Preparation and characterization of new basic catalysts by nitridation of Y zeolites

In recent years, the base-catalyzed reactions play a more and more important role in modern fine chemicals, nonetheless reports about solid base catalysts are still far fewer than that of solid acid catalysts. Therefore, new solid base catalysts are imminently desirable to meet the need of the fine chemical industry. In the nineties, it was found that nitrogen incorporation is an effective way to synthesize new solids basic materials. Through treating various amorphous oxides with flowing ammonia at high temperatures "nitridation", a new family of heterogeneous basic catalysts was made. In the present work we demonstrated that the same "nitridation" approach can be also successfully applied for the incorporation of nitrogen into the framework of Y zeolites and therefore the preparation of porous basic catalysts. The nitrogen content of the nitride zeolites can be adjusted by varying both temperature and nitridation time. Furthermore, the nitridation temperature can influence also the nature of nitrogenous species into the zeolitic framework. The following species were identified by DRIFT spectroscopy and XPS: NH4+, NH3ads, -NH2, >NH and >N-. The presence of nitrogen into the zeolitic framework induced modifications in both aluminum and silicon environments. The evaluation of the catalytic properties of the nitrided zeolites in the Knoevenagel condensation reaction between benzaldehyde and malononitrile revealed that the activity of the zeolites is deeply improved by nitrogen incorporation as long as the zeolitic framework was maintained.Doctorat en sciences agronomiques et ingénierie biologique (AGRO 3)--UCL, 200