J.A. Peña

Thermodynamic study on binary mixtures of propyl ethanoate and an alkan-1-ol (C2–C4). Isobaric vapor–liquid equilibria and excess properties

Abstract This paper presents an analysis on binary mixtures of propyl ethanoate and an alkan-1-ol (ethanol to butanol) using the results obtained for different thermodynamic quantities such as the isobaric vapor–liquid equilibrium (VLE) data at pressures of 101.3 kPa and 160.0 kPa, excess enthalpies and excess volumes. Vapor pressures for the same normal alkanols used, determined using the same equilibrium still, are also presented. The three mixtures present expansive and endothermic effects during the mixing process. All investigated mixtures show positive deviations from ideality. For two mixtures, azeotropes are found: for propyl ethanoate+ethanol, x az =0.078, T az =351.02 K at p =101.3 kPa, while x az =0.041, T az =363.14 K at p =160.0 kPa; for propyl ethanoate+propan-1-ol, x az =0.387, T az =367.63 K at p =101.3 kPa, while x az =0.313, T az =381.02 K at p =160.0 kPa. Correlations of the activity coefficients, reduced excess Gibbs energy, and mixing enthalpy using a new equation containing temperature-dependent coefficients were good for all three binary mixtures. The ASOG and Nitta et al. models yielded the best prediction of equilibrium properties for the mixtures containing ethanol while one of the modified versions of UNIFAC model gave the best predictions of equilibrium properties for the remaining binary systems. Using the same set of parameters the UNIFAC and Nitta et al. models also yielded acceptable estimates of the excess enthalpies for the same mixtures.

Excess molar enthalpies of methyl alkanoates + n-nonane at 298.15 k

Abstract Microcalorimetric measurements of excess enthalpies were carried out over the whole concentration range for mixtures of nine methyl alkanoates (from acetate to decanoate) with n -nonane at 298.15 K. From these data, information could be obtained about the interactions between both chemical species. All show positive excess molar enthalpies which decrease with increasing length of the aliphatic chain of the methyl alkanoate.

Isobaric expansivities of the binary mixtures C3H7(OH) + CnH2n + 2 (n = 11, 12) between 288.15 and 318.15 K

Abstract Densities and refractive indices of the binary mixtures of propan-1-ol with n-undecane and with n-dodecane at 288.15, 298.15, 308.15 and 318.15 K have been determined as a function of the concentration of the n-alkanol. The results were employed in order to determine the mean thermal expansion coefficients, both of the pure compounds and of their mixtures by using, on the one hand, the basic expression α= −(∂ ln ϱ/∂t)p and, on the other, certain empirical expressions arising from the definitions of specific refraction given by Gladstone and Dale, Lorentz and Lorenz and Eykman. The results obtained for αE are also discussed.

Experimental and predicted mixing enthalpies for several methyl n-alkanoates with n-pentane at 298.15 K: Application of the UNIFAC model

Abstract Mixing enthalpy values for nine binary systems consisting of methyl esters (from ethanoate to n -decanoate) and n -pentane measured at 298.15 K and normal atmospheric pressure using a Calvet microcalorimeter are reported. The experimental results showed that the h E values are positive over the entire range of concentrations and that they decrease in a regular manner as the ester chain-length increases. The experimental values were compared with predictions obtained by applying the UNIFAC model using various options. Mean estimation errors for the nine systems ranged between 7.1% and 25.6%, depending on the individual model case applied.

Enthalpies of mixing at 298.15 K of a methyl alkanoate (from acetate to pentanoate) with n-alkanes (n-tridecane and n-pentadecane)

Excess molar enthalpies hE have been measured for the binary liquid mixtures of four methyl alkanoates (acetate, propanoate, butanoate and pentanoate) with two n-alkanes (n-tridecane and n-pentadecane) at 298.15 K, using an isothermal microcalorimeter. All the mixtures studied were endothermic, the hE values for a given n-alkane decreasing with lengthening of the aliphatic chain of the methyl ester. By contrast, the values of hE increased quasi-regularly as the number of carbon atoms in the n-alkane increased.