固体高分解能 NMR によるゼオライトのキャラクタリゼーション

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The unique catalytic and adsorbent properties, crystal structures, ion-exchange and other characteristics of zeolites have been extensively investigated in recent years. The high-resolution solid-state ^<29>Si- and ^<27>Al-nuclear magnetic resonance (NMR) with magic angle spinning (MAS) have proved to be an useful tool for the chemical structural characterization of zeolites. The article reviews how high-resolution solid-state NMR with MAS reveals unique insights into zeolite structures from recent literatures. Since five distinct Si-Al confrgurations. Si (OAl)_n (OSi)_<4-n> (n=0〜4), in zeolitic frameworks can be identified by ^<29>Si-MAS NMR. several interesting problems have been enthusiastically discussed on ^<29>Si-NMR analysis. In the present paper, the following topics are introduced and discussed : (1) Assignments of ^<29>Si-chemical shifts arid Si-Al configurations for aluminosilicates. (2) Discussion of Loewenstein's rule, the presence of Al-O-Al ordering, in the zeolite A. (3) Characteristic changes of Si/Al ratio in faujasites (zeolites X and Y) and mordenite studied by ^<29>Si-NMR spectra. (4) ^<29>Si-NMR spectral studies on the framework structures of pentasil zeolites such as ZSM-5 ZSM-11 and silicalite. (5) Stuidies of Ga^<3+> substrtution for Al<3+> in the zeolitic frameworks of faujasites studied by ^<29>Si-NMR spectra. (6) Other ^<29>Si-NMR spectral studies on zeolitic framework. On the other hand, ^<27>Al-NMR has been used to estimate the compositions on tetrahedrally and octahedrally coordinated aluminum states. For instance. the dealumination mechanisms have been investigated by the ^<27>Al-NMR spectral behaviors. Furthermore the application of high-resolution solid-state ^<13>C-NMR to the characteristic. changes of organic compounds, in the zeolitic frameworks has been discussed.
日本粘土学会の論文
1984-09-01

固体高分解能 NMR によるゼオライトのキャラクタリゼーション

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