Pressure and Temperature Dependence of the Self-diffusion of Benzene

Abstract

The self-diffusion coefficient of liquid benzene has been measured with a modified diaphragm cell. The cell incorporates a bellows in one compartment and the technique for its use makes allowance for bulk flow effects due to changes in pressure. Results have been obtained at 288, 298, 313 and 328 K over the pressure ranges 1-283, 1-645, 1-975 and 1-1496 bar, respectively and used to calculate activation energies and volumes. In contrast to earlier (less accurate) data the present results indicate a non-linear dependence of log D on pressure. The results are used to test a quasi-lattice model of the liquid. The Stokes-Einstein relation is obeyed over only a narrow density range.