Temperature and Pressure Dependence of Self Diffusion in Long Liquid n‐Alkanes

A titanium autoclave for the determination of self diffusion coefficients by the pulsed field gradient spin‐echo method is described, that has been used in the temperature range between 200 and 500 K at pressures up to 600 MPa.—In a first series of experiments, melts of n‐alkanes with chain lengths between 16 and 154 carbon atoms were studied. The data are analyzed with modifications of the hard sphere model and tested against the Rouse‐ and reptation model.