The mutual diffusion coefficient of ethanol–water mixtures: determination by a rapid, new method

Abstract

Mutual diffusion coefficients for liquid mixtures of ethanol and water have been measured over the entire range of composition and for temperatures from 25 to 65 °C at a pressure of 1 bar (10 5 Pa). At the lowest temperature, the results establish the validity of a new experimental method based upon Taylor’s analysis of solute dispersion in laminar flow. The method offers advantages of simplicity and speed over other techniques, and allows direct measurement of diffusion coefficients at well-defined mixture compositions. The experimental data have an estimated uncertainty of ±2.5% . The results have been utilized to evaluate friction coefficients arising in the statistical mechanical theory of transport in liquid mixtures.

Measuring concentration fields in microfluidic channels in situ with a Fabry–Perot interferometer

“…The measured values of the dilute diffusivity agree with previously published literature values for all solutes. [33][34][35][36][37][38] Measurements of b agree well with literature values for ethanol and 2-propanol; 34,35 however, they are higher than literature values for glucose, glycerol, and sucrose. 33,[36][37][38] In the literature, the diffusion coefficients are measured with very small chemical gradients centered at different concentrations, while we extract the concentration dependence from a single steep chemical gradient.…”

“…A linear relationship between concentration and diffusivity was assumed based on the solutes and concentration ranges used in the study (eqn (6)). [33][34][35][36][37][38] …”

Bénard instabilities in a binary-liquid layer evaporating into an inert gas

“…To sum up, the formulation of section 2 is modified as follows: (2) is replaced by (78), (8) by (79), (10) by (80) and (81), the third expression (12) by (82), the second condition (14) by (83), (19) by (84), (23) by (86), (24) by (87), (25) by (90), and besides we have to consider (88), (89) and (91).…”

“…In the case of a mass fraction of 0.001, the physical properties are taken to be those of pure water, with the exception of inherently binary-mixture properties such as , / , , and . These are taken for a mass fraction of 0.001 of ethanol in water, found in respectively [33], [24] and [34] (p. 2-112). So these values need no further explanation.…”

“…For instance, this is in the sense that the material properties of the liquid have all been fixed at (section 2), whereas at least some of them are rather sensitive to : these include the diffusion coefficient [24], the Soret coefficient (11) and even -cf. …”