Tracer diffusion in methanol, 1-butanol and 1-octanol from 298 to 433 K



Diffusion coefficients of argon, krypton, xenon, methane, carbon tetrachloride and the tetraalkyltins (methyl through butyl) were measured in methanol, 1-butanol and 1-octanol over the temperature range 298 to 433 K. With temperature-dependent solvent diameters fitted from the tracer diffusivity of one of the solutes, a rough-hard-sphere theory predicts well the observed tracer diffusivity over the solvent density range in which hard-sphere computer simulations are available. The Wilke-Chang correlation predicts diffusion coefficients in the higher alcohols with an average error of 80% and a maximum error of 200%. A correlation of the form Dμp/T = A where p and A depend on solute and solvent size is more successful giving an average error of 7% and a maximum error of 24%.