Molar heat capacities of diethylenetriamine and 3-(methylamino)propylamine, their aqueous binaries, and aqueous ternaries with piperazine

• Heat capacities of diethylenetriamine and 3-(methylamino)propylamine, their aqueous binaries, and aqueous ternaries containing piperazine were measured.
• The temperature studied was 303.15–353.15 K.
• The measured data were reported as functions of temperature and composition.
• The measured data were represented satisfactorily by the applied correlations.

The molar heat capacities, CP, of two new potential polyamine CO2 absorbents: diethylenetriamine (DETA) and 3-(methylamino)propylamine (MAPA), their aqueous binaries, and aqueous ternaries containing piperazine (PZ) were measured at temperatures from 303.15 K to 353.15 K. Measurements were performed at atmospheric pressure by heat flow differential scanning calorimetry. A linear relation suitably represented the temperature dependence of the CP of pure amines. The excess molar heat capacities, CPE, of the binary solutions were investigated, and the data were represented as function of temperature and composition using a Redlich–Kister-type equation. The CP of the ternary mixtures was correlated with temperature and amine concentration using the Sohnel and Novotny equation. Results showed that the calculated data agree very well with the experimental CP values at average absolute deviation values of 0.13%, 0.20, and 0.06 for the pure, binary, and ternary systems, respectively.