language: English
• Subjects: Binary mixtures; Carbon dioxide; Classical Mechanics; Condensed Matter Physics; Geophysics; Hydroxylation; Industrial Chemistry/Chemical Engineering; Light scattering; Liquid phases; Liquid-vapor equilibrium; Molecular dynamics; Physical Chemistry; Physics; Physics and Astronomy; Simulation; Surface tension; Thermodynamics; Viscosity
• ISSN: 0195-928X; 1572-9567
• DOI: 10.1007/s10765-019-2544-y

In the present study, the interfacial tension and liquid viscosity of binary mixtures of n -hexane, n -decane, or 1-hexanol with carbon dioxide (CO 2 ) were investigated by molecular dynamics (MD) simulations and surface light scattering (SLS). The latter technique was applied to study experimentally the influence of dissolved CO 2 on the interfacial tension and liquid viscosity of binary mixtures of n -hexane with CO 2 at 303.15 K and saturation pressures up to 5 MPa corresponding to a CO 2 mole fraction in the liquid phase up to 0.75. For this system at vapor–liquid equilibrium, the liquid viscosity and interfacial tension were determined with average relative expanded uncertainties ( k  = 2) of (1.8 and 1.3) %. In equilibrium MD simulations for binary mixtures of n -hexane, n -decane, or 1-hexanol with CO 2 , the vapor–liquid equilibria including saturated densities as well as the interfacial tensions were predicted at temperatures of (303.15, 333.15, and 363.15) K for CO 2 mole fractions in the liquid phase up to 0.52. For the binary mixtures of n -hexane with CO 2 , agreement between the measured and simulated data for viscosity and interfacial tension was found. With the three mixtures investigated by MD simulations, the influence of chain length and hydroxylation on the interfacial tension could be demonstrated. The simulations showed that the magnitude of CO 2 enrichment at the vapor–liquid interface is more pronounced for solvents with larger surface tensions.