Synthesis, characterization and reactivity of transition-metal-containing zeolites
Transition metal containing zeolites (zeolite A and ZSM-5) were prepared by addition of various transition metal containing substrates to zeolite synthesis gels. Crystal growth data were recorded in order to determine the influence of the transition metal species on the rate of crystal growth. X-ray diffraction, oxygen adsorption, FTIR and SEM were utilized to evaluate crystal purity. X-ray photoelectron spectroscopy (XPS), chemical analysis and electron microprobe analysis were performed in order to ascertain the position (intrazeolitic versus surface) and homogeneity of the transition metal. It was concluded that intrazeolitic transition metals are produced by the novel procedure presented in this work. 1-Hexane hydroformylation by rhodium zeolite A showed intrazeolitic rhodium to migrate to the external surface of the zeolite. However, in the presence of a solution and surface rhodium poison, intrazeolitic rhodium was found to hydroformylate 1-hexene exclusively to heptanal. Ruthenium containing zeolite A was evaluated under CO-hydrogenation conditions. No migration of intrazeolitic ruthenium to the external surface of the zeolite was observed over the course of the reaction. The product distribution obtained for this catalyst did not follow a log normal behavior. Also, loss of zeolite crystallinity was observed following the reaction. Cobalt ZSM-5 was evaluated under CO-hydrogenation conditions. No migration of cobalt to the external surface of the zeolite occurred. XPS analysis of the catalyst following various stages of the reaction indicated that intrazeolitic cobalt was not reduced to the zero valent state. Consequently, the non-zero valent cobalt was not capable of hydrogenating carbon monoxide.
- Research Organization:
- Virginia Polytechnic Inst. and State Univ., Blacksburg (USA)
- OSTI ID:
- 6915740
- Country of Publication:
- United States
- Language:
- English
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ADSORPTION
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSIS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL PREPARATION
CHEMICAL REACTIONS
COBALT
COHERENT SCATTERING
CRYSTAL GROWTH
DIFFRACTION
ELECTRON MICROPROBE ANALYSIS
ELECTRON MICROSCOPY
ELECTRON SPECTROSCOPY
ELEMENTS
FISCHER-TROPSCH SYNTHESIS
FOURIER TRANSFORMATION
HYDROGENATION
INFRARED SPECTRA
INORGANIC ION EXCHANGERS
INTEGRAL TRANSFORMATIONS
ION EXCHANGE MATERIALS
MATERIALS
METALS
METHANATION
MICROANALYSIS
MICROSCOPY
MINERALS
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
PLATINUM METALS
RHODIUM
RUTHENIUM
SCANNING ELECTRON MICROSCOPY
SCATTERING
SORPTION
SPECTRA
SPECTROSCOPY
SYNTHESIS
TRANSFORMATIONS
TRANSITION ELEMENTS
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY
ZEOLITES