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Effects of Temperature and Pressure on Hot-Atom Reactions in Bromoethane; Effets de la Temperature et de la Pression sur les Reactions des Atomes Chauds dans le Bromoethane; Vliyanie temperatury i davleniya na reaktsii goryachikh atomov v bromehtane; Efectos de la Temperatura y de la Presion en las Reacciones de Atomos Calientes en el Bromoetano

Conference:

Abstract

A study has been made of the yields of compounds containing Br{sup 80m} produced by irradiation of bromethane- bromine mixtures with 14 MeV neutrons at 18 Degree-Sign C, -80 Degree-Sign C and -115 Degree-Sign C, and at atmospheric pressure, and also at 18 Degree-Sign C at pressures up to 10{sup 4} atm. In addition to compounds previously reported in this system, small quantities of bromoethene, 1:2 dibromoethene, mono-and dibromopropanes, and mono-, di-, tri- and tetra-bromo- butanes have been found. There is also indirect evidence for the production of bromobutenes. The diffusion-dependent reactions are complex, and can be explained by assuming that pyrolysis of the liquid occurs in the vicinity of the hot atom to give bromoethyl radicals and ethylene. Addition of radicals to the latter then accounts for the formation of bromides containing more than two carbon atoms and for their diffusion-dependent yields. Reduction in temperature or increase in pressure generally causes an increase in yield attributable to a decreased rate of diffusion. The effect is most marked upon the yield of 1:2 dibromoethane, which is largely produced by the diffusive reaction of bromoethyl radicals and which increases fourfold by the application of 10{sup 4} atm because of the suppression  More>>
Authors:
Cole, A. J.; Mia, M. D.; Miller, G. E.; Shaw, P. F.D. [1] 
  1. Nuclear Physics Laboratory, Oxford University, Oxford (United Kingdom)
Publication Date:
Apr 15, 1965
Product Type:
Conference
Report Number:
IAEA-SM-57/93
Resource Relation:
Conference: Symposium on Chemical Effects Associated with Nuclear Reactions and Radioactive Transformations, Vienna (Austria), 7-11 Dec 1964; Other Information: 24 refs., 8 figs., 4 tabs.; Related Information: In: Chemical Effects of Nuclear Transformations Vol. I. Proceedings of the Symposium on Chemical Effects Associated with Nuclear Reactions and Radioactive Transformations| 457 p.
Subject:
38 RADIATION CHEMISTRY, RADIOCHEMISTRY AND NUCLEAR CHEMISTRY; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ATMOSPHERIC PRESSURE; BROMIDES; BROMINE; BROMINE 80; BUTANE; CARBON; CONCENTRATION RATIO; DIFFUSION; DISSOCIATION; ETHYLENE; HOT ATOM CHEMISTRY; HYDROGEN; MEV RANGE; NEUTRON REACTIONS; PRESSURE DEPENDENCE; PYROLYSIS; RADIATION EFFECTS; RADICALS; TEMPERATURE DEPENDENCE; YIELDS
OSTI ID:
22141779
Research Organizations:
International Atomic Energy Agency, Vienna (Austria); Joint Commission on Applied Radioactivity of the International Council of Scientific Unions, Paris (France)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13M3309096380
Submitting Site:
INIS
Size:
page(s) 351-370
Announcement Date:
Oct 24, 2013

Conference:

