Viscosity and self-diffusion in benzene-cyclohexane mixtures

Abstract

The self-diffusion coefficient of benzene in benzene-cyclohexane mixtures was measured at 15�, 25�, and 35�. Viscosities of the mixtures were measured at the same temperatures. The diffusion coefficient is a maximum, while the viscosity is a minimum at a mole fraction of benzene between 0.6 and 0.8. The activation energy for viscous flow is a minimum in the mole fraction range 0.6-0.8 of benzene. The excess viscosity and the excess activation energy of viscous flow are minimal at a mole fraction 0.5, the same composition at which the maxima occur in excess volume and heat mixing. The product Dn is a linear function of mole fraction.