Excess molar volumes of methanol or ethanol plus n-polyethers at 298.15 K

Excess molar volumes V-m(E) at 298.15 K and atmospheric pressure for methan ol and ethanol + 2,5-dioxahexane, + 3,6-dioxaoctane, + 2,5,8-trioxanonane, + 3,6,9-trioxaundecane, + 5,8,11-trioxapentadecane, + 2,5,8,11-tetraoxadode cane, and + 2,5,8,11,14-pentaoxapentadecane have been obtained from densiti es measured with an Anton-Paar DMA 602 vibrating-tube densimeter. All the e xcess volumes are negative over the whole mole fraction range. The V-m(E) c urves are shifted to the region rich in the alkanol, increasing their asymm etry with the number of oxygen groups in the polyethers. Results seem to re mark the predominant contribution of free volume effects on interactional e ffects, particularly when the ethers are of the type CH3-(O-CH2CH2)(m)-CH3. In the case of polyethers with longer n-alkyl chain ends, self-association of methanol and ethanol is more relevant. A short comparative study with r esults for mixtures with higher 1-alkanols and polyethers is also presented .