Low-temperature heat capacities of 2-chloro-N,N-dimethylnicotinamide were precisely measured with a high-precision automated adiabatic calorimeter over the temperature range from 82 K to 380 K. The compound was observ...Low-temperature heat capacities of 2-chloro-N,N-dimethylnicotinamide were precisely measured with a high-precision automated adiabatic calorimeter over the temperature range from 82 K to 380 K. The compound was observed to melt at （342.15±0.04） K. The molar enthalpy AfusionHm, and entropy of fusion, △fusionSm, as well as the chemical purity of the compound were determined to be （21387±7） J·mol^-1, （62.51±0.01） J·mol^-1·K^-1, （0.9946±0.0005） mass fraction, respectively. The extrapolated melting temperature for the pure compound obtained from fractional melting experiments was （342.25±0.024） K. The thermodynamic function data relative to the reference temperature 298.15 K were calculated based on the heat capacity measurements in the temperature range from 82 to 325 K. The thermal behavior of the compound was also investigated by different scanning calorimetry.展开更多
基金Project supported by the National Natural Science Foundation of China （No. 20373072） and the Natural Science Foundation of Shaanxi Province （No. 2001H11）.
文摘Low-temperature heat capacities of 2-chloro-N,N-dimethylnicotinamide were precisely measured with a high-precision automated adiabatic calorimeter over the temperature range from 82 K to 380 K. The compound was observed to melt at （342.15±0.04） K. The molar enthalpy AfusionHm, and entropy of fusion, △fusionSm, as well as the chemical purity of the compound were determined to be （21387±7） J·mol^-1, （62.51±0.01） J·mol^-1·K^-1, （0.9946±0.0005） mass fraction, respectively. The extrapolated melting temperature for the pure compound obtained from fractional melting experiments was （342.25±0.024） K. The thermodynamic function data relative to the reference temperature 298.15 K were calculated based on the heat capacity measurements in the temperature range from 82 to 325 K. The thermal behavior of the compound was also investigated by different scanning calorimetry.
