物理化学学报 >> 2002, Vol. 18 >> Issue (06): 481-485.doi: 10.3866/PKU.WHXB20020601

通讯    下一篇

稀土钬及铒钇丙氨酸配合物的量热与热分析研究

刘北平;谭志诚;南照东;刘平;孙立贤;徐芬   

  1. 中国科学院大连化学物理研究所热化学实验室,大连 116023;湖南常德师范学院化学化工系,常德 415000
  • 收稿日期:2002-01-28 修回日期:2002-03-26 发布日期:2002-06-15
  • 通讯作者: 谭志诚 E-mail:tzc@dicp.ac.cn

Calorimetric Study and Thermal Analysis of [Ho2(Ala)4(H2O)8]Cl6 and >;[ErY(Ala)4(H2O)8](ClO4)6

Liu Bei-Ping;Tan Zhi-Cheng;Nan Zhao-Dong;Liu Ping;Sun Li-Xian;Xu Fen   

  1. Thermochemistry Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023;Department of Chemistry, Changde Normal College, Changde 415000
  • Received:2002-01-28 Revised:2002-03-26 Published:2002-06-15
  • Contact: Tan Zhi-Cheng E-mail:tzc@dicp.ac.cn

摘要: 合成了两种固态稀土丙氨酸配合物[Ho2(Ala)4(H2O)8]Cl6和[ErY(Ala)4(H2O)8](ClO4)6 (Ala为丙氨酸),用量热和热分析方法研究了这两种配合物的热力学性质.用全自动高精密绝热量热计测定了在78~377 K温区内的低温热容.对于[Ho2(Ala)4(H2O)8]Cl6,在214~255 K温区内发现一固-固相变,其相变温度为235.09 K.对于[ErY(Ala)4(H2O)8](ClO4)6,在99~121 K温区内也发现一固-固相变,其相变温度为115.78 K. [Ho2(Ala)4(H2O)8]Cl6固-固相变焓为3.02 kJ• mol-1,相变熵为12.83 J•K-1•mol-1; [ErY(Ala)4(H2O)8](ClO4)6 固-固相变焓为1.96 kJ•mol-1,相变熵为16.90 J•K-1•mol-1.同时,用TG技术在40~800 ℃温区研究了两配合物的热稳定性.由TG/DTG曲线分析可知, [Ho2(Ala)4(H2O)8]Cl6从80 ℃到479 ℃热分解分两步完成, [ErY(Ala)4(H2O)8](ClO4)6从120 ℃到430 ℃热分解分三步完成.

关键词: [Ho2(Ala)4(H2O)8]Cl6, [ErY(Ala)4(H2O)8](ClO4)6, 绝热量热, 热容, 热分解

Abstract: Two solid complexes of rare-earth compounds with alanine, [Ho2(Ala)4(H2O)8]Cl6 and [ErY(Ala)4(H2O)8](ClO4)6 (Ala=alanine) were synthesized,and a calorimetric study and thermal analysis for the two complexes were performed through adiabatic calorimetry and thermogravimetry. The low-temperature heat capacities of [Ho2(Ala)4(H2O)8]Cl6 and [ErY(Ala)4(H2O)8](ClO4)6 were measured with an automated adiabatic precision calorimeter over the temperature range from 78 to 377 K. Solid-solid phase transitions were found between 214 K and 255 K with a peak temperature of 235.09 K for [Ho2(Ala)4(H2O)8]Cl6,between 99 K and 121 K with a peak temperature of 115.78 K for [ErY(Ala)4(H2O)8](ClO4)6.The enthalpies and entropies of the phase transitions were determined to be 3.02 kJ•mol-1,12.83 J•K-1•mol-1 for [Ho2(Ala)4(H2O)8]Cl6; 1.96 kJ•mol-1,16.90 J•K-1•mol-1 for [ErY(Ala)4(H2O)8](ClO4)6, respectively. Thermal decomposition of the two complexes were investigated in the temperature range of 40~800 ℃ by using the thermogravimetric and differential thermogravimetric (TG/DTG ) analysis techniques. The TG/DTG curves showed that the decomposition started from 80 ℃ and ended at 479 ℃,completed in two steps for [Ho2(Ala)4(H2O)8]Cl6,and started from 120 ℃ and ended at 430 ℃,completed in three steps for [ErY(Ala)4(H2O)8](ClO4)6,respectively.The possible mechanisms of the thermal decompositions were elucidated.

Key words: [Ho2(Ala)4(H2O)8]Cl6, [ErY(Ala)4(H2O)8](ClO4)6, Adiabatic calorimetry, Heat capacity, Thermal decomposition