Basicity in Alkali Cation-exchanged Zeolites

on the other hand, the Knoevenagel condensation is performed between benzaldehyde and a series of methylenic compounds with different pKa values, 

NaY faujasite has been also exchanged with Ca, La, Ce, and Re, and a systematic and comparative study of their catalytic activity in the Knoevenagel condensation between benzaldehyde and malononitrile has been conducted by Reddy et al. [63]. Two of the catalysts. La (70%) NaY and Ce (70%) NaY afforded moderate yields but rare-earth (Re)-exchanged NaY was found to be the optimum zeolite for this condensation in terms of yield, mass balance, and selectivity. 

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