Diffusion of nonassociated and hydrogen-bonded aromatic compounds in ethanol: A bifunctional model for limiting mutual diffusivities

•Diffusivities of aromatic compounds were measured by Taylor’s dispersion method.•The data of nonpolar solutes are well described by a molecular-hydrodynamic relation.•Quantification and correlation of H-bonding effects on diffusivity are demonstrated.•A new model for tracer diffusivities of aromatic solutes in ethanol is proposed.•The proposed model is applicable to a total of 143 experimental diffusivities in this study. Tracer diffusivities of disc-shaped aromatic compounds in ethanol were measured at various temperatures. The data of the polar solutes capable of hydrogen bonding were compared with those of the nonpolar and nonassociated ones to quantify the hydrogen-bonding effects on diffusivity. The effects were successfully described using the overall hydrogen-bonded acidity and basicity values of the polar molecules. The diffusivities of the nonpolar solutes at different temperatures were also found to correlate well with a new fractional molecular-hydrodynamic (FMH) relation. A novel model that combined the FMH relation for nonpolar solutes with the effects of hydrogen-bonding on diffusivity for polar molecules was proposed for the tracer diffusivities of pseudoplanar aromatic compounds in ethanol. A general equation developed from this model was demonstrated to be capable of calculating a total of 143 diffusivities of both the polar and nonpolar aromatic solutes in ethanol at different temperatures to a standard deviation of 2.56%.