## Abstract

This work analyzes the utility of a new model to correlate thermodynamic properties of solutions, the foundations of which have been published in a previous study. The model is applied to a set of experimental data for several properties of binary systems of methanol with four butyl alkanoates (vapor-liquid equilibria at p = 141.32 kPa and excess enthalpies and volumes at 298.15 and 318.15 K). Vapor-liquid equilibrium data (VLE) indicate that the four binary systems deviate positively from Raoult's law and do not present azeotrope. Excess enthalpies (h^{E}) are positive for the entire range of compositions and decrease regularly with increasing length of the ester chain, with (a,h^{E}/A,T)_{p,x} > 0. The excess volumes (v^{E}) decrease regularly with the length of the acid chain; they are positive for the binary systems of methanol with butyl (methanoate, ethanoate, and propanoate) and become negative for the system with butyl butanoate, with (a,v^{E}/A,T)_{p,x} > 0. The new model can be used to obtain a satisfactory correlation for Gibbs function g^{E} = g^{E}(p, T, x_{i}), and for its derivatives. Correlation procedures for the data are described for the stages (x, h^{E}) a' [x, g^{E}(T)] for the isobaric data reported here and (x, v^{E}) a' [x, g^{E}(p)] for isothermal data reported in the literature. The new method allows a better correlation than the one obtained with the classical models of Wilson, NRTL, and UNIQUAC. We also present a unique correlation of all the properties of the methanol + butyl ethanoate system in the form of an analytical expression I(p, T, x, y) = 0 and conclude that, on the whole, its implementation can be considered an advance in the data treatment of the properties of liquid solutions.

Original language | English |
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Pages (from-to) | 9548-9558 |

Number of pages | 11 |

Journal | Industrial and Engineering Chemistry Research |

Volume | 49 |

Issue number | 19 |

DOIs | |

State | Published - 6 Oct 2010 |

## ASJC Scopus subject areas

- General Chemistry
- General Chemical Engineering
- Industrial and Manufacturing Engineering