Carbon monoxide hydrogenation and propylene conversion over palladium-impregnated ZSM-5 and SAPO (silicoaluminophosphate) molecular sieves

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5004771

Thomson, R T

The catalytic properties of ZSM-5 and SAPO molecular sieves, studied during CO hydrogenation over Pd/ZSM-5 and Pd/SAPO catalysts and during propylene conversion over ZSM-5 and SAPO catalysts, have been correlated with their physico-chemical characteristics, as determined by infrared spectroscopy, ammonia desorption experiments, and electron microscopy. While Na and La cations enhanced the CO hydrogenation activity of the Pd sites, Pd/NaZSM-5 yielded primarily oxygenates (methanol and dimethyl ether), while Pd/HZSM-5 and Pd/LaZSM-5 catalyzed the formation of light alkanes and polymethylbenzenes. Synthesis of C{sub 2}+ hydrocarbons from syngas occurred through a bifunctional pathway, which included methanol synthesis followed by conversion on strong acid sites within the ZSM-5 micropores. A similar route accounted for the formation of C{sub 2}+ alkanes during CO hydrogenation over Pd-impregnated SAPO molecular sieves. For both Pd/ZSM-5 and Pd/SAPO catalysts, the rate of olefin hydrogenation and the characteristics of the molecular sieves played an important role in determining the product distribution. The physical and chemical properties of ZSM-5 and SAPO molecular sieves were also compared to their activity for propylene conversion. ZSM-5 catalysts possessing strong acid sites yielded the most products, primarily of C{sub 4}-C{sub 7} olefins. SAPO molecular sieves, showing significantly less activity than the ZSM-5 catalysts, deactivated quickly. Mass transfer phenomena influenced the rate of catalyst deactivation as well as the product distribution over SAPO-5 and SAPO-34. Trends observed during propylene conversion were directly related to specific structural or chemical properties of the molecular sieves.

• Research Organization: Notre Dame Univ., IN (USA)
• OSTI ID: 5004771
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010400* -- Coal
Lignite
& Peat-- Processing
02 PETROLEUM
020400 -- Petroleum-- Processing
ADSORBENTS
ALCOHOLS
ALKALI METALS
ALKENES
ALUMINIUM COMPOUNDS
AMMONIA
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYTIC EFFECTS
CATALYTIC REFORMING
CHALCOGENIDES
CHEMICAL PROPERTIES
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
CONVERSION
CORRELATIONS
CRYSTAL STRUCTURE
DEACTIVATION
DESORPTION
ELECTRON MICROSCOPY
ELEMENTS
HEXENES
HYDRIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROGENATION
HYDROXY COMPOUNDS
INFRARED SPECTRA
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
KINETICS
LANTHANUM
MASS TRANSFER
MATERIALS
METALS
METHANATION
METHANOL
MICROSCOPY
MICROSTRUCTURE
MINERALS
MOLECULAR SIEVES
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PALLADIUM
PARTICLE SIZE
PH VALUE
PHOSPHATES
PHOSPHORUS COMPOUNDS
PHYSICAL PROPERTIES
PLATINUM METALS
POROSITY
PROPYLENE
RARE EARTHS
REACTION KINETICS
REFORMER PROCESSES
SILICON COMPOUNDS
SIZE
SODIUM
SPECTRA
SPECTROSCOPY
SYNTHESIS
TRANSITION ELEMENTS
YIELDS
ZEOLITES