Phase equilibrium properties of binary mixtures containing 1,3-pentanediamine (or 1,5-diamino-2-methylpentane) and water at several temperatures

•Experimental vapor pressures of pure 1,3-pentanediamine, 1,5-diamino-2-methylpentane and their aqueous solutions are reported.•The investigated temperatures are (273 to 363) K.•The two binary systems exhibit negative deviations in GE values.•The NRTL, UNIQUAC and Modified UNIFAC (Do) models have been used.

The vapor pressures of (1,3-pentanediamine + water), or (1,5-diamino-2-methylpentane + water) binary mixtures, and of pure 1,3-pentanediamine or 1,5-diamino-2-methylpentane components were measured by means of a static device at temperatures between (273 and 363) K. The data were correlated with the Antoine equation. From these data excess Gibbs functions (GE) were calculated for several constant temperatures and fitted to a three order Redlich–Kister equation using the Barker’s method. The (1,3-pentanediamine + water) or (1,5-diamino-2-methylpentane + water) binary systems exhibit negative deviations in GE for all investigated temperatures over the whole composition. Additionally, the NRTL UNIQUAC and Modified UNIFAC (Do) models have been used for the correlation or prediction of the total pressure.