Mutual diffusion in the ternary mixture of water + methanol + ethanol and its binary subsystems

Abstract

Mutual diffusion is investigated by means of experiment and molecular simulation for liquid mixtures containing water + methanol + ethanol. The Fick diffusion coefficient is measured by Taylor dispersion as a function of composition for all three binary subsystems under ambient conditions. For the aqueous systems, these data compare well with literature values. In the case of methanol + ethanol, experimental measurements of the Fick diffusion coefficient are presented for the first time. The Maxwell-Stefan diffusion coefficient and the thermodynamic factor are predicted for the ternary mixture as well as its binary subsystems by molecular simulation in a consistent manner. The resulting Fick diffusion coefficient is compared to present measurements and that obtained from the classical simulation approach, which requires experimental vapor-liquid equilibrium or excess enthalpy data. Moreover, the self-diffusion coefficients and the shear viscosity are predicted by molecular dynamics and are favorably compared to experimental literature values. The presented ternary diffusion data should facilitate the development of aggregated predictive models for diffusion coefficients of polar and hydrogen-bonding systems.

Investigation of Fickian diffusion in the ternary mixtures of water–ethanol–triethylene glycol and its binary pairs

“…Table 5 and Fig. Again, the values calculated by the Stokes-Einstein Table 1 Parameters of liquids used for the calculation of tracer diffusion coefficients according to eqn (26) and (28 10 Hammond (diaphragm cell), 39 Harris (Taylor dispersion), 40 Kolodner (OBD), 41 and Wiegand (thermal diffusion forced Rayleigh scattering). Again, the values calculated by the Stokes-Einstein Table 1 Parameters of liquids used for the calculation of tracer diffusion coefficients according to eqn (26) and (28 10 Hammond (diaphragm cell), 39 Harris (Taylor dispersion), 40 Kolodner (OBD), 41 and Wiegand (thermal diffusion forced Rayleigh scattering).…”

A reverse nonequilibrium molecular dynamics method for calculating the mutual diffusion coefficient for binary fluids

“…MD simulation is a good choice when experiments are impossible, unfeasible or simply too expensive (Cussler, 2009). Many equilibrium MD simulations have been performed to calculate self-and mutual diffusion coefficients for two or three component systems (for example: Jolly and Bearman, 1980;Schoen and Hoheisel, 1984;MacGowan, 1986;Hoheisel and Vogelsang, 1988;Pas and Zwolinski, 1991;van de Ven-lucassen et al, 1999;Min et al, 2007;Liu et al, 2011;Schnell et al, 2011;Pařez et al, 2013). Liu et al (2013) reviewed the methods for predicting mutual diffusion coefficients from MD simulations, recently.…”

A re-appraisal of the concept of ideal mixtures through a computer simulation study of the methanol-ethanol mixtures

“…Since methanol and ethanol are very similar, differing only by a single methyl group, one expects their mixtures would be ideal. The query about the ideality of this type of mixture has been recently asked in a study 3 of the diffusion constants in mixtures, where the near absence of concentration fluctuations was pointed out. Indeed, the excess energy of the mixture is almost zero, very much like that of the Lennard-Jones mixture tailored over the respective molecular sizes.…”