Gas-phase studies of alkane oxidation by transition-metal oxides. Selective oxidation by CrO/sup +/
The gas-phase reactions of CrO/sup +/ with alkanes have been studied by using ion beam reactive scattering techniques. CrO/sup +/ undergoes facile reactions with alkanes larger than methane. CrO/sup +/ selectively oxidizes ethane to form ethanol. In addition to the possibility of alcohol formation, reactions with larger alkanes are more complex, yielding products in which dehydrogenation and loss of alkenes and alkanes occur. In reactions with cyclic alkanes, cyclopropane and cyclobutane yield products characteristic of C-C bond cleavage. In contrast, reactions with cyclopentane and cyclohexane mainly involve dehydrogenation and elimination of H/sub 2/O. A series of hydrogen abstraction reactions are examined to determine the bond dissociation energy D/sup 0/ (CrO/sup +/-H) = 89 +/- 5 kcal mol/sup -1/. This bond energy has implications for the reaction mechanisms of CrO/sup +/ with alkanes, leading to the suggestion of a multicenter reaction intermediate, in which alkyl C-H bonds add across the Cr/sup +/-O bond as an initial step. This is supported by an examination of the reactions of Cr/sup +/ with alcohols.
- Research Organization:
- California Institute of Technology, Pasadena
- OSTI ID:
- 6953141
- Journal Information:
- J. Am. Chem. Soc.; (United States), Vol. 108:24
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BUTANE
OXIDATION
CYCLOALKANES
CYCLOHEXANE
ETHANE
ETHANOL
CHEMICAL PREPARATION
PENTANE
PROPANE
BINDING ENERGY
CHROMIUM OXIDES
DEHYDROGENATION
EXPERIMENTAL DATA
GASES
ION-MOLECULE COLLISIONS
ORGANOMETALLIC COMPOUNDS
REACTION INTERMEDIATES
THERMODYNAMICS
ALCOHOLS
ALKANES
CHALCOGENIDES
CHEMICAL REACTIONS
CHROMIUM COMPOUNDS
COLLISIONS
DATA
ENERGY
FLUIDS
HYDROCARBONS
HYDROXY COMPOUNDS
INFORMATION
ION COLLISIONS
MOLECULE COLLISIONS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties