DISQUAC CALCULATION OF THERMODYNAMIC PROPERTIES OF ETHER PLUS 1-ALKANOL SYSTEMS - COMPARISON WITH UNIFAC CALCULATION

The experimental data available in literature on vapour-liqued equilib rium (VLE), excess molar Gibbs energies (G(E)), excess molar enthalpie s (H-E), activity coefficients at infinite dilution (gamma(i)(infinity )) and excess molar heat capacities (Cp(E)) of binary mixtures of mono ethers or polyethers + 1-alkanols are examined on the basis of the DIS QUAC group contribution model. The components in the mixture are chara cterized by three types of groups of surfaces: aliphatic (CH3 or CH2 g roups); hydroxyl (OH group) and oxygen (O group). Interaction paramete rs for aliphatic/oxygen and aliphatic/hydroxyl contacts have been esti mated previously from n-alkane + ether parameters between the oxygen a nd hydroxyl groups in ether + 1-alkanol systems behave as follows: the dispersive coefficients C-eh,1(DIS) remains constant;the quasi-chemic al coefficients C-eh,1(DIS), increase with the size of the monoethers, C-eh,2(DIS) decrease regularly with the alkyl chain length in monoeth ers and 1-alkanols. The interaction parameters for diethers + 1-alkano ls are different but, vary in a similar way; they can be used for desc ribing other polyether +1-alkanol systems. The DISQUAC calculations ar e compared to those obtained with the modified UNIFAC model (Dortmund) . These comparisons show that DISQUAC has more flexibility for correla tion and prevision.