Molar heat capacity of aqueous solutions of 1,3-diaminopropane and 1,4-diaminobutane and their piperazine blends

• Molar heat capacity of aqueous solutions of 1,3-diaminopropane, 1,4-diaminobutane, and their piperazine blends were measured.
• The temperature studied was 303.2–53.2 K.
• The measured data were reported as functions of temperature and composition.
• The measured data were satisfactorily represented by the applied correlations.

The molar heat capacity, Cp, of aqueous 1,3-diaminopropane (DAP), 1,4-diaminobutane (DAB) and their corresponding blends with piperazine (PZ) were measured at temperatures from 303.2 K to 353.2 K by differential scanning calorimetry. The correlation of Cp of the aqueous binary mixtures with temperature and concentration was successfully described by a Redlich–Kister type equation using excess molar heat capacity data. A modified Sohnel and Novotny equation was used to represent the temperature and concentration dependence of Cp of the ternary mixtures. The average absolute deviations between the experimental and the predicted Cp data were 0.2% and 0.1% for the binary and ternary mixtures, respectively. The results suggest that the experimental data presented in this work were represented well by the proposed correlations.