Thermogravitational Thermal Diffusion. V. Temperature Difference Effects. Thermal Diffusion Factors for the System Carbon Tetrachloride–Cyclohexane and Carbon Tetrachloride–Ethyl Alcohol

Abstract

Thermal diffusion factors calculated according to the revised theory of Horne and Bearman are shown to vary with temperature difference, contrary to theoretical expectations. On the assumption that the variation is due to reservoir effects, it is argued that the results should be extrapolated to zero temperature difference. When this is done, the present data for the carbon tetrachloride–cyclohexane system come into excellent agreement with those of Turner, Butler, and Story, who used a flow-cell technique. Data for the carbon tetrachloride–ethyl alcohol system agree within experimental uncertainties with those of Whitaker and Pigford, who used the pure thermal diffusion technique. It thus appears that three independent techniques will yield the same thermal diffusion factors. Hence, from an empirical standpoint, it would seem that the problem of their measurement has been solved for nonelectrolyte liquid solutions.