Strucral analysis of SDA-containing zeolites for the elucidation of zeolite crystallization mechanism

分析了含SDA沸石的晶体结构，以提取SDA分子结晶沸石的特定结构的要求。采用几种具有相似结构特征的有机SDA合成具有小骨架的LEV型沸石，并使用X射线粉末衍射数据分析所获得的沸石。分析结果表明，SDA分子被封闭在一个lev笼中，并与lev笼中的氧原子在它们的货车德瓦尔斯半径处相切，这是SDA分子的尺寸要求。具有较大分子尺寸的SDA得到具有较大cha笼的CHA型沸石。考虑到这两种沸石可以由相同的结构单元构成，这些沸石的骨架可以由相同的结构单元构成，SDA的大小可以决定沸石的最终相。

The crystal structure of SDA-containing zeolites were analyzed in order to extract a requirement for an SDA molecule to crystallize a certain structure of zeolite. Several organic SDAs having a similar structural feature were employed to synthesize LEV-type zeolites having a small lev cage, and the obtained zeolites were analyzed using X-ray powder diffraction data. The analysis results demonstrated that an SDA molecule was occluded in a lev cage and was tangent to an oxygen atom in lev cage in their van der Waals radii, which would be a size requirement for an SDA. SDAs with larger molecular sizes gave CHA-type zeolite having a larger cha cage. Considering that these two zeolites can be constructed from the same building unit, the framework of these zeolites could be constructed from the same building unit, and the size of SDA could decide the resulting phase of zeolite.