Activation energies for the reactions O sup minus + H sub 2 and O sup minus + D sub 2 in aqueous solution

Journal Article · Thu Jan 24 04:00:00 EST 1991 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100155a047· OSTI ID:5940412

Hickel, B ^[1]; Sehested, K ^[2]

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1. CEA/Saclay, Gif sur Yvette (France)
2. Risoe National Lab., Roskilde (Denmark)

The reaction between molecular hydrogen and oxide radical ion in aqueous solution has been studied by pulse radiolysis in the temperature range 15-90{degree}C. At room temperature, k(O{sup {minus}} + H{sub 2}) = (1.1 {plus minus} 0.2) {times} 10{sup 8} mol{sup {minus}1} L s{sup {minus}1}, and the activation energy of the reaction is 13.8 {plus minus} 2 kJ/mol. The isotope effect on the reaction rate has been determined in H{sub 2}O. At 20{degree}C, k(O{sup {minus}} + D{sub 2}) = (2.5 {plus minus} 0.5) {times} 10{sup 7} mol{sup {minus}1} L s{sup {minus}1}, and the activation energy in the temperature range 20-80{degree}C is 20.8 {plus minus} 3 kJ/mol. Steady-state irradiation of H{sub 2}, D{sub 2}, and N{sub 2}O in alkaline solutions gives rise to a chain reaction. The chain is initiated and propagated by the hydrated electron and the oxide radical ion. The net result is an oxidation of H{sub 2} and D{sub 2} by N{sub 2}O with an important enrichment of the heavier isotope in the remaining hydrogen. The mechanism of the reaction O{sup {minus}} + H{sub 2} and the possibility that the primary step is not a hydrogen abstraction are discussed.

• OSTI ID: 5940412
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 95:2; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
ACTIVATION ENERGY
CHARGED PARTICLES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
DEUTERIUM
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
ENERGY
ENERGY RANGE
FERMIONS
HYDROGEN
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
IONS
ISOTOPE EFFECTS
ISOTOPES
KINETICS
LEPTONS
LIGHT NUCLEI
MEDIUM TEMPERATURE
MEV RANGE
MEV RANGE 01-10
NONMETALS
NUCLEI
ODD-ODD NUCLEI
OXYGEN COMPOUNDS
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIOLYSIS
REACTION KINETICS
SOLVATED ELECTRONS
STABLE ISOTOPES
WATER