Binary mutual diffusion coefficient of aqueous solutions of propylene glycol and dipropylene glycol

Binary mutual diffusion coefficient data for aqueous solutions of propylene and dipropylene glycols were measured using the Taylor dispersion technique for each aqueous binary system at different concentrations (x1 = 0.2–0.80) and temperatures (303.2–323.2 K). The measured data were fit to different empirical and semi-theoretical models and compared with the values predicted from such models. The measured mutual diffusion coefficient data are well represented by either rough hard-sphere or UNIDIF model. On the side, the infinite dilution diffusion coefficient has been found greater at lower glycol molecular weight, an observation that corroborates with the property's dependence on free volume.