Solid-state NMR studies of framework defects in thermally treated zeolite Ca-A
1987; Elsevier BV; Volume: 133; Issue: 6 Linguagem: Inglês
10.1016/0009-2614(87)80065-9
ISSN1873-4448
AutoresD. Freude, Jürgen Haase, Jacek Klinowski,
Tópico(s)Zeolite Catalysis and Synthesis
ResumoAbstract 29 Si, 27 Al and 1 H magic-angle-spinning NMR and relaxation measurements on thermally treated zeolite Na 3.2 Ca 4.4 -A have been carried out in order to study framework defects responsible for, and surface barriers to, molecular diffusion. Various possible mechanisms for the formation of such defects are considered in detail. We conclude that no framework dealumination takes place and no acidic hydroxyl groups are present in the zeolite. Excess aluminium occluded in the as-prepared zeolite A is responsible for the production of aluminium hydroxide during hydrothermal treatment.
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