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Effects of Incorporated Radioactivity and External Radiation on Heterogeneous Catalysis; Effets de la radioactivite incorporee et des rayonnements externes sur la catalyse heterogene; Vliyanie vvedennoj radioaktivnosti i vneshnego oblucheniya na geterogennyj kataliz; Efectos de la radiactividad incorporada y de la irradiacion externa sobre la catalisis heterogenea

Conference:

Abstract

The vapour phase dehydration of cyclohexanol on magnesium sulphate and magnesium sulphatesodium sulphate catalysts and the dehydrogenation of methylcyclohexane to toluene on promoted chromiaalumina catalysts were studied in flow systems. The effects of incorporating radioisotopes into the catalysts and of pre-irradiation with cobalt-60 gamma rays were investigated. Magnesium sulphate and magnesium sulphate-sodium sulphate catalysts containing up to 45.5 mc (S{sup 35})/g were less active than non-radioactive catalysts of similar composition when compared on a unit surface area basis. The reduction in catalytic activity persisted even after the radioactivity had substantially decayed. Further, no change in catalytic activity was observed upon irradiation with X-rays while the reaction was in progress. From these results it is concluded that the emission of beta particles from the catalyst during its use has no effect. Reports of an enhancement of catalytic activity may be attributed to the fact that,for a given set of preparation conditions, the radioactive catalysts have larger surface areas than their non-radioactive counterparts, and that this was not taken into account. Pre-irradiation with cobalt-60 gamma rays to 10{sup 11} erg/g had no effect on the catalysts' activity. In contrast, pre-irradiation of the chromia-alumina catalysts with cobalt-60 gamma rays to a dose of  More>>
Authors:
Krohn, N. A.; Wymer, R. G. [1] 
  1. Oak Ridge National Laboratory, Oak Ridge and University of Tennessee, Knoxville, Tennessee (United States)
Publication Date:
Nov 15, 1963
Product Type:
Conference
Resource Relation:
Conference: Conference on the Application of Large Radiation Sources in Industry, Salzburg (Austria), 27-31 May 1963; Other Information: 6 figs., 3 tabs., 7 refs.; Related Information: In: Industrial Uses of Large Radiation Sources. Proceedings of a Conference on the Application of Large Radiation Sources in Industry. Vol. II| 344 p.
Subject:
36 MATERIALS SCIENCE; ACTIVATION ENERGY; CATALYSTS; COBALT 60; CYCLOHEXANOL; DEHYDROGENATION; GAMMA RADIATION; HETEROGENEOUS CATALYSIS; IRRADIATION; MAGNESIUM; PROMETHIUM 147; SULFATES; SURFACE AREA; X RADIATION
OSTI ID:
22108170
Research Organizations:
International Atomic Energy Agency, Vienna (Austria)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13R0358065981
Submitting Site:
INIS
Size:
page(s) 25-39
Announcement Date:
Jun 27, 2013

Conference:

