Determination of thermal diffusion coefficient in equimolar n-alkane mixtures: Empirical correlations

In this article we determined the thermal diffusion coefficient (D-T) in equimolar mixtures of n-alkanes nC(i)-nC(12) (i=5,6,7,8,9,17,18), nC(i)-nC(10) (i=5,6,7,15,16,17,18), and nC(i)-nC(6) (i=10,12,14,16,18) at 25 degrees C and at atmospheric pressure using the thermogravitational technique. The results obtained from this study together with the previously published ones in the series of nC(i)-nC(18) (i=5,6,7,8,9,10,11,12,13) show that the main parameter that determines D-T in each series is in association with the molecular weights of the mixture's components. However, an empirical quantitative correlation has been obtained between D-T, the molecular weights of the components, the viscosity, and the thermal expansion coefficient of the mixtures. This is the first report of a closely accurate correlation for D-T in liquid mixtures.