Abstract:
The i.r. absorption curve of “ deep bed ” calcined NH4Y zeolites could be broken down into
the same components as HY zeolites. The frequency of the peaks was slightly changed, but their
half band width remained constant. In a scries of treatments representing increasing hydrolysis
non-acidic OH bands around 3680 and 3600 cm-1 increase in intensity, due to surface OH groups
near Al defect locations. Polynuclear Al species bridging the cubo-octahcdra are suggested to be
partly responsible for the increased thermal stability. The non-acidic OH bands in synthetic
faujasites exchanged with polyvalent cations are explained on the same basis, since they behave in a
similar way as the non-acidic bands on “ deep bed ” zeolites after different treatments.
