物理化学学报 >> 2013, Vol. 29 >> Issue (10): 2123-2128.doi: 10.3866/PKU.WHXB201306051

热分析动力学和热动力学 上一篇    下一篇

Ho(NO3)3(C2H5O2N)4·H2O的低温热容和热力学函数

高肖汉1, 徐培1, 段文超1, 吕雪川1, 谭志诚2, 鲁强1   

  1. 1 辽宁石油化工大学化学化工与环境学部化学与材料科学学院, 辽宁 抚顺 113001;
    2 中国科学院大连化学物理研究所热化学实验室, 辽宁 大连 116023
  • 收稿日期:2013-03-15 修回日期:2013-06-05 发布日期:2013-09-26
  • 通讯作者: 吕雪川, 谭志诚 E-mail:xuechuanster@gmail.com;tzc@dicp.ac.cn
  • 基金资助:

    国家自然科学基金(21103078, 21003069)资助项目

Low-Temperature Heat Capacity and Thermodynamic Functions of Ho(NO3)3(C2H5O2N)4·H2O

GAO Xiao-Han1, XU Pei1, DUAN Wen-Chao1, LÜ Xue-Chuan1, TAN Zhi-Cheng2, LU Qiang1   

  1. 1 School of Chemistry and Material Science, College of Chemistry and Chemical Engineering and Environmental Engineering, Liaoning Shihua University, Fushun 113001, Liaoning Province, P. R. China;
    2 Thermochemistry Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, Liaoning Province, P. R. China
  • Received:2013-03-15 Revised:2013-06-05 Published:2013-09-26
  • Contact: DUAN Wen-Chao, LÜ Xue-Chuan E-mail:xuechuanster@gmail.com;tzc@dicp.ac.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21103078, 21003069).

摘要:

合成了稀土(钬, Ho)-氨基酸(甘氨酸, C2H5O2N)二元配合物Ho(NO3)3(C2H5O2N)4·H2O, 并且通过化学分析、元素分析和红外(IR)光谱对配合物进行了表征. 用高精度全自动绝热量热仪, 测定了该配合物在80-390 K温度区间的定压摩尔热容(Cp,m). 利用实验测定的热容数据, 采用最小二乘法, 将热容曲线上热容峰以外的两段平滑区的摩尔热容对折合温度进行拟合, 建立了热容随折合温度变化的多项式方程. 根据热容与焓、熵的热力学关系,计算出了配合物在80-390 K温度区间内,每隔5 K,相对于298.15 K的摩尔热力学函数(HT,m-H298.15,m)和(ST,m-S298.15,m). 通过热容曲线分析, 计算出了350 K附近转变过程的焓变(ΔtrsHm)和熵变(ΔtrsSm). 用差示扫描量热法(DSC)测定了配合物的热稳定性.

关键词: 稀土配合物, Ho(NO3)3(C2H5O2N)4·H2O, 绝热量热法, 热容, 热力学函数, 热分析

Abstract:

A complex of a rare-earth metal (Ho) nitrate with glycine (C2H5O2N), Ho(NO3)3(C2H5O2N)4·H2O, was synthesized, and characterized by chemical analysis, elemental analysis, and infrared (IR) spectroscopy. The thermodynamic properties of the complex were also studied. The low-temperature molar heat capacities at constant pressure (Cp,m) of the complex were measured using a high-precision automatic adiabatic calorimeter over the temperature range from80 to 390 K. The experimental molar heat capacities at constant pressure were used to deduce the polynomial equations for the heat capacity as a function of reduced temperature by applying the least-squares method to the two smooth stages of the curve. Based on the thermodynamic relationships among heat capacity, entropy, and enthalpy, the thermodynamic functions (HT,m-H298.15,m) and (ST,m-S298.15,m) were derived from the heat capacity data, with temperature intervals of 5 K. The molar enthalpy and entropy changes of the transition process at about 350 K (ΔtrsHm and ΔtrsSm) were calculated from the heat capacity curve. The thermal stability of the complex was determined using differential scanning calorimetry (DSC).

Key words: Rare earth complex, Ho(NO3)3(C2H5O2N)4·H2O, Adiabatic calorimetry, Heat capacity, Thermodynamic function, Thermal analysis

MSC2000: 

  • O642.3