气相色谱法研究负载型稀土醋酸配位化合物的热稳定性

Therml Stabilities of Lanthanones Acetates by the Use of Gas Chromatography

本文以程序升温一气相色谱法研究以MgO,SiO_2及γ-Al_2O_3作载休的负载型稀土醋酸盐及其相应纯盐在氢气中的热分解行为。实验结果表明稀土醋酸盐在H_2中的热分解反应可以分为三个阶段:1.释放出丙酮;2.释放出丙酮,二氧化碳,并形成Ln_2O_3及Ln_2O_3·CO_2;3.生成CO。 在载体作用下,稀土醋酸盐的分解温度降低,其中性载体SiO_2的影响较小,MgO载体使稀土醋酸盐分解温度明显降低。从Y,La到Pr随着稀土离子离子势增加载体的作用反而减小,但从Pr到Nd、Sm、Er随着稀土离子势的增加载体的作用又增强,所有三种载体对醋酸谱的影响均小。

The decomposition of Ln(CH3COO)3(Ln = La, Nd, Pr, Sm, Er, ) supported on MgO, SiO2, A12O3 and the corrosponding unsupported compounds in hydrogen atmosphere has been investigated by the use of gaschromatography.The decomposition products contain not only CO2, CH3COCH3 and C, but also a little CO during the reaction. Experimental results show that the decomposition of lanthanide acetates in H2 atmosphere takes place in three steps. (1) release of acetone; (2) release of CO2, CO, CH3COCH3, Ln2O3CO3 and Ln2O3 .(3)Formation of CO.It is found that the thermal decomposition of supported species is different from that of the unsupported compounds. The interaction of the compounds with MgO, Al2O3, SiO2 lowers the temperature of decomposition of the compounds.The effect of SiO2 on the compounds is less marked than of A12O3 and MgO. The effect of MgO on the compounds is most marked among the carriers. However, all the supports make litle effect on Pr(CH3COO)3. For lanthanide acetates before Pr, the effect of the carriers is decreased with the increasing of the ionic potential of the metal, but after Pr, that is increased with the increasing of the ionic potential of the metal.