Benchmark values for the Soret, thermal diffusion and diffusion coefficients of three binary organic liquid mixtures

Section: Introductionmentioning

confidence: 99%

Experimental investigation of the Soret effect in acetone/water and dimethylsulfoxide/water mixtures

Ning

Wiegand²

2006

“…14,15 For this reason, the Benchmark of Fontainebleau was performed, 14 where several laboratories carried out a quantitative comparison between different experimental methods actively used in [1999][2000][2001][2002][2003] to determine the diffusion, thermal diffusion, and Soret coefficients of three binary liquid mixtures. The Benchmark is still in progress as recently the results from beam deflection technique have been introduced to the benchmark 13 and some actively used methods have not yet contributed into Benchmark database.…”

Section: Introductionmentioning

confidence: 99%

Measurement of the Soret and diffusion coefficients for benchmark binary mixtures by means of digital interferometry

Mialdun

Shevtsova

2011

102

We report on the development of the optical digital interferometry (ODI) technique for measuring diffusion and Soret coefficients. The unique feature of this method is that it traces the transient path of the system in the entire two-dimensional cross section of a cell. In this way, it is applicable not only for measurements of Soret coefficients, but also for studying diffusive transport mechanism and convection. Presently, this method is not widely used and, in our view, not because of fundamental limitations but rather due to a lack of properly developed postexperimental procedures of the raw data analysis. Thus, in this paper our attention is focused on the successive analysis of different steps: the fringe analysis, the choice of reference images, the thermal design of the cell, and multiparameter fitting procedure. Using the ODI technique, we have measured the diffusion and the Soret coefficients for three binary mixtures composed of dodecane (C 12 H 26 ), isobutylbenzene, and 1,2,3,4-tetrahydronaphtalene at a mean temperature of 25 • C and 50 wt. % in each component. These measurements were compared with their benchmark values and show an agreement within less than 3%.

“…The choice of the particular model binary mixture to study has been mainly driven by the need of having a mixture which is already well characterized at atmospheric pressure, 28 and which also provides a strong Soret effect. On this basis the liquid mixture has been chosen as 1,2,3,4-tetrahydronaphtalene (THN)-n-dodecane (n-C12) kept at a constant temperature T mean = 25 • C.…”

Section: Introductionmentioning

confidence: 99%

Concentration dependent refractive index of a binary mixture at high pressure

Croccolo

Arnaud

Bégué

et al. 2011

In the present work binary mixtures of varying concentrations of two miscible hydrocarbons, 1,2,3,4-tetrahydronaphtalene (THN) and n-dodecane (C12), are subjected to increasing pressure up to 50 MPa in order to investigate the dependence of the so-called concentration contrast factor (CF), i.e., (∂n/∂c) p,T , on pressure level. The refractive index is measured by means of a Mach-Zehnder interferometer. The setup and experimental procedure are validated with different pure fluids in the same pressure range. The refractive index of the THN-C12 mixture is found to vary both over pressure and concentration, and the concentration CF is found to exponentially decrease as the pressure is increased. The measured values of the refractive index and the concentration CFs are compared with values obtained by two different theoretical predictions, the well-known Lorentz-Lorenz formula and an alternative one proposed by Looyenga. While the measured refractive indices agree very well with predictions given by Looyenga, the measured concentration CFs show deviations from the latter of the order of 6% and more than the double from the Lorentz-Lorenz predictions.