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化学学报
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化学学报 ›› 2006, Vol. 64 ›› Issue (1): 70-78. 上一篇    下一篇

研究论文

稀土配合物[Pr(C3H7NO2)2(C3H4N2)(H2O)](ClO4)3的标准生成焓及热分解动力学研究

但悠梦*,1,2， 胡卫兵1，余华光2，董家新2，刘义2，屈松生2   

  1. (1湖北民族学院化学与环境工程学院 恩施 445000)
    (2武汉大学化学与分子科学学院 武汉 430072)
  • 投稿日期:2004-10-26 修回日期:2005-09-17 发布日期:2006-01-14
  • 通讯作者: 但悠梦

Standard Molar Enthalpy of Formation and Thermal Decomposition Kinetic Study of Rare Earth Complex [Pr(C3H7NO2)2(C3H4N2)(H2O)](ClO4)3

DAN You-Meng*,1,2, HU Wei-Bing1, YU Hua-Guang2, DONG Jia-Xin2, LIU Yi2, QU Song-Sheng2   

  1. (1 School of Chemistry and Environmental Engineering, Hubei Institute for Nationalities, Enshi 445000)
    (2 College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072)
  • Received:2004-10-26 Revised:2005-09-17 Published:2006-01-14
  • Contact: DAN You-Meng

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合成了高氯酸镨和咪唑(C3H4N2), DL-α-丙氨酸(C3H7NO2)混配配合物晶体. 经傅立叶变换红外光谱、化学分析和元素分析确定其组成为[Pr(C3H7NO2)2(C3H4N2)(H2O)](ClO4)3. 使用具有恒温环境的溶解-反应量热计, 以2.0 mol•L－1 HCl为量热溶剂, 在T＝(298.150±0.001) K时测定出化学反应PrCl3•6H2O(s)＋2C3H7NO2(s)＋C3H4N2(s)＋3NaClO4(s)＝[Pr(C3H7NO2)2(C3H4N2)(H2O)](ClO4)3(s)＋3NaCl(s)＋5H2O(1)的标准摩尔反应焓为ΔrHm?＝(39.26±0.11) kJ•mol－1. 根据盖斯定律, 计算出配合物的标准摩尔生成焓为ΔfHm?{[Pr(C3H7NO2)2(C3H4N2)(H2O)](ClO4)3(s), 298.150 K}＝(－2424.2±3.3) kJ•mol－1. 采用TG-DTG技术研究了配合物在流动高纯氮气(99.99%)气氛中的非等温热分解动力学, 运用微分法(Achar-Brindley-sharp和Kissinger法)和积分法(Satava-Sestak和Coats-Redfern法)对非等温动力学数据进行分析, 求得分解反应的表观活化能E＝108.9 kJ•mol－1, 动力学方程式为dα/dt＝2(5.90×108/3)(1－α)[－ln(1－α)]－1exp(－108.9×103/RT).

关键词: 稀土配合物, 溶解-反应量热, 标准生成焓, TG-DTG技术, 热分解动力学

The crystal of a mixed ligand complex of praseodymium perchlorate with imidazole (C3H4N2) and DL-α-alanine (C3H7NO2) was synthesized and characterized. The empirical formula of the crystal was determined to be [Pr(C3H7NO2)2(C3H4N2)(H2O)](ClO4)3 by FT-IR spectrum, chemical analysis and elemental analysis. The enthalpy of reaction of PrCl3•6H2O(s)＋2C3H7NO2(s)＋C3H4N2(s)＋3NaClO4(s)＝[Pr(C3H7NO2)2(C3H4N2)(H2O)](ClO4)3(s)＋3NaCl(s)＋5H2O(l) in 2.0 mol•L－1 HCl solvents was determined to beΔrHm?＝(39.26±0.11) kJ•mol－1 by a solution-reaction isoperibol calorimeter at T＝(298.150±0.001) K. According to Hess’s Law, the standard molar enthalpy of formation of the title complex was derived, ΔfHm?{[Pr(C3H7NO2)2(C3H4N2)(H2O)](ClO4)3(s), 298.150 K}＝(－2424.2±3.3) kJ•mol－1. The non-isothermal thermal decomposition kinetics of the complex in flow atmosphere of high purity nitrogen (99.99%) was studied by TG-DTG techniques. The non-isothermal kinetics parameters were analyzed by means of differential (Achar-Brindley-shap and Kissinger method) and integral (Satava-Sastak and Coats-Redfern methods) methods, respectively. The apparent activation energy of the thermal decomposition reaction was obtained to give: E＝108.9 kJ•mol－1, and the kinetic equation may be expressed as: dα/dt＝2(5.90×108/3)(1－α)[－ln(1－α)]－1exp(－108.9×103/RT).

Key words: complex of rare earth, solution-reaction calorimetry, standard enthalpy of formation, TG-DTG technique, thermal decomposition kinetics