Synthesis of Large-Sized Sapo-5 Crystals With Silicon Occupying Predominantly Phosphorus-T-Sites
✍ Scribed by G. Finger; E. Jahn; D. Zeigan; B. Zibrowius; K. Szulzewsky; J. Richter-Mendau; M. Bülow
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 2010
- Weight
- 271 KB
- Volume
- 98
- Category
- Article
- ISSN
- 0037-9646
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✦ Synopsis
Silicoaluminophosphates of type SAPO-5 with low content of silicon have been synthesized forming single hexagonal prisms up to 100 micrometers. By 293 MAS NMR technique it is proved that in these samples silicon predominantly occupies framework sites which should give rise to catalytic activity.
Silicoaluminophosphates (SAPOs) /I/ are related to microporous aluminophosphates (ALPOs) /2/ of analogous really existing or hypothetical structural types but containing silicon substituting partially T-atoms. Various mechanisms of substituting the T-atoms by silicon have been discussed /I/. The synthesis of SAPOs is claimed in numerous patents, the first published in 1984 /3/. However, details how to influence both the crystal morphology and the crystal size are scarcely published. Molecular sieves of AFI structure, i.e. ALPO-5 and SAPO-5, are mostly synthesized as fine powders forming either barrel-like growth aggregates or small hexagonal prisms /3-7/. Electron micrographs of hexagonal ' '