Defect Models of As-Made High-Silica Zeolites: Clusters of Hydrogen-Bonds and Their Interaction with the Organic Structure-Directing Agents Determined from 1H Double and Triple Quantum NMR Spectroscopy
Defect Models of As-Made High-Silica Zeolites: Clusters of Hydrogen-Bonds and Their Interaction with the Organic Structure-Directing Agents Determined from 1H Double and Triple Quantum NMR Spectroscopy
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DOI：
10.1002/anie.201607428
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发表时间：
2016-11-07
影响因子：
16.6
通讯作者：
Zones, Stacey I.
中科院分区：
文献类型：
--
作者：
Brunklaus, Gunther;Koller, Hubert;Zones, Stacey I.
在阳离子有机结构导向剂（SDA）存在下，高硅沸石结构形成过程中，内部缺陷SiOH和SiO-基团的形成。这些带负电荷的缺陷在煅烧时不会完全消失。在这里，我们研究了四种沸石孔壁内的缺陷基团的聚集和它们的位置。ZSM-12、ZSM-5和SSZ-74具有三个与SiO-氢键合的成簇SiOH基团，而SSZ-24仅具有两个。这些缺陷与结构导向的季铵离子相互作用，优选靠近电荷中心，除非存在空间屏蔽。ZSM-12、ZSM-5和SSZ-24的骨架拓扑结构具有连接的六环，其中有机物与缺陷相互作用。有人认为这些六环图案形成了连接缺陷。SSZ-74是独特的，它不包含扩展的六环基序，因此形成空位缺陷。
Internal defect SiOH and SiO- groups evolve during the structure formation of high-Si zeolites in the presence of a cationic organic structure-directing agent (SDA). These negatively charged defects do not completely disappear upon calcination. Herein we investigate the clustering of defect groups and their location within the pore walls of four zeolites. ZSM-12, ZSM-5, and SSZ-74 have three clustered SiOH groups which are hydrogen-bonded to SiO-, whereas SSZ-24 has only two. These defects interact with the structure-directing quaternary ammonium ions preferably close to the charge center, unless steric shielding is present. The framework topologies of ZSM-12, ZSM-5, and SSZ-24 have connected six-rings where the organics interact with the defects. It is suggested that these six-ring patterns form connectivity defects. SSZ-74 is unique, it does not contain an extended six-ring motif, so vacancy defects form instead.