Citation Formats

Krohn, N. A., and Wymer, R. G. Effects of Incorporated Radioactivity and External Radiation on Heterogeneous Catalysis; Effets de la radioactivite incorporee et des rayonnements externes sur la catalyse heterogene; Vliyanie vvedennoj radioaktivnosti i vneshnego oblucheniya na geterogennyj kataliz; Efectos de la radiactividad incorporada y de la irradiacion externa sobre la catalisis heterogenea. IAEA: N. p., 1963. Web.
Krohn, N. A., & Wymer, R. G. Effects of Incorporated Radioactivity and External Radiation on Heterogeneous Catalysis; Effets de la radioactivite incorporee et des rayonnements externes sur la catalyse heterogene; Vliyanie vvedennoj radioaktivnosti i vneshnego oblucheniya na geterogennyj kataliz; Efectos de la radiactividad incorporada y de la irradiacion externa sobre la catalisis heterogenea. IAEA.
Krohn, N. A., and Wymer, R. G. 1963. "Effects of Incorporated Radioactivity and External Radiation on Heterogeneous Catalysis; Effets de la radioactivite incorporee et des rayonnements externes sur la catalyse heterogene; Vliyanie vvedennoj radioaktivnosti i vneshnego oblucheniya na geterogennyj kataliz; Efectos de la radiactividad incorporada y de la irradiacion externa sobre la catalisis heterogenea." IAEA.
@misc{etde_22108170,
title = {Effects of Incorporated Radioactivity and External Radiation on Heterogeneous Catalysis; Effets de la radioactivite incorporee et des rayonnements externes sur la catalyse heterogene; Vliyanie vvedennoj radioaktivnosti i vneshnego oblucheniya na geterogennyj kataliz; Efectos de la radiactividad incorporada y de la irradiacion externa sobre la catalisis heterogenea}
author = {Krohn, N. A., and Wymer, R. G.}
abstractNote = {The vapour phase dehydration of cyclohexanol on magnesium sulphate and magnesium sulphatesodium sulphate catalysts and the dehydrogenation of methylcyclohexane to toluene on promoted chromiaalumina catalysts were studied in flow systems. The effects of incorporating radioisotopes into the catalysts and of pre-irradiation with cobalt-60 gamma rays were investigated. Magnesium sulphate and magnesium sulphate-sodium sulphate catalysts containing up to 45.5 mc (S{sup 35})/g were less active than non-radioactive catalysts of similar composition when compared on a unit surface area basis. The reduction in catalytic activity persisted even after the radioactivity had substantially decayed. Further, no change in catalytic activity was observed upon irradiation with X-rays while the reaction was in progress. From these results it is concluded that the emission of beta particles from the catalyst during its use has no effect. Reports of an enhancement of catalytic activity may be attributed to the fact that,for a given set of preparation conditions, the radioactive catalysts have larger surface areas than their non-radioactive counterparts, and that this was not taken into account. Pre-irradiation with cobalt-60 gamma rays to 10{sup 11} erg/g had no effect on the catalysts' activity. In contrast, pre-irradiation of the chromia-alumina catalysts with cobalt-60 gamma rays to a dose of 4.2 x 10{sup 11} erg/g enhanced the catalytic activity by about 34% at 485{sup o}C, but incorporation of up to 148 mc (Pm{sup 147})/g of catalyst had little or no effect. No substantial effect of radiation on surface area or on apparent activation energy was observed in this case. (author) [French] Les auteurs ont etudie dans des circuits la deshydratation du cyclohexanol en phase vapeur en presence de catalyseurs au sulfate de magnesium et au sulfate double de magnesium et de sodium, et la transformation du methylcyclohexane toluene par deshydrogenation en presence de catalyseurs au Cr{sub 2}O{sub 3} - Al{sub 2}O{sub 3} active. Ils ont fait des recherches sur les effets de l'incorporation de radioisotopes dans les catalyseurs et d'une exposition prealable aux rayons gamma du cobalt-60. Les catalyseurs au sulfate de magnesium et au sulfate double de magnesium et de sodium contenant jusqu'a 45,5 mc de {sup 35}S par gramme etaient moins actifs que les catalyseurs non radioactifs de composition analogue si on les comparait par unite de surface. La reduction de l'activite catalytique persistait meme apres qu'une desintegration importante se fut produite. En outre, on n'a pas observe de changements de l'activite catalytique sous exposition a des rayons X au cours de la reaction. On en conclut que l'emission de particules beta par le catalyseur au cours de son emploi est sans effet. Les resultats faisant etat d'une augmentation de l'activite catalytique peuvent etre attribues au fait que pour des conditions donnees de preparation, les catalyseurs radioactifs ont une plus grande surface que leur correspondants non radioactiis et qu'on n'avait pas tenu compte de ce