This study shows that the MWW structure is more stable than previously known zeolites. Structural, thermal and spectroscopic analyses have shown that acid MCM-22 zeolite is stable up to 1373K under vacuum and to 1473K in air. The Brönsted hydroxyl groups withstand temperatures up to 1173K. At 1473K there is a phase transition from the MWW structure into α-cristobalite when the sample is under vacuum while for the sample treated in air only a small fraction of the total is transformed to α-cristobalite at 1473K.
The stability of H-MCM-22 under severe thermal conditions
BOCCALERI, Enrico;MARCHESE, Leonardo
2004-01-01
Abstract
This study shows that the MWW structure is more stable than previously known zeolites. Structural, thermal and spectroscopic analyses have shown that acid MCM-22 zeolite is stable up to 1373K under vacuum and to 1473K in air. The Brönsted hydroxyl groups withstand temperatures up to 1173K. At 1473K there is a phase transition from the MWW structure into α-cristobalite when the sample is under vacuum while for the sample treated in air only a small fraction of the total is transformed to α-cristobalite at 1473K.File in questo prodotto:
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