Low-Temperature Heat Capacities and Thermodynamic Properties of 2-Aminopyridine

摘要

Low-temperature heat capacities of 2-aminopyridine have been measured by a precision automatic adiabatic calorimeter over the temperature range from 78 to 370 K. A solid-liquid phase transition was observed from 315 to 335 K. The peak temperature, molar enthalpy and entropy of the solid-liquid phase transition were determined to be: (330.09 + 0.01) K, (18.33 ± 0.05) kJ mol~(-1) and (55.53 ± 0.14) J K~(-1) mol~(-1), respectively. In addition, the mole fraction purity, the melting temperature of the given sample and that of pure sample were calculated to be (99.54 ± 0.06) %, (330.20 ± 0.01) K and (330.43 ± 0.01) K by means of fractional melting method. The results showed that the melting temperature of the sample from adiabatic calorimetry agreed basically with that from theoretical analysis of the purity.