EXCESS MOLAR VOLUMES OF 1-PROPANOL PLUS N-POLYETHERS AT 298.15 K

Excess molar volumes V-m(E) at 298.15 K and atmospheric pressure for 1 -propanol + 2,5-dioxahexane, 3,6-dioxaoctane, 2,5,8-trioxanonane, 3,6, 9-trioxaundecane or 5,8,11-trioxapentadecane have been calculated from densities measured with an Anton-Paar DMA 602 vibrating-tube densimet er. All the excess molar volumes are negative over the whole mole-frac tion range, nearly symmetrical for mixtures with diethers and slightly skewed towards the region of high mole fraction of 1-propanol for mix tures with triethers. The value of V-m(E) decreases as the n-alkyl cha in end length of the diethers or the triethers increases. When the n-a lkyl chain end of the polyethers is the methyl group (-CH3), V-m(E) is very small in absolute value and similar for the diethers and triethe rs, whereas when the end group is larger than the methyl group, the va lue of V-m(E) is more negative for the diethers than for the triethers . These results, together with previously published excess molar entha lpies, suggest the formation of hydrogen bonds between the functional group -OH of the 1-alkanol and the -O-atoms of the polyethers. (C) 199 7 Elsevier Science B.V.