作者:E. Mikuli、M. Liszka、M. Molenda
DOI:10.1007/s10973-006-7610-6
日期:2007.8
Thermal decomposition of [Cd(NH3)6](NO3)2 was studied by thermogravimetry (TG) with simultaneous differential thermal analysis (SDTA) for two samples and at two different sets of measurement parameters. The gaseous products of the decomposition were on-line identified by evolved gas analysis (EGA) with a quadruple mass spectrometer (QMS). The decomposition of the title compound proceeds, for both cases, in the three main stages. In the first stage, deammination of [Cd(NH3)6](NO3)2 to [Cd(NH3)](NO3)2 undergoes by three steps and 5/6 of all NH3 molecules are liberated. At second stage the liberation of residual 1/6NH3 molecules and the formation of Cd(NO3)2 undergoes. However, during this process simultaneously a two-step oxidation of a part of ammonia molecules also takes place. In a first step as a result a mixture of ammonia, water vapour and nitrogen is formatted. At the second step, subsequent oxidation of a next part of NH3 molecules undergoes. As a result, a mixture of nitrogen oxide, nitrogen and water vapour is formatted, what for these both steps clearly indicates the EGA analysis. The third stage of the thermal decomposition is connected with the melting and subsequent decomposition of residual Cd(NO3)2 to oxygen, nitrogen dioxide and solid CdO. Additionally, third sample was measured by differential scanning calorimetry (DSC) and the results are fully consistent with those obtained by TG.
通过热重分析法(TG)和同步微分热分析法(SDTA)研究了[Cd(NH3)6](NO3)2 在两种样品和两组不同测量参数下的热分解。分解产生的气体产物通过四重质谱仪(QMS)的气体分析(EGA)进行在线鉴定。在这两种情况下,标题化合物的分解过程分为三个主要阶段。在第一阶段,[Cd(NH3)6](NO3)2 通过三个步骤脱氨成 [Cd(NH3)](NO3)2,所有 NH3 分子中有 5/6 被释放出来。在第二阶段,剩余的 1/6NH3 分子被释放出来,形成 Cd(NO3)2。不过,在这一过程中,部分氨分子也同时进行了两步氧化。第一步的结果是形成氨、水蒸气和氮的混合物。在第二步中,下一部分的 NH3 分子随后发生氧化。结果形成了氧化氮、氮气和水蒸气的混合物,这两个步骤清楚地表明了 EGA 分析的结果。热分解的第三阶段与残余 Cd(NO3)2 的熔化和随后分解为氧气、二氧化氮和固体 CdO 有关。此外,还用差示扫描量热法(DSC)对第三个样品进行了测量,结果与 TG 得出的结果完全一致。