Thermal diffusion of diphenyl in benzene and of urea in water

Abstract

The Soret coefficient of diphenyl in benzene has been measured at six concentrations at 25°C and at one concentration at 35°C. The concentration and temperature dependencies of the results are both slight. The Soret coefficient of urea in water at 25°C has been measured at four concentrations, and increases significantly with concentration. The laminar flow-cell method was used, with a Rayleigh interferometer to measure the concentration differences.