Iron oxide pillared clay with large gallery height: Synthesis and properties as a Fischer-Tropsch catalyst
- Michigan State Univ., East Lansing (USA)
New iron oxide pillared montmorillonites have been prepared by the reaction of Na{sup +} montmorillonite with base-hydrolyzed solutions of Fe{sup 3+} salts and subsequent thermal conversion of the intercalated polycations. Depending on the hydrolysis conditions used to generate the pillaring solutions, pillared products with basal spacings in the range 18 to 25 {angstrom} were obtained. Under optimum hydrolysis conditions (base/metal = 2.0 meq/mol, aging time = 23-147 hr) the pillared products contained 6.8-9.8 Fe{sup 3+} ions per O{sub 20}(OH){sub 4} unit cell and exhibited basal spacings of 25-29 {angstrom}. These latter spacings corresponded to exceptionally large gallery heights of 15-19 {angstrom}. Upon calcination at 300C, the spacings decreased to 23-27 {angstrom}. N{sub 2} BET surface areas after outgassing at 350C were in the range 270 to 350 m{sup 2}/g. The pillared products are active catalysts that have undergone Fischer-Tropsch synthesis of hydrocarbons at 275 C and 120 {minus}psi (CO:H{sub 2}=1:2). The hydrocarbon distribution in the C{sub 1}-C{sub 6} range (1.3% conversion) followed Anderson-Schulz-Flory statistics with a chain propagation probability of {alpha} = 0.49. X-ray energy dispersive analysis indicated that substantial amounts of the intercalated iron migrated to the edge sites of the clay particles under reaction conditions. The redistribution of iron resulted in a distribution of gallery heights sufficiently heterogeneous to preclude Bragg X-ray scattering along the 001 direction. Iron migration also occurred upon exposure of the pillared products to the ambient atmosphere for prolonged periods ({ge}3 months).
- OSTI ID:
- 5454269
- Journal Information:
- Journal of Catalysis; (United States), Vol. 130:1; ISSN 0021-9517
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CATALYSTS
CHEMICAL PREPARATION
FISCHER-TROPSCH SYNTHESIS
IRON OXIDES
CATALYTIC EFFECTS
PHYSICAL PROPERTIES
MONTMORILLONITE
AIR
ALCOHOLS
BRAGG REFLECTION
CALCINATION
CARBON MONOXIDE
CATALYTIC CRACKING
CRYSTAL STRUCTURE
DEHYDROGENATION
DISTRIBUTION
HYDROCARBONS
HYDROGENATION
HYDROLYSIS
LOADING RATE
METHANATION
MOLECULAR WEIGHT
SURFACE AREA
X-RAY SPECTROSCOPY
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CLAYS
CRACKING
DECOMPOSITION
FLUIDS
GASES
HYDROXY COMPOUNDS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
IRON COMPOUNDS
LYSIS
MATERIALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PYROLYSIS
REFLECTION
SOLVOLYSIS
SPECTROSCOPY
SURFACE PROPERTIES
SYNTHESIS
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS
010408* - Coal
Lignite
& Peat- C1 Processes- (1987-)
400201 - Chemical & Physicochemical Properties