Diffusion in Polymethylene\nChain Solutions with a\nPolar Component

A hydrodynamic bead model based on Kirkwood-Riseman theory\nhas\nbeen used to calculate the translational diffusion constant, <i>D</i>, for solutes with polymethylene chains in solutions with\na polar component. A comparison with the experimental values for nonpolar <i>n</i>-alkanes in polar 2-propanol, tetrahydrofuran, chlorobenzene,\nchloroform, 1-octanol, quinoline, and chloroform (78 <i>D</i> values) and polar primary alcohols in nonpolar benzene and <i>n</i>-octane (24 <i>D</i> values) gives an average\nabsolute percentage difference of ∼3% between the 102 experimental\nand calculated <i>D</i> values. Consideration of the solvent’s\ntemperature-dependent changes in the degree of aggregation due to\nhydrogen bonding was necessary for the <i>n</i>-alkanes\nin 1-octanol. Good agreement was not found for primary alcohols in\n1-octanol due to solute–solvent hydrogen bonding. A correlation\nthat depends on the solutes’ molar volumes instead of their\nchain lengths gives worse agreement than the bead model for the <i>n</i>-alkanes in polar solvents and primary alcohols and <i>n</i>-alkanes in nonpolar solvents.