Thermodynamics of alkanoate + alkane binary mixtures. Concentration dependence of excess heat capacities and volumes

Excess molar volumes, VE, and excess molar heat capacities at constant pressure, [Formula: see text], have been obtained for some n-alkanoate + n-alkane mixtures at 298.15 K from density and volumetric heat capacity measurements using liquid-flow techniques. The alkanoates selected were n-propyl methanoate, methyl ethanoate, ethyl ethanoate, methyl propanoate, methyl butanoate, methyl pentanoate, and methyl octanoate. VE are positive for all systems and rather symmetric. The composition dependence of [Formula: see text] is typically of the ω-shaped type with two minima, more or less pronounced, which are separated by a positive part in the case of the more polar esters, i.e. n-propyl methanoate and methyl ethanoate. These results are discussed in terms of possible changes in conformation of both the ester and the n-alkane.