Theoretical and experimental study on the thermal stability of three dimensional zeolite framework

研究了三维沸石骨架的计算机模拟及其热稳定性。(1)为了表征和构建各种沸石骨架。应用了基于图论的同心簇概念。给出了三维骨架的系统推导。(2)通过引入替代节点矩阵法实现了硅、铝在沸石骨架上的分布。这也使得对观测到的核磁共振谱进行理论估算和研究Dempsey规则的正确性成为可能。(3)应用分子动力学模拟可以测试沸石骨架的热稳定性。根据它，稳定性对骨架的拓扑结构影响不大，但对骨架中的Si/Al含量有显著的影响。在计算机模拟中，部分离子模型比完全离子模型更接近真实的骨架。这种模拟需要更合适的势能模型和参数。

Computer modelling of three dimensional zeolite frameworks and their thermal stability are invetigated.(1) In order to charcterize and construct various kinds of zeolite frameworks. the CCL (Concentric cluster) concept based onthe graph theory is applied. Sytematical derivation of three dimensional framework is shown.(2) Si and Al distributions on zeolite frameworks are realized by an introduction of substituted node matrix method. This also enables theoretical estimation of observed NMR spectrum and the investigation of validity of Dempsey's rule.(3) Thermal stability of zeolite frameworks can be tested by application of Molecular Dynamic simulation. According to it, the stability is not so effected on the framewrk topology, but on the Si/Al contents remarkably in the framework. The encapusulation of extra anions is effective for the promotion of framework stability.(4) In the computer simulation, the partial ionic model is more fitted on the real framework than the complete ionic model. More suitable potential models and parameters are needed for this kind of simulation.