Vapour-liquid equilibria, enthalpy of vaporisation, and excess Gibbs energies of binary mixtures of {3,3-diamino-N-methyldipropylamine (DNM) (or N,N,N′,N′′,N′′-pentamethyldiethylenetriamine (PMDETA)) + water}

•Experimental vapor pressures of pure DNM, PMDETA and their aqueous solutions are reported.•The investigated temperatures are 273 K through 363 K.•The DNM binary system exhibits negative deviations in GE values.•The PMDETA system exhibit sinusoidal and positive deviations in GE values.•The 3rd order Redlich–Kister, and NRTL or UNIQUAC models have been used to correlate the (P-x-y) data.