ISSN:
0001-1541
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
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, C6H5X where X = H, F, Cl, Br, and I, n-paraffins, CnHn + 2 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 20°C 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 molecular diameter d (d = 2.24(η VD/RT)1/2) 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 Tr 〈 0.46 shows the invalidity of the Stokes-Einstein relation for this temperature range (Tr = 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.
Additional Material:
10 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aic.690190619
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