Tracer diffusion in methanol and acetonitrile under pressure

Abstract

Tracer-diffusion measurements have been made with a diaphragm cell at pressures up to ca. 260 MPa for acetonitrile in methanol and methanol in acetonitrile at 283, 298 and 313 K and up to 300 MPa for carbon disulphide in acetonitrile at 298 K. A correlation treatment used previously for self-diffusion in pure fluids has been extended to cover this type of tracer diffusion. Analysis of the data in acetonitrile indicates that dipole–dipole interactions between the tracer species and solvent may have a significant effect on the diffusion.