High value of kinetic isotopic effect during hydroxylation of cyclohexane catalyzed by iron porphyrins
The NaOCl-porphyrin iron chloride system (PorFeCl) that the authors recently discovered selectively oxidizes alkanes into alcohols at room temperature under interphase catalysis conditions. In this communication they submit data on the deuterisotopic effect k/sub H//k/sub D/ in the oxidation reaction of cyclohexane in this system, measured by the competitive reactions method. To explain the unusually high values of the isotopic effects (up to k/sub H//k/sub D/ = 21.9 for the tetramesitylporphyrin complex), they assume the contribution of tunneling during the transfer of the hydrogen atom from alkane to the oxygen atom coordinated to iron-porphyrin, since without the participation of tunneling, the k/sub H//k/sub D/ does not exceed the values of 6-8. If the tunneling is taken into account, the isotopic effect should probably decrease with increase in the electronegativity of the side substituents of the reacting porphyrin complex, which plays the role of an electrophile, since the energy barrier in the reaction with the C-H bond is thus lower. The data show that such a decrease in the value of k/sub H//k/sub D/ is indeed observed experimentally.
- Research Organization:
- Institute of Chemical Physics, Chernogolovka (USSR)
- OSTI ID:
- 5837119
- Journal Information:
- Kinet. Catal. (Engl. Transl.); (United States), Journal Name: Kinet. Catal. (Engl. Transl.); (United States) Vol. 29:4; ISSN KICAA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201 -- Chemical & Physicochemical Properties
400202* -- Isotope Effects
Isotope Exchange
& Isotope Separation
ALKALI METAL COMPOUNDS
ALKANES
CARBOXYLIC ACIDS
CATALYSIS
CATALYTIC EFFECTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
COMPLEXES
CYCLOALKANES
CYCLOHEXANE
DEUTERATION
DEUTERIUM
ELECTRONEGATIVITY
HALIDES
HALOGEN COMPOUNDS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
HYDROGEN ISOTOPES
HYDROXYLATION
IRON CHLORIDES
IRON COMPLEXES
IRON COMPOUNDS
ISOTOPE EFFECTS
ISOTOPES
KINETICS
LIGHT NUCLEI
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDATION
OXYCHLORIDES
OXYGEN COMPOUNDS
PORPHYRINS
REACTION KINETICS
SODIUM COMPOUNDS
STABLE ISOTOPES
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENT COMPOUNDS