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

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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.