DISQUAC calculation of thermodynamic properties of ether + 1-alkanol systems. Comparison with UNIFAC calculation

The experimental data available in literature on vapour-liquid equilibrium (VLE), excess molar Gibbs energies (GE), excess molar enthalpies (HE), activity coefficients at infinite dilution (γix) and excess molar heat capacities (CpE) of binary mixtures of monoethers, or polyethers + 1-alkanols are examined on the basis of the DISQUAC group contribution model. The components in the mixture are characterized by three types of groups of surfaces: aliphatic (CH3 or CH2 groups); hydroxyl (OH group) and oxygen (O group). Interaction parameters for aliphatic/oxygen and aliphatic/hydroxyl contacts have been estimated previously from n-alkane + ether mixtures and n-alkane + 1-alkanol mixtures respectively. In this work, we have determined the interaction parameters between the oxygen and hydroxyl groups in ether + 1-alkanol systems. Monoethers, and diethers + 1-alkanols systems are represented using different interaction parameters due to the proximity effect of oxygen atoms (i.e. OCCO) in diethers. The interaction parameters for monoether + 1-alkanol systems behave as follows: the dispersive coefficients Ceh,1DIS increase with the size of the monoethers, Ceh,2DIS increases with the size of the 1-alkanols and Ceh,3DIS remains constant; the quasi-chemical coefficients Ceh,1QUAC are constant and the Ceh,2QUAC and Ceh,3QUAC decrease regularly with the alkyl chain length in monoethers and 1-alkanols. The interaction parameters for diethers + 1-alkanols are different but, vary in a similar way; they can be used for describing other polyether + 1-alkanol systems. The DISQUAC calculations are compared to those obtained with the modified UNIFAC model (Dortmund). These comparisons show that DISQUAC has more flexibility for correlation and prevision.