Estimation of DISQUAC interchange energy parameters for n-alkylamine + n-alkane mixtures

Abstract

Abstract Velasco I., Fernandez J., Otin S. and Kehiaian H.V., 1991. Estimation of DISQUAC interchange energy parameters for n-alkylamine + n-alkane mixtures. Fluid Phase Equilibria, 69:15-32. The experimental literature data on vapor-liquid equilibria, molar excess Gibbs energies, molar excess enthalpies and activity coefficients at infinite dilution of n-alkylamine + n-alkane mixtures are interpreted in terms of the DISQUAC group contribution model. The systems are characterized by two types of groups or contact surfaces: alkane (CH3, CH2) and amine (NH2). Interchange coefficients of the n-alkylamine + n-alkane mixtures, calculated from experimental G e and H e values, show a variation in the case of short-chain n-alkylamines with the number of C atoms u, obtaining a constant value for n-alkylamines with u ⩾ 4. The model reproduces most of the experimental data quite well and predicts the partial miscibility for methylamine + n-alkanes at low temperatures. The experimental liquid-liquid equilibrium curves of ammonia + n-alkanes may be also calculated using the interchange coefficients of the amines extrapolated to u = 0.