Synthesis, modification, and characterization of NH4 zeolites and their relationships to their hydrogen forms

沸石是最重要的一类材料，主要用作催化剂、吸附剂和离子交换剂。铵盐交换沸石是合成H型沸石的重要原料，是沸石催化剂的主要基团。我们在标准化的环境下汇编了5000多条沸石的晶体结构描述，使我们能够轻松地比较它们的晶体结构。我们的目标是通过单晶结构分析来表征铵交换沸石，并将NH4的晶体化学环境与我们数据库中包含的其他NH4沸石相关联。将特别关注氨在焙烧制备H-沸石催化剂中的作用。在这方面，将对选定的沸石的脱氨过程进行额外的实验。结果将与我们数据库中的结构数据相关联，从而对NH4沸石中的氢键方案进行完整的分析，对H沸石的骨架柔性进行比较分析，并重新确定沸石中NH4离子的离子半径。将通过X射线粉末和单晶衍射、透射电子显微镜、带有EDX附件的扫描电子显微镜、红外光谱和固体核磁共振光谱来进行表征。用中子衍射法研究分子筛中的氢交换形式。

Zeolites belong to the most important classes of materials with main applications as catalysts, adsorbants, and ion exchangers. Ammonium exchanged zeolites play an important role as precursor materials in the production of H-zeolites representing the main group of zeolite catalysts. We have compiled more than 5,000 entries of crystal-structure descriptions of zeolites in standardized settings which enables us to easily compare their crystal structures. It is our aim to characterize ammonium exchanged zeolites by single-crystal structure analyses and to correlate the crystal-chemical environment of NH4 with other NH4 zeolites contained in our database. A special focus will be on the role of ammonium upon calcination to make the H-zeolite catalysts. In this context additional experiments will be performed on the deammoniation process of selected zeolites. The results will be correlated with the structural data in our database, leading to a complete analysis of hydrogen bonding schemes in NH4 zeolites, to a comparative analysis of framework flexibilities of H-zeolites, and to a redetermination of the ionic radius of the NH4 ion in zeolites. Characterization will be done by X-ray powder and single-crystal diffraction, transmission electron microscopy, scanning electron microscopy with EDX attachment, IR spectroscopy, and solid state NMR spectroscopy. Deuterium exchanged forms of zeolites will be studied by neutron diffraction methods.