Characterizing Isoparaffin Transport Properties with Stokes-Einstein Relationships

P. A. Gordon, Industrial and Engineering Chemistry Research, 42, 7025-7036, (2003).

We present extensive molecular dynamics simulation results for self-diffusion and viscosity for isoparaffins between Ce and C 16 and examine the ability of several forms of Stokes-Einstein relationships to link the transport properties in a coherent framework. Based on a hydrodynamic model for drag past prolate ellipsoids in the slip limit, much of the variation between diffusion and viscosity can be explained as a function of molecular structure. For pure species, we demonstrate how one can exploit the linearity of the Stokes-Einstein relationship to make quantitative, extrapolative predictions of viscosity from computer simulations based on the self-diffusion coefficient and systematic characterization of the molecule's gyration ellipsoid.

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