Abstract
The heat capacity of HBA has been measured between 16 and 385 K with an adiabatic calorimeter. A crystal-crystal phase transition was observed at about 73 K. The enthalpy and entropy of this transition were 0.192 kJ mor−1and 2.70J K−1 mol−1, respectively. The crystal melted into the isotropic liquid at 321.63 K. The enthalpy and entropy of melting were 30.91 kJ mol−1and 96.1 J K−1 mol−1. The melting entropy of HBA agreed well with those of the homologous compounds in which the p-position of the aniline ring is substituted by CN, Cl, F and CH3, respectively.