希土异硫氰酸盐与二甲基乙酰胺配合物的热分析研究

THERMOANALYTICAL STUDIES ON THECOMPLEXES OF RARE EARTH ISOTHIOCYANATESWITH N.N-DIMETHYLACETAMIDE

本文利用TG-DTA-DTG技术对除了钪、钷以外的十五种希土异硫氰酸盐与二甲基乙酰胺的固体配合物进行了热分析研究。测定了它们的熔点和熔化热,分别用Doyle法和Kissinger法计算出各配合物热分解过程氧化反应的活化能,两种方法所得结果基本一致。实验发现镧系元素的该系列配合物的熔化热和热分解反应的活化能均随配合物中心离子—镧系元素原子序数的递增而呈现“双峰现象”。

Fifteen solid complexes of rare earth isothiocynatcs with N, N-dimethylacetamide have been studied by means of TG-DTA-DTG techniques. On the one hand , by DTA curves, using a heating rate 5℃ min-1,the melting points and the heats effusion for the complexes were determined; On the other hand,by TG and DTA curves with four different heating rates (10, 5, 2, 0.5℃ min-1),the activation energies of the processes of thermal decomposition of the complexes were calculated by the Doyle method and the Kissinger method respectively .The results obtained with the two methods may be considered to be consistent. From the plots of the heats of fusion and the activation energies of the complexes against the atomic number of lanthanide, 'double peak phenomenon' are observed.