fait. L'exposition prealable de ces catalyseurs aux rayons gamma du cobalt-60 a raison de 10{sup 11} erg/g a ete sans effet sur l'activite du catalyseur. Par contre, la meme exposition prealable des catalyseurs au Cr{sub 2}O{sub 3} - Al{sub 2}O{sub 3} aux rayons gamma du cobalt-60 a raison de 4,2 x 10{sup 11} erg/g a augmente l'activite catalytique d'environ 34% a 485{sup o}C, mais l'incorporation d'une quantite de {sup 147}Pm atteignant 148 mc/g de catalyseur est restee pratiquement sans effet. On n'a pas observe dans ce cas d'effet significatif des rayonnements sur la surface active ou sur l'energie d'activation apparente. (author) [Spanish] Los autores estudian la deshidratacion del ciclohexanol en fase vapor en presencia de catalizadores de sulfato magnesico y d e sulfato magnesico-sulfato sodico, asi como la transformacion del metilciclohexano en tolueno por deshidrogenacion sobre catalizadores de oxido de cromo-alumina activados, en sistemas de circulacion. Examinan tambien los efectos de la incorporacion de radioisotopos en los catalizadores y de su preirradiacion con los rayos gamma emitidos por una fuente de cobalto-60. Los catalizadores de sulfato magnesico y de sulfato magnesico-sulfato sodico, con un contenido de hasta 45, 5 mc de {sup 35}S, se revelaron menos activos por unidad de superficie que los catalizadores no radiactivos de composicion analoga. La merma de actividad catalitica subsistio incluso despues de haber disminuido considerablemente la radiactividad. Ademas, no se observo cambio alguno en l a actividad catalitica despues de una exposicion a rayos X en el curso de la reaccion. Estos resultados sugieren a los autores que la emision de particulas beta por el catalizador durante su empleo no ejerce ningun efecto. Las informaciones relativas a un incremento de esa actividad catalitica podrian atribuirse al hecho de que, para un conjunto dado de condiciones de preparacion, los catalizadores radiactivos ofrecen una superficie mayor que sus equivalentes no radiactivos, circunstancia esta que no fue tenida en cuenta. La preirradiacion con los rayos gamma del cobalto-60 en dosis de hasta 10{sup 11} erg/g no influyo en absoluto sobre la actividad de los catalizadores. Por el contrario, la preirradiacion gamma del cobalto-60 de catalizadores de oxido de cromo-alumina con dosis de 4,2 x 10{sup 11} erg/g incremento esa actividad en un 34% aproximadamente a 485{sup o}C, pero la incorporacion de hasta 148 me de {sup 147}Pm por gramo de catalizador tuvo escaso o ningun efecto. En este caso, las radiaciones no ejercieron un efecto notable sobre el area superficial o sobre la energia de attivacion aparente. (author) [Russian] Na tsirkulyatsionno-staticheskoj ustanovke issledovany parofaehnaya degidratatsiya tsiklogeksanola s primeneniem sul'fatmagnievogo i sul'fatmagnievogo - sul'fatnatrivogo katalizatorov i degidrogenizatsiya metiltsiklogeksana v toluol na aktivirovannykh alyumokhromovykh katalizatorakh. Izucheny ehffekty vvedeniya v katalizator radioaktivnykh izotopov i predvaritel'nogo gamma-oblucheniya ot istochnika Co''6''0. Sud'fatmagnievyj katalizator i katalizator smeshannogo tipa sul'fat magniya + sul'fat natriya, soderzhashchie do 45,5 mkkyuri (S''3''5)/r, pri raschete na edinitsu poverkhnosti menee aktivny, chem katalizatory togo zhe sostava, no ne soderzhashchie radioaktivnykh izotopov. Oslablenie kataliticheskoj aktivnosti sokhranyalos' dazhe posle togo, kak radioaktivnost' sushchestvenno pala, dalee, pri obluchenii rentgenovskimi luchami, kotoroe provodilos' v protsesse reaktsii, nikakikh izmenenij v kataliticheskoj aktivnosti ne nablyudalos'. Na osnovanii ehtikh dannykh sdelan vyvod, chto ehmissiya beta-chastits iz katalizatora v protsesse ego ispol'zovaniya ne okazyvaet nikakogo vliyaniya. Soobshcheniya ob usilenii kataliticheskoj aktivnosti sleduet otnesti za schet togo, chto pri prigotovlenii katalizatorov u tekh iz nikh, kotorye soderzhali radioaktivnye izotopy, vozmozhno poluchalas' bol'shaya ploshchad' poverkh- nosti, chem u tekh, kotorye ne soderzhali radioaktivnykh izotopov. Ehto obstoyatel'stvo ne bylo prinyato vo vnimanie. Predvaritel'noe gamma-obluchenie ot istochnika Co''6''0 dozoj 10''1''1 erg/g ne okazalo vliyaniya na kataliticheskuyu aktivnost'. S drugoj storony, predvaritel'noe obluchenie gamma-luchami ot istochnika Co{sup 60} alyumokhromovykh katalizatorov dozoj 4,2 x 10{sup 11} erg/g usililo kataliticheskuyu aktivnost' pochti na 34%, pri 485{sup o}C. V to zhe vremya vvedenie v katalizator do 148 mkkyuri (Pm{sup 147} )/g katalizatora ne okazyvalo pochti nikakogo vozdejstviya. V ehtom sluchae ne nablyudalos' skol'ko-nibud' zametnogo vliyaniya izlucheniya na ploshchad' poverkhnosti ili na kazhushchuyusya ehnergiyu aktivatsii. (author)}
place = {IAEA}
year = {1963}
month = {Nov}
}