Volumetric and Solid + Liquid Equilibrium Data for Linear 1-Alkanol + Decylamine Mixtures. Analysis in Terms of ERAS, DISQUAC, and Modified UNIFAC

Abstract

Solid + liquid phase diagrams have been determined for 1-octanol, 1-nonanol, 1-decanol, or 1-undecanol + decylamine mixtures. Solid addition compounds form with the empirical formulas: C 8 H 17 OH.C 10 H 23 N, C 9 H 19 OH.C 10 H 23 N, C 10 H 21 OH.C 10 H 23 N, and C 11 H 23 OH.C 10 H 23 N. All are congruently melting compounds. Compound formation is attributed to a strong A-B interaction. The excess molar volumes, V E m , have been determined for these mixtures at 298.15 K and atmospheric pressure. The systems exhibit very large negative excess molar volumes, V E m , and excess molar enthalpies, H E m . The V E m curves are nearly symmetrical. Strong cross-association between hydroxyl and amine groups (OH...NH 2 ) is a dominant effect, and it causes high negative values of V E m and H E m and 1:1 congruently melting solid compounds at lower temperatures. Our experimental data on V E m and the literature data on H E m were treated in terms of the ERAS model, DISQUAC, and modified UNIFAC. The ERAS model consistently describes V E m and H E m of the studied mixtures.