Thermodynamic properties of (a butyl ester plus an n-alkane). XIII. H-m(E) and V-m(E) for {xCH(3)(CH2)(u-1)CO2(CH2)(3)CH3+(1-x) CH3(CH2)(2v+1)CH3}, where u=1 to 3 and v=1 to 7

Abstract

In the framework of a series of studies carried out by our research team, the excess molar enthalpies HmE and excess molar volumes VmE for 21 binary mixtures composed of one of three butyl esters (ethanoate, propanoate, and butanoate) and one of seven odd n-alkanes (pentaneto heptadecane) were determined experimentally at T = 298.15 K. Experimentation showed the mixing processes for these systems to be endothermic, with the HmE values varying quasi-linearly with n-alkane chain length; there is also a regular variation in the VmE values, though the mixtures of the three butyl esters with pentane presented contraction effects with values of VmE that were more negative than expected. The most probable molecular interactions taking place in (ester + n-alkane) systems are discussed. Comparison of the experimental results with certain theoretical groupcontribution modes showed that differences in the estimates increased with increasing molar mass of the mixture components, indicating a need to improve modeling by adapting the modes so that they more closely reflect the special circumstances that affect the behaviour of the mixtures in question. © 2000 Academic Press.