Homogeneous catalysis of the water gas shift reaction by ruthenium and other metal carbonyls: studies in alkaline solutions
Homogeneous catalysis of the water gas shift reaction (H/sub 2/O + CO reversible H/sub 2/ + CO/sub 2/) has been demonstrated for a number of metal carbonyl complexes under alkaline conditions. Characterization of the catalysts based on ruthenium carbonyl in alkaline, aqueous ethoxyethanol solution demonstrates that the principal species present under the reaction conditions are the carbonyl hydride anions H/sub 3/Ru/sub 4/(CO)/sub 12//sup -/ and HRu/sub 3/CO)/sub 11//sup -/. (The room temperature synthesis of the latter ion by the reaction of Ru/sub 3/(CO)/sub 12/ in alcoholic KOH is described). The catalysis rate shows a first-order dependence on both the CO partial pressure and the total ruthenium concentration. Cyclic mechanisms proposed to explain these observations involve nucleophilic attack of water or of hydroxide on coordinated CO followed by decarboxylation to give hydridic species from which H/sub 2/ is eliminated in a CO-assisted, rate-limiting step. It is noted that catalysts prepared by adding both iron and ruthenium carbonyls to the same solution are more active than either the ruthenium-based or the iron-based catalysts alone. These mixed metal catalyst solutions are shown to contain mixed metal clusters, and it is proposed that the synergetic effect on catalytic activity may result from greater reactivity of the mixed metal clusters toward elimination of dihydrogen.
- Research Organization:
- Univ. of California, Santa Barbara
- OSTI ID:
- 5849134
- Journal Information:
- J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 101:20; ISSN JACSA
- Country of Publication:
- United States
- Language:
- English
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Water gas shift reaction: homogeneous catalysis by ruthenium and other metal carbonyls
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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
ALKALI METAL COMPOUNDS
ANIONS
AQUEOUS SOLUTIONS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CARBONYLS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
DATA
DATA FORMS
DISPERSIONS
EQUILIBRIUM
EXPERIMENTAL DATA
FLUIDS
FUEL GAS
FUELS
GAS FUELS
GASES
HYDRIDES
HYDROGEN COMPOUNDS
HYDROGEN PRODUCTION
INFORMATION
INTERMEDIATE BTU GAS
IONS
IRON COMPOUNDS
ISOLATED VALUES
KINETICS
MIXTURES
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PH VALUE
REACTION INTERMEDIATES
REACTION KINETICS
RUBIDIUM COMPOUNDS
SHIFT PROCESSES
SOLUTIONS
TRANSITION ELEMENT COMPOUNDS
WATER GAS
WATER GAS PROCESSES
YIELDS