Catalytic functionalities of supported sulfides. I. Effect of support and additives on the CoMo catalyst
C-S hydrogenolysis (HDS) of thiophene, hydrogenation (HYD) of 1-hexene, and hydrocracking (HCG) of 2,4,4-trimethyl-1-pentene, were used as separate model test reactions to differentiate and assess the catalytic functionalities of sulfided CoMo catalysts, and their dependence on the nature of the support and incorporation of additives. Rate constants and relative catalyst activities for these three reaction types were determined. HDS and HYD activities of CoMo supported on different types of Al/sub 2/O/sub 3/ were higher, while the HCG activity was lower compared with CoMo supported on SiO/sub 2/-Al/sub 2/O/sub 3/, SiO/sub 2/-MgO, or TiO/sub 2/. For SiO/sub 2/-Al/sub 2/O/sub 3/ supports both HDS and HYD activities decreased with increase in SiO/sub 2/ content from 10 to 75%, while HCG activity showed the opposite trend. Additives to a finished CoMo catalyst at 0.5% level caused variations in HDS and HCG activities, while HYD was essentially unaffected. HDS was promoted by NH/sub 4/HF/sub 2/ and NH/sub 4/Cl, but depressed by NaNO/sub 3/, Ca(NO/sub 3/)/sub 2/, and H/sub 3/BO/sub 3/. HCG was promoted by NH/sub 4/HF/sub 2/, NH/sub 4/Cl, and H/sub 3/BO/sub 3/. Additives at 5% level, prior to or after CoMo impregnation, showed a strong depressing effect on HDS and a lesser effect on HYD, while HCG was strongly promoted by NH/sub 4/HF/sub 2/, Ti isopropoxide, and H/sub 3/BO/sub 3/. The changes in catalytic functionalities are rationalized in terms of different interactions between CoMo phase, support, and additives. 3 tables, 1 figure.
- Research Organization:
- Univ. of Utah, Salt Lake City
- OSTI ID:
- 5292046
- Journal Information:
- J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 85:1; ISSN JCTLA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020300* -- Petroleum-- Drilling & Production
ADDITIVES
ALKENES
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL REACTIONS
COBALT
CRACKING
DECOMPOSITION
ELEMENTS
HETEROCYCLIC COMPOUNDS
HEXENES
HYDROCARBONS
HYDROCRACKING
HYDROGENATION
METALS
MOLYBDENUM
NONMETALS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PENTENES
PYROLYSIS
SULFUR
THERMOCHEMICAL PROCESSES
THIOPHENE
TRANSITION ELEMENTS