6533b872fe1ef96bd12d2d9e
RESEARCH PRODUCT
The synthesis of zeolites from dry powders
R. AlthoffR. AlthoffS. ReitmaierS. ReitmaierWolfgang SchmidtWolfgang SchmidtWolfgang SchmidtFerdi SchüthFerdi SchüthFerdi SchüthKlaus K. UngerKlaus K. UngerBodo ZibrowiusBodo ZibrowiusBodo Zibrowiussubject
Chemical engineeringChemistryVapor pressureReagentMass transferPhase (matter)Organic chemistryDeposition (phase transition)ZeoliteWater contentAmorphous soliddescription
Summary ZSM-5 was synthesized by different methods with a gradually decreasing water content ending in a reaction mixture with absolutely dry reagents in form of a powder in the complete absence of a solution phase. Amorphous precursors obtained by drying SiO 2 * Al 2 O 3 gels at 650°C were transformed into zeolites in the presence of dried NH 4 F and TPABr. The reaction products were characterized by XRD, REM, TG/DTA, MAS NMR and Electron Micropobe. Pure ZSM-5 or Silicalite-1 was obtained in all cases. Some water is probably formed as a reaction product, but the maximum water pressure is appreciably below the saturation pressure at the given reaction conditions. To explain the formation of a zeolite, we suggest a vapor phase mass transfer process with SiF 4 as the mobile species between the solid phase which contains the amorphous Si/Al-precursor and the formed zeolite.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1995-01-01 |