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

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.

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

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 .