物理化学学报 >> 2005, Vol. 21 >> Issue (09): 1001-1005.doi: 10.3866/PKU.WHXB20050912

研究论文 上一篇    下一篇

MC2O4(M=Mn、Fe、Co、Ni、Cu、Zn)的热力学及其热分析动力学

闪海威; 陈栋华; 唐万军   

  1. 中南民族大学化学与材料科学学院, 催化材料科学湖北省重点实验室, 武汉 430074
  • 收稿日期:2005-01-17 修回日期:2005-03-17 发布日期:2005-09-15
  • 通讯作者: 陈栋华 E-mail:chendh46@sina.com

Thermodynamics and Thermal Analysis Kinetics of MC2O4 (M=Mn, Fe, Co, Ni, Cu, Zn)

SHAN Hai-wei CHEN Dong-hua TANG Wan-jun   

  1. Hubei Key Laboratory for Catalysis and Material Science, College of Chemistry and Material Science, South-Central University for Nationalities, Wuhan 430074
  • Received:2005-01-17 Revised:2005-03-17 Published:2005-09-15
  • Contact: CHEN Dong-hua E-mail:chendh46@sina.com

摘要: 用DSC、TGA技术分别在N2气氛和O2气氛下对MC2O4(M=Mn、Fe、Co、Ni、Cu、Zn)的脱水和分解过程作了热力学和动力学的研究. 在N2气氛下, MC2O4•2H2O(M=Mn、Fe、Co、Ni、Zn)脱水温度Tde和脱水焓ΔdeHm随原子序数Zre递增呈现明显的“二分组效应”;ΔdeHm在(96.46±7.00) kJ•mol-1范围内波动;MC2O4•2H2O (M=Mn、Fe、Ni)的分解温度Td随原子序数递增呈现良好的线性关系;且各草酸盐分解得到氧化物(CuC2O4生成Cu、CuO混合物)时, MC2O4(M=Co、Ni、Cu) 分解焓随原子序数增大也存在良好的线性关系. 各草酸盐除NiC2O4•2H2O脱水过程和FeC2O4分解过程外, 其余各过程机理函数均为随机成核和随后成长型.

关键词: 差示扫描量热法, 热重, 草酸盐, 过渡元素, 原子序数, 热力学, 热分析动力学

Abstract: Thermodynamics and Kinetics of MC2O4 (M=Mn, Fe, Co, Ni, Cu, Zn) were studied in N2 or O2 using DSC and TGA techniques. In N2, the dehydration temprature Tde and enthalpy of dehydration ΔdeHm show “Two Group Domino Effect” along with atomic number Zre;ΔdeHm fluctuates in the range of (96.46±7.00) kJ•mol-1;the decomposition temperature Td of MC2O4•2H2O (M=Mn, Fe, Ni) and enthalpy have very good linearity along with atomic number Zre. When forming oxide MO in oxygen, decomposition enthalpy of MC2O4 (M=Co, Ni, Cu) shows a beeline along with atomic number Zre. All the reactions, except the dehydration of NiC2O4•2H2O and the decomposition FeC2O4, belong to the same mechanism of random nucleation and growth, with integral form , and differential form .

Key words: DSC, TG, Oxalate, Transition elements, Atom number, Thermodynamics, Thermal analysis kinetics