Thermodynamic properties of (a propyl ester plus an n-alkane).: XII.: Excess molar enthalpies and excess molar volumes for {xCH3(CH2)u-1COO(CH2)2CH3+(1-x)CH3(CH2)2v+1CH3} with u = (1 to 3), and v = (1 to 7)

Excess molar enthalpies H-m(E) and excess molar volumes V-m(E) were determined at the temperature 298.15 K for 21 binary mixtures of three propyl esters (ethanoate, propanoate, and butanoate) and seven odd n-alkanes (pentane to heptadecane). All the mixtures exhibited endothermic enthalpies which decreased quasi-exponentially with the ester chain length in the same proportion as their dipole effects. The variations of the excess molar volumes for these mixtures followed a similar decreasing trend, with contractions observed in the systems consisting of high molar mass esters and lowest n-alkanes. These effects have been interpreted on the basis of molecular interactions. The UNIFAC, DISQUAC, and Nitta-Chao models were used to estimate the thermodynamic properties considered, and yielded acceptable results. (C) 1999 Academic Press.