Abstract
Two phenomena have been studied: the action of {gamma} rays from radio-cobalt on the adsorption and catalytic properties of ZnO and NiO in. relationship with the heterogeneous oxidation of CO, and the homogeneous catalysis by OsO{sub 4} of the oxidation of various aqueous phase solutes by the same radiation. The prior irradiation of ZnO and of NiO does not modify their catalytic activity but generally increases the adsorption energy of -the gases CO and O{sub 2}. The influence of the radiations appears to be connected with the presence of traces of water on ZnO and of an excess of oxygen on NiO. Osmium tetroxide which is not degraded by irradiation in acid solution, accelerates the radiolytic oxidation of certain compounds (Te{sup IV}, Pt{sup 11}, As{sup 111}) in the presence of oxygen, as a result of its sensitizing effect on the oxidation by H{sub 2}O{sub 2}. In the case of phosphites on the other hand, OsO{sub 4} has a protecting action under certain conditions of acidity and may suppress entirely the chain reaction which characterizes the oxidation of this solute by{gamma} rays. A general mechanism is proposed for these phenomena. The rate constant for the OsO{sub 4} + HO{sub 2} reaction
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Dran, J C
[1]
- Commissariat a l'Energie Atomique, Saclay (France). Centre d'Etudes Nucleaires
Citation Formats
Dran, J C.
Study of catalytic phenomena in radiation chemistry; Etude des phenomenes catalytiques en chimie des radiations.
France: N. p.,
1965.
Web.
Dran, J C.
Study of catalytic phenomena in radiation chemistry; Etude des phenomenes catalytiques en chimie des radiations.
France.
Dran, J C.
1965.
"Study of catalytic phenomena in radiation chemistry; Etude des phenomenes catalytiques en chimie des radiations."
France.
@misc{etde_20702673,
title = {Study of catalytic phenomena in radiation chemistry; Etude des phenomenes catalytiques en chimie des radiations}
author = {Dran, J C}
abstractNote = {Two phenomena have been studied: the action of {gamma} rays from radio-cobalt on the adsorption and catalytic properties of ZnO and NiO in. relationship with the heterogeneous oxidation of CO, and the homogeneous catalysis by OsO{sub 4} of the oxidation of various aqueous phase solutes by the same radiation. The prior irradiation of ZnO and of NiO does not modify their catalytic activity but generally increases the adsorption energy of -the gases CO and O{sub 2}. The influence of the radiations appears to be connected with the presence of traces of water on ZnO and of an excess of oxygen on NiO. Osmium tetroxide which is not degraded by irradiation in acid solution, accelerates the radiolytic oxidation of certain compounds (Te{sup IV}, Pt{sup 11}, As{sup 111}) in the presence of oxygen, as a result of its sensitizing effect on the oxidation by H{sub 2}O{sub 2}. In the case of phosphites on the other hand, OsO{sub 4} has a protecting action under certain conditions of acidity and may suppress entirely the chain reaction which characterizes the oxidation of this solute by{gamma} rays. A general mechanism is proposed for these phenomena. The rate constant for the OsO{sub 4} + HO{sub 2} reaction is calculated to be 5.7 x 10{sup 5} l.mol{sup -1}. sec{sup -1}. (author) [French] Deux phenomenes ont ete etudies: l'action des rayons {gamma} du radio-cobalt sur les proprietes adsorptives et catalytiques de ZnO et NiO en relation avec l'oxydation heterogene de CO et la catalyse homogene par OsO{sub 4} de l'oxydation de divers solutes en phase aqueuse par ce meme rayonnement. L'irradiation prealable de ZnO et de NiO n'a pas modifie leur activite catalytique, mais a generalement accru l'energie d'adsorption des gaz CO et O{sub 2}. L'influence des radiations semble liee a la presence de traces d'eau sur ZnO et d'un exces d'oxygene sur NiO. Le tetroxyde d'osmium qui n'est pas altere par le rayonnement en solution acide, accelere l'oxydation radiolytique de certains composes. (Te{sup IV}, Pt{sup 11} et As{sup 111}) en la presence d'oxygene, par suite de son effet sensibilisateur sur l'oxydation par H{sub 2}O{sub 2}. Dans le cas des phosphites, par contre, OsO{sub 4} exerce une action protectrice dans certaines conditions d'acidite, en conduisant eventuellement a la suppression, de la reaction en chaine qui caracterisa l'oxydation de ce solute par les rayons {gamma}. Un mecanisme general de ces phenomenes est propose. La constante de vitesse de la reaction OsO{sub 4} + HO{sub 2} est evalue a 5,7.10{sup 5} I.mol{sup -1} s{sup -1}. (auteur)}
place = {France}
year = {1965}
month = {Jan}
}
title = {Study of catalytic phenomena in radiation chemistry; Etude des phenomenes catalytiques en chimie des radiations}
author = {Dran, J C}
abstractNote = {Two phenomena have been studied: the action of {gamma} rays from radio-cobalt on the adsorption and catalytic properties of ZnO and NiO in. relationship with the heterogeneous oxidation of CO, and the homogeneous catalysis by OsO{sub 4} of the oxidation of various aqueous phase solutes by the same radiation. The prior irradiation of ZnO and of NiO does not modify their catalytic activity but generally increases the adsorption energy of -the gases CO and O{sub 2}. The influence of the radiations appears to be connected with the presence of traces of water on ZnO and of an excess of oxygen on NiO. Osmium tetroxide which is not degraded by irradiation in acid solution, accelerates the radiolytic oxidation of certain compounds (Te{sup IV}, Pt{sup 11}, As{sup 111}) in the presence of oxygen, as a result of its sensitizing effect on the oxidation by H{sub 2}O{sub 2}. In the case of phosphites on the other hand, OsO{sub 4} has a protecting action under certain conditions of acidity and may suppress entirely the chain reaction which characterizes the oxidation of this solute by{gamma} rays. A general mechanism is proposed for these phenomena. The rate constant for the OsO{sub 4} + HO{sub 2} reaction is calculated to be 5.7 x 10{sup 5} l.mol{sup -1}. sec{sup -1}. (author) [French] Deux phenomenes ont ete etudies: l'action des rayons {gamma} du radio-cobalt sur les proprietes adsorptives et catalytiques de ZnO et NiO en relation avec l'oxydation heterogene de CO et la catalyse homogene par OsO{sub 4} de l'oxydation de divers solutes en phase aqueuse par ce meme rayonnement. L'irradiation prealable de ZnO et de NiO n'a pas modifie leur activite catalytique, mais a generalement accru l'energie d'adsorption des gaz CO et O{sub 2}. L'influence des radiations semble liee a la presence de traces d'eau sur ZnO et d'un exces d'oxygene sur NiO. Le tetroxyde d'osmium qui n'est pas altere par le rayonnement en solution acide, accelere l'oxydation radiolytique de certains composes. (Te{sup IV}, Pt{sup 11} et As{sup 111}) en la presence d'oxygene, par suite de son effet sensibilisateur sur l'oxydation par H{sub 2}O{sub 2}. Dans le cas des phosphites, par contre, OsO{sub 4} exerce une action protectrice dans certaines conditions d'acidite, en conduisant eventuellement a la suppression, de la reaction en chaine qui caracterisa l'oxydation de ce solute par les rayons {gamma}. Un mecanisme general de ces phenomenes est propose. La constante de vitesse de la reaction OsO{sub 4} + HO{sub 2} est evalue a 5,7.10{sup 5} I.mol{sup -1} s{sup -1}. (auteur)}
place = {France}
year = {1965}
month = {Jan}
}