Hydrodesulfurization and hydrogenation over sulfided ruthenium catalysts

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:5498790

Kuo, Y J

Mild presulfidization of ruthenium catalysts in 10% H/sub 2/S/H/sub 2/ at T less than or equal to 673K or in 100% H/sub 2/S at T less than or equal to 523K resulted in the formation of submonolayers of surface sulfur (S/Ru/sub (s)/ < 0.5), which were directly evident from microgravimetry and XPS and indirectly evident from XTD studies. It was further supported by pulse O/sub 2/ chemisorption data in which a S/Ru/sub (s)/ ratio of ca. 0.25 was obtained. Following mild presulfidization, both 1-hexene hydrogenation and thiophene hydrodesulfurization (HDS) were well represented by Langmuir-Hinshelwood rate equations. 1-Hexene hydrogenation over clean Ru surfaces appeared facile, whereas following sulfidization, the specific rates decreased one to two orders of magnitude depending on the Ru crystallite size. O/sub 2/ chemisorption data suggested that facile 1-hexene hydrogenation may have been still operative following sulfidization. A two-fold increase of 1-hexene isomerization reaction rates following sulfidization could be attributed to the electronegative sulfur species. Thiophene HDS appeared demand with the specific rates observed over 1.8 nm crystallites ca. 23 times greater than 9.8 nm crystallites. Thiophene HDS selectivities over Ru catalysts were found to depend on the amount of sulfur uptake and the manner in which sulfur was incorporated into the Ru crystallite. H/sub 2/ chemisorption studies, which showed higher levels of strongly bound hydrogen over RuS/sub 2/-like surfaces, provided one possible explanation. The results of thiophene-D/sub 2/ exchange experiments suggested that different thiophene adsorption mechanisms may be operative depending on presulfidization treatments: thiophene may adsorb via sulfur atoms following mild presulfidization, whereas thiophene may adsorb flatwise following extensive presulfidization.

• Research Organization: Aeronutronic, Newport Beach, CA (USA)
• OSTI ID: 5498790
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020400* -- Petroleum-- Processing
ALKENES
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL PREPARATION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMISORPTION
COHERENT SCATTERING
DESULFURIZATION
DEUTERIUM
DIFFRACTION
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY
FREE ENERGY
HETEROCYCLIC COMPOUNDS
HEXENES
HYDROCARBONS
HYDROGEN
HYDROGEN ISOTOPES
HYDROGENATION
ISOMERIZATION
ISOTOPES
ISOTOPIC EXCHANGE
KINETICS
LAYERS
LIGHT NUCLEI
METALS
NONMETALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXYGEN
PHOTOELECTRON SPECTROSCOPY
PHYSICAL PROPERTIES
PLATINUM METALS
REACTION KINETICS
RUTHENIUM
SCATTERING
SEPARATION PROCESSES
SORPTION
SPECTROSCOPY
STABLE ISOTOPES
SULFIDATION
SULFUR
SURFACE PROPERTIES
SYNTHESIS
THERMODYNAMIC PROPERTIES
THIOPHENE
TRANSITION ELEMENTS
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY