STRUCTURE AND CATALYTIC PROPERTIES OF MOLYBDENA-CHROMIA DEHYDROGENATION CATALYSTS
It is known that molybdenum (VI) and chromium oxides supported on Al/sub 2/O/sub 3/ have high activities in hydrocarbon dehydrogenation reactions. The authors investigate the MoO/sub 3/-Cr/sub 2/O/sub 3/ system in more detail in order to ascertain the nature of the active component and to invetsigate the influence of the component ratio on the yield of the desired product. The catalyst test samples were prepared by dissolving the calculated quantities of ammonium paramolybdate and dichromate, grade sp. in distilled water, subsequently mixing the two solutions and boiling off the solvent. A study of the phase composition of molybdena-chromia catalysts for dehydrogenation, in the interval of Cr/sub 2/O/sub 3/ concentrations from 0 to 100% by weight, has shown that with Cr/sub 2/O/sub 3/ concentrations from 10% to 80% by weight, the compound Cr/sub 2/(MoO/sub 4/)/sub 3/ is present, built up structurally from MoO/sub 4/ tetrahedra and CrO/sub 6/ octahedra. With contents of Cr/sub 2/O/sub 3/ below 10% or above 80%, only the respective phases of MoO/sub 3/ and alpha-Cr/sub 2/O/sub 3/ are observed. The changes in the x-ray diffraction patterns and the IR spectra of MoO/sub 3/ specimens calcined at temperatures above 550degrees because of processes of severe sintering of the molybdenum (VI) oxide in this region of temperatures. It has been shown that the high activity of molybdena-chromia catalysts in the reaction of isoamylene dehydrogenation to isoprene is related to the formation of chromium molybdate.
- Research Organization:
- Kuzbass Polytechnic Institute
- OSTI ID:
- 7202809
- Journal Information:
- J. Appl. Chem. USSR (Engl. Transl.); (United States), Journal Name: J. Appl. Chem. USSR (Engl. Transl.); (United States) Vol. 58:2,PT.2; ISSN JAPUA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
ACTIVATION ENERGY
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AMMONIUM COMPOUNDS
AQUEOUS SOLUTIONS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHROMATES
CHROMIUM COMPOUNDS
CHROMIUM OXIDES
COMPARATIVE EVALUATIONS
DEHYDROGENATION
DIENES
DISPERSIONS
ENERGY
HIGH TEMPERATURE
HYDROCARBONS
ISOPRENE
MIXTURES
MOLYBDATES
MOLYBDENUM COMPOUNDS
MOLYBDENUM OXIDES
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
POLYENES
QUANTITY RATIO
REFRACTORY METAL COMPOUNDS
SOLUTIONS
TRANSITION ELEMENT COMPOUNDS