The Partial Molar Volumes of Normal Alkanols in Aqueous Sodium Dodecyl Sulfate Solutions

The partial molar volumes of normal alkanols (CmH2m+1OH, m=1–10) in aqueous sodium dodecyl sulfate solutions were measured by a dilatometric method at 25 °C. For the alkanols (m=4–8), different constant partial molar volumes appeared below and above the CMC value, whereas no such difference was observed for lower alkanols (m=1–3), and for higher alkanols (m=8–10) the partial molar volumes above the CMC value are nearly identical with their own molar volumes. The partition coefficient of the alkanols between the bulk and micellar phases is estimated on the basis of the volumetric results.