A comparison of siliceous faujasitic zeolites produced by direct synthesis or by secondary synthesis

Journal Article · Wed Oct 30 23:00:00 EST 1991 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100175a075· OSTI ID:7141981

Dwyer, J; Karim, K; Smith, W J; Thompson, N E ^[1]; Harris, R K; Apperley, D C ^[2]

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1. UMIST, Manchester (United Kingdom)
2. Univ. of Durham (United Kingdom)

Synthetic cubic faujasites (Si/Al = 4) are synthesized hydrothermally and compared with (1) materials of similar framework composition produced by secondary synthesis from zeolite Y using silicon hexafluoride and (2) zeolite ZSM-20. Solid-state NMR ({sup 29}Si and {sup 27}Al), XRD, FTIR, and surface analysis are used to characterize the materials, which are also evaluated as catalysts by using n-hexane conversion as a test reaction. {sup 29}Si NMR results suggest that the materials produced by primary synthesis have aluminum ordering differing from that observed in materials with similar framework composition (Si/Al) but produced by secondary synthesis. The difference evident in the {sup 29}Si NMR may account for the higher catalytic activity observed with the products of direct synthesis. Surface analysis using depth profiling shows that the siliceous frameworks produced by direct synthesis are more homogeneous than materials produced by secondary synthesis.

• OSTI ID: 7141981
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 95:22; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020400 -- Petroleum-- Processing
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKANES
ALUMINIUM 27
ALUMINIUM ISOTOPES
CATALYTIC EFFECTS
CHEMICAL PREPARATION
COHERENT SCATTERING
DATA
DIFFRACTION
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
FAUJASITE
FOURIER ANALYSIS
HEXANE
HYDROCARBONS
HYDROTHERMAL SYNTHESIS
INFORMATION
INFRARED SPECTRA
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MATERIALS
MINERALS
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
RESONANCE
SCATTERING
SILICATE MINERALS
SILICON 29
SILICON ISOTOPES
SPECTRA
STABLE ISOTOPES
SYNTHESIS
X-RAY DIFFRACTION
ZEOLITES