Characterization of aluminophosphate surfaces via sup 29 Si CP/MAS NMR (cross polarization/magic angle spinning nuclear magnetic resonance)
- Phillips Research Center, Bartlesville, OK (USA)
The {sup 29}Si CP/MAS spectra of the reaction products of hexamethyldisilazane (HMDS) with porous aluminophosphates showed distinct resonances from trimethylsiloxane groups attached to both aluminum and phosphorus. The relative intensity of the two signals varied according to the composition of the carrier; however, integration always indicated a higher phosphorous to aluminum ratio in the silane product than expected from the bulk composition. This can be explained by either a nonhomogeneous distribution of phosphorus and aluminum centers or a hindered reaction mechanism at the surface. In either case, the reaction products of HMDS with the aluminophosphate surface can be used to predict the behavior of other substrates at this surface, such as catalytically active chromium compounds. The spectra of the reaction products obtained with dichlorodimethylsilane suggest not only dimethylsiloxane groups bridging aluminum/phosphorus centers but also phosphorus/phosphorus and aluminum/aluminum bridges.
- OSTI ID:
- 6835820
- Journal Information:
- Journal of Catalysis; (USA), Vol. 115:2; ISSN 0021-9517
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALUMINIUM PHOSPHATES
SURFACE PROPERTIES
CATALYSTS
NUCLEAR MAGNETIC RESONANCE
CATALYTIC EFFECTS
CHEMICAL REACTIONS
DISTRIBUTION
MICROSTRUCTURE
POROSITY
QUANTITY RATIO
SILANES
SILICON 29
SILOXANES
ALUMINIUM COMPOUNDS
CRYSTAL STRUCTURE
EVEN-ODD NUCLEI
HYDRIDES
HYDROGEN COMPOUNDS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
NUCLEI
ORGANIC COMPOUNDS
ORGANIC SILICON COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
RESONANCE
SILICON COMPOUNDS
SILICON ISOTOPES
STABLE ISOTOPES
400101* - Activation
Nuclear Reaction
Radiometric & Radiochemical Procedures
400201 - Chemical & Physicochemical Properties