Knoevenagel reaction spectroscopy

The very first report on the use of ionic liquids as soluble supports was presented by Fraga-Dubreuil and Bazureau in 2001 [102]. The efficacy of a microwave-induced solvent-free Knoevenagel condensation of a formyl group on the ionic liquid (IL) phase with malonate derivatives (E1CH2E2) catalyzed by 2 mol% of piperidine was studied (Scheme 7.89). The progress of the reaction could be easily monitored by 1H and 13C NMR spectroscopy, and the final products could be cleaved from the IL... 

In previous papers we demonstrated that the same nitridation approach can be also successfully applied for the incorporation of nitrogen into the framework of different Y zeolites, this making possible the preparation of porous basic catalysts active in the Knoevenagel condensation reaction [13-14]. The present work was undertaken in order to understand the modifications induced by nitridation and to provide a picture of the chemical rearrangements that occur upon nitrogen incorporation into ultrastable Y zeolite (Si/Al ratio of 13). Since catalysis is a surface phenomenon we choose to characterize the local environments of nitrogen, silicon and aluminum by X-ray photoelectron spectroscopy (XPS). A clear identification of these modifications is essential to allow a control of the preparation parameters for more efficient basic catalysts. 

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