物理化学学报 >> 2004, Vol. 20 >> Issue (06): 626-630.doi: 10.3866/PKU.WHXB20040615

研究论文 上一篇    下一篇

水-乙醇二元体系共沸混合物的热力学研究

南照东;谭志诚;孙立贤   

  1. 曲阜师范大学化学系,曲阜 273165;中国科学院大连化学物理研究所热化学实验室,大连 116023
  • 收稿日期:2003-11-28 修回日期:2004-03-02 发布日期:2004-06-15
  • 通讯作者: 南照东 E-mail:zdnan65@163.com

Thermodynamic Investigation of the Azeotrope of Water and Ethanol

Nan Zhao-Dong;Tan Zhi-Cheng;Sun Li-Xian   

  1. Department of Chemistry, Qufu Normal University, Qufu 273165;Thermochemistry Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023
  • Received:2003-11-28 Revised:2004-03-02 Published:2004-06-15
  • Contact: Nan Zhao-Dong E-mail:zdnan65@163.com

摘要: 用全自动低温绝热量热计测定了水、乙醇以及水和乙醇组成的共沸混合物在不同温区的摩尔热容Cp,m. 建立了共沸混合物Cp,m与温度T的函数关系.结果表明,水和乙醇组成的共沸混合物在98.496 K发生玻璃态转化,在158.939 K 和270.95 K发生固-液相变.获得了其相应的相变焓和相变熵.计算了以298.15 K为基准的该共沸混合物的热力学函数和超额热力学函数.

关键词: 绝热量热法, 热容, 共沸混合物, 水, 乙醇

Abstract: The molar heat capacities of the azeotrope in the binary system of water and ethanol were measured by an adiabatic calorimeter in the temperature range from 78 K to 320 K. The functions of the heat capacity with respect to the thermodynamic temperature were established. The glass transition occurred at 98.496 K. The phase transitions took place in the temperature ranges from 123.08 K to 156.96 K and 269.03 K to 273.20 K corresponding to the solid-solid phase transition of ethanol, solid-liquid phase transition of ethanol, and solid-liquid phase transition of water, respectively. The thermodynamic functions and the excess thermodynamic functions of the azeotrope relative to 298.15 K were derived based on the relationships of the thermodynamic functions and the function of the measured heat capacity with respect to the temperature.

Key words: Adiabatic calorimetry, Heat capacity, Azeotrope, Water, Ethanol