MULTINUCLEAR MAGNETIC RESONANCE CHARACTERIZATION OF SOLID CATALYSTS AND THEIR REACTIONS IN THE ADSORBED STATE

摘要

The high resolution magic angle spinning solid state Nuclear Magnetic Resonance has opened new horizons in the characterization of solid catalysts. Moreover, the strongly or covalently adsorbed molecules as reactants, intermediates or products can be easily detected and characterized. The present authors have already published several review papers on the study of the reactions in the adsorbed state using mainly ~(13)C NMR. On the other hand, the characterization of zeolitic materials before, during and after the hydrothermal synthesis allowed one to get a deep insight in the mechanism of formation of these microporous materials. Emphasis was also put on the characterization of various atoms which isomorphously substituted silicon in a tetrahedral form in the framework. The present paper contains both already published as well as original materials. It will be shown that more than four boron per unit cell can be introduced in the MFI zeolitic framework using fluoride-containing synthesis media. The siting of aluminium atoms will be tempted using ~(29)Si NMR and both ID ~(27)A l NMR and 2D MQ MAS ~(27)A1 NMR. Multi NMR characterization of both the solid phase and the adsorbed molecules will provide a rather complete understanding on the reaction of chlorofluorocarbons with zeolites and alumina. Finally, the reaction of ~(13)C labeled methanol will be presented on levyne catalysts.