Studies on self-diffusion of main components of hop oils

The self-diffusion coefficients (D) of alpha -humulene and myrcene, which a re main components of hop oils, were measured at the temperature range of 2 74-372 K and pressures up to 100 MPa by the Stejskal-Tanner ET NMR method. In order to obtain motional behavior of the molecules in the supercritical conditions, the intradiffusion coefficients (D-ii) of the two substances in carbon dioxide were also determined. It was found that the values of D-ii are about one order of magnitude higher than that for the pure components a t the same ranges of temperature and pressure. The self-diffusion data of a lpha -humulene and myrcene are analysed, and the diffusion behavior of thes e compounds is discussed.