Self‐diffusion and viscosity of some liquids as a function of temperature

Abstract

Self-diffusion coefficients of 15 liquids have been measured as a function of temperature between their melting and boiling points. The systems investigated were the benzenes, CBH5X where X = H, F, C1, Br, and I, n-paraffins, CnHnfe where n = 7, 9, 10, 12, 14, 16, and 18, acetone, acetic acid and water. The pulsed nmr technique was employed for the diffusion measurements. In addition, the viscosities of the halogenated benzenes have been measured between 2OoC and their melting points.The diffusion results obtained in this study have been found in excellent agreement with the best values available for benzene (Collings and Mills, 1970) and water (Longworth, 1960). The relation between the apparent H. ERTL and F. A. L. DULLIEN molecular diameter d (d = 2.24(7VD/RT)S) and the critical volume as suggested by Dullien (1972) has been extended to include the temperature dependence of d. It is also shown that the temperature dependence of d is similar for all liquids studied here with respect to the reduced temperature. The increase of d for T, < 0.46 shows the invalidity of the Stokes-Einstein relation for this temperature range (T, = T/Tc).A normalized plot of d has been found very useful in checking the consistency of viscosity and self-diffusion data. The relations proposed in this work can be used to predict self-diffusion coefficients and viscosities over the normal liquid range.

Reverse Nonequilibrium Molecular Dynamics Calculation of the Soret Coefficient in Liquid Heptane/Benzene Mixtures

“…larger, respectively than the experimental value 16,23 . The mutual diffusion coefficient for a n-heptane mole fraction of 0.25 is in satisfactory agreement with the experiment, while the other two values (n-heptane mole fraction of 0.5 and 0.75) are systematically ≈ 40% larger than in the experiment.…”

Study of the thermal diffusion behavior of simple binary mixtures

“…larger, respectively than the experimental value [96,49]. The mutual diffusion coefficient for a n-heptane mole fraction of 0.25 is in satisfactory agreement with the experiment, while the other two values (n-heptane mole fraction of 0.5 and 0.75) are systematically ≈ 40% larger than in the experiment.…”

NMR Self-Diffusion Studies of the Water and the Oil Components in a W/O/W Emulsion

“…fitted parameters (see Table 1) is most likely a consequence Table 1 (38). Thus the ratio of the diffusion coefficient of decane or increased in value, depending on the sign of the difference in the emulsion and in the bulk is 0.6.…”