Mechanistic study on the alcohol synthesis over molybdenum catalysts: Addition of probe molecules to CO-H sub 2
- Univ. of Tokyo, Hongo (Japan)
The addition of probe molecules, such as ethylene, propylene, methanol, ethanol, and acetaldehyde, to CO-H{sub 2} feed was studied over the KCl-promoted and the unpromoted Mo/SiO{sub 2} catalyst under synthetic conditions, in order to clarify the reaction paths for the formation of hydrocarbons and alcohols. The results of olefin addition study suggest that the alcohol formation from CO-H{sub 2} proceeds by a mechanism including steps identical with those in the hydrocarbonylation of olefins and that KCl suppresses the simple hydrogenation of olefins. Both of the Mo catalysts demonstrate a poor catalytic activity for the homologation of methanol to ethanol. Alcohol homologation seems to be only a minor process in the formation of C{sub 2}{sup +} alcohols. No significant activity of Mo catalysts for incorporation of acetaldehyde into C{sub 3} oxygenated compounds may exclude the intermediacy of aldehydes for the chain growth of alcohols. Hydrogenation of acetaldehyde to ethanol is the fast and predominant reaction, in agreement with the fact that alcohols compose more 90% of the organic oxygenates produced from CO-H{sub 2}. Aldol condensation is apparently unimportant for the chain growth. The contribution of alcohol dehydration to hydrocarbon formation may be insignificant over the KCl-promoted catalyst with K/Mo = 0.4. Consequently, a mechanism including CO insertion into the alkyl-metal bond is proposed for the main reaction path for the higher alcohol formation from CO-H{sub 2}. The role of K is supposed to slow the hydrogenation of surface alkyl species to form alkanes as well as to increase the active sites for alcohol formation by retarding the reduction of Mo.
- OSTI ID:
- 6912846
- Journal Information:
- Journal of Catalysis; (USA), Journal Name: Journal of Catalysis; (USA) Vol. 115:2; ISSN 0021-9517; ISSN JCTLA
- Country of Publication:
- United States
- Language:
- English
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ACETALDEHYDE
ADDITIVES
ALCOHOLS
ALDEHYDES
ALKALI METAL COMPOUNDS
ALKENES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYST SUPPORTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
ELEMENTS
ETHANOL
ETHYLENE
FLUIDS
FUEL ADDITIVES
GASES
HALIDES
HALOGEN COMPOUNDS
HYDROCARBONS
HYDROGENATION
HYDROXY COMPOUNDS
KINETICS
METALS
METHANOL
MINERALS
MOLYBDENUM
ORGANIC COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
POTASSIUM CHLORIDES
POTASSIUM COMPOUNDS
PROMOTERS
PROPYLENE
REACTION INTERMEDIATES
REACTION KINETICS
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SYNTHESIS
SYNTHESIS GAS
TRANSITION ELEMENTS