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  • Electronic Resource  (2)
  • KF2Mn(CO)12 as catalyst precursor  (1)
  • Mössbauer spectroscopy  (1)
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  • Electronic Resource  (2)
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  • 1
    Electronic Resource
    Electronic Resource
    Variable temperature13C MAS NMR of KFe2Mn(CO)12 in the solid state and as aCatalyst precursor on a carbon support (1989)
    Springer
    Catalysis letters 2 (1989), S. 413-422 
    Details
    ISSN: 1572-879X
    Keywords: Nuclear magnetic resonance for catalyst characterization ; KF2Mn(CO)12 as catalyst precursor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Variable temperature13C MAS NMR spectra are reported for13CO-enriched KFe2Mn(CO)12 as a solid and also as dispersed clusters on a carbon support. The spectrum of KFe2Mn(CO)12 at 300 K agrees with the proposed structure for this cluster and shows that the cluster is static. Two bridging carbonyl resonances are clearly resolved and, by comparison with13C MAS NMR spectra of Mn2(CO)10 and Fe2(CO)9, all terminal resonances for the cluster can be assigned. When the cluster is supported on carbon, two broad resonances are observed at room temperature which are assignable to KFe2Mn(CO)12 and a decomposition product, Mn2(CO)10. The carbonyl ligands in both supported clusters are completely averaged, and KFe2Mn(CO)12 on the carbon surface demonstrates fluxional behavior similar to that observed for the cluster in solution. For this fluxional process, activation energies of 0.6 kcal/mol and 0.5 kcal/mol are estimated for carbon-supported KFe2Mn(CO)12 and Mn2(CO)10, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00768184
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Olefin selective carbon-supported K-Fe-Mn CO hydrogenation catalysts: A kinetic, calorimetric, chemisorption, infrared and Mössbauer spectroscopic investigation (1990)
    Springer
    Catalysis letters 7 (1990), S. 219-240 
    Details
    ISSN: 1572-879X
    Keywords: Carbon supported Fe ; Fe-Mn ; K-Fe-Mn catalysts ; mixed metal carboxyl clusters ; chemisorption ; kinetic measurements ; calorimetric measurements ; infrared spectroscopy ; Mössbauer spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Carbon-supported Fe, Fe-Mn, and K-Fe-Mn catalysts derived from stoichiometric mixed-metal carbonyl clusters were pretreated at either 473 K or 673 K in hydrogen. Chemisorption and kinetic measurements were conducted following these pretreatments. The iron remained highly dispersed at all times except after high temperature reductions when potassium was present. The single promotion by either Mn or K increases the olefin/paraffin ratio, while the doubly promoted catalyst gave very high selectivities for light olefins. Isothermal, integral heats of adsorption of CO were determined at 300 K, and they increased from 15 kcal/mole for Fe3/C to nearly 17 kcal/mole for both the singly promoted Fe2Mn/C and KFe3/C catalysts to 21 kcal/mole for the doubly promoted KFe2Mn/C sample. A model of the decomposition of these carbonyl clusters is proposed based on calorimetric, Mössbauer effect spectroscopic and diffuse reflectance Fourier transform infrared spectroscopic studies. The state of the MnOx and K phases on the iron surface, as well as the Fe crystallite size, appears to play a dominant role in determining the catalytic behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00764505
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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