Citation Formats

Cole, A. J., Mia, M. D., Miller, G. E., and Shaw, P. F.D. Effects of Temperature and Pressure on Hot-Atom Reactions in Bromoethane; Effets de la Temperature et de la Pression sur les Reactions des Atomes Chauds dans le Bromoethane; Vliyanie temperatury i davleniya na reaktsii goryachikh atomov v bromehtane; Efectos de la Temperatura y de la Presion en las Reacciones de Atomos Calientes en el Bromoetano. IAEA: N. p., 1965. Web.
Cole, A. J., Mia, M. D., Miller, G. E., & Shaw, P. F.D. Effects of Temperature and Pressure on Hot-Atom Reactions in Bromoethane; Effets de la Temperature et de la Pression sur les Reactions des Atomes Chauds dans le Bromoethane; Vliyanie temperatury i davleniya na reaktsii goryachikh atomov v bromehtane; Efectos de la Temperatura y de la Presion en las Reacciones de Atomos Calientes en el Bromoetano. IAEA.
Cole, A. J., Mia, M. D., Miller, G. E., and Shaw, P. F.D. 1965. "Effects of Temperature and Pressure on Hot-Atom Reactions in Bromoethane; Effets de la Temperature et de la Pression sur les Reactions des Atomes Chauds dans le Bromoethane; Vliyanie temperatury i davleniya na reaktsii goryachikh atomov v bromehtane; Efectos de la Temperatura y de la Presion en las Reacciones de Atomos Calientes en el Bromoetano." IAEA.
@misc{etde_22141779,
title = {Effects of Temperature and Pressure on Hot-Atom Reactions in Bromoethane; Effets de la Temperature et de la Pression sur les Reactions des Atomes Chauds dans le Bromoethane; Vliyanie temperatury i davleniya na reaktsii goryachikh atomov v bromehtane; Efectos de la Temperatura y de la Presion en las Reacciones de Atomos Calientes en el Bromoetano}
author = {Cole, A. J., Mia, M. D., Miller, G. E., and Shaw, P. F.D.}
abstractNote = {A study has been made of the yields of compounds containing Br{sup 80m} produced by irradiation of bromethane- bromine mixtures with 14 MeV neutrons at 18 Degree-Sign C, -80 Degree-Sign C and -115 Degree-Sign C, and at atmospheric pressure, and also at 18 Degree-Sign C at pressures up to 10{sup 4} atm. In addition to compounds previously reported in this system, small quantities of bromoethene, 1:2 dibromoethene, mono-and dibromopropanes, and mono-, di-, tri- and tetra-bromo- butanes have been found. There is also indirect evidence for the production of bromobutenes. The diffusion-dependent reactions are complex, and can be explained by assuming that pyrolysis of the liquid occurs in the vicinity of the hot atom to give bromoethyl radicals and ethylene. Addition of radicals to the latter then accounts for the formation of bromides containing more than two carbon atoms and for their diffusion-dependent yields. Reduction in temperature or increase in pressure generally causes an increase in yield attributable to a decreased rate of diffusion. The effect is most marked upon the yield of 1:2 dibromoethane, which is largely produced by the diffusive reaction of bromoethyl radicals and which increases fourfold by the application of 10{sup 4} atm because of the suppression of the dissociation CH{sub 2}-CH{sub 2}Br Rightwards-Arrow-Over-Leftwards-Arrow CH{sub 2} = CH{sub 2} + Br under the influence of the ''hot-spike''. By contrast, dissociation of the radical (CH{sub 3} - CHBr) into bromoethene and a hydrogen atom is energetically forbidden, and the yield of 1: 1 dibromoethane is roughly independent of pressure. The variation with temperature and pressure of the yield of bromoethane at large bromine concentrations is close to that predicted previously. (author) [French] Les auteurs ont etudie les rendements en composes contenant {sup 80m}Br produits par exposition de melanges de bromoethane-brome a des neutrons de 14 MeV aux temperatures de 18 Degree-Sign , -80 Degree-Sign et -115 Degree-Sign C et a la pression atmospherique, ainsi qu'a la temperature de 18 Degree-Sign C et a des pressions allant jusqu'a 10{sup 4} atm. En plus des composes deja signales, ils ont trouve de faibles quantites de bromoethylene, de dibromo- 1,2-ethylene, de mono-et dibromopropanes et de mono-, di-, tri-et tetrabromobutanes; il existe en outre des indices indirects de la formation de bromobutenes. Les reactions qui dependent de la diffusion sont complexes-, on peut les expliquer en admettant qu'une pyrolyse du liquide se produit dans le voisinage de l'atome chaud et donne des radicaux bromoethyle et de l'ethylene. C'est alors a l'addition de radicaux a l'ethylene que sont dus a la fois la formation de bromures contenant plus de deux atomes de carbone et les rendements en ces bromures, qui dependent de la diffusion. D'une maniere generale, une reduction de la temperature ou un accroissement de la pression entraine une augmentation du rendement imputable a une diminution de la vitesse de diffusion. L'effet est le plus marque sur le rendement en dibromo-1, 2-ethanef qui se produit surtout par la reaction de diffusion des radicaux bromoethyle et qui est quadruple par l'application de 10{sup 4} atm du fait de la suppression de la dissociation CH{sub 2}-CH{sub 2}Br Rightwards-Arrow-Over-Leftwards-Arrow CH{sub 2} = CH{sub 2} + Br En revanche, la dissociation du radical (CH{sub 3} -CHBr) en bromoethylene et hydrogene (CH{sub 2} = CHBr + H) est impossible, et le rendement en dibromo-1,1-ethane est a peu pres independant de la pression. La variation, en fonction de la temperature et de la pression, du rendement en bromoethane pour de fortes concentrations de brome est voisine de celle qui avait ete prevue precedemment par l'un des auteurs. (author) [Spanish] Se ha estudiado el rendimiento de los compuestos que contienen {sup 80m}Br, producidos por irradiacion de mezclas de bromoetano y bromo con neutrones de 14 MeV a 18 Degree-Sign C, -80 Degree-Sign C y -115 Degree-Sign C y a la presion atmosferica, asi como a 18 Degree-Sign C y presiones de hasta 10{sup 4} atm. Ademas de los compuestos ya conocidos en este sistema, se han hallado pequeflas cantidades de bromoetano, 1,2-dibromoetano, mono y dibromo- propanos y mono, di, tri y tetra bromobutanos; tambien hay pruebas indirectas de produccion debromobutenos. Las reacciones dependientes de la difusion son complejas, y se pueden explicar suponiendo que en las proximidades del atomo caliente se produce una pirolisis del liquido por la que se forman radicales bromo- etilo y etileno. La adicion de radicales a este ultimo determina la formacion de bromuros que contienen mas de dos atomos de carbono, asi como sus rendimientos dependientes de la difusion. La disminucion de la temperatura o el aumento de la presion se traduce por lo general en un incremento del rendimiento atribuible a una menor velocidad de difusion. El. efecto es mas acusado en el rendimiento de 1, 2-dibromoetano producido principalmente por la reaccion difusiva de radicales bromoetilo, que se cuadruplica al aplicar una presion de 10{sup 4} atm debido a la supresion de la disociacion CH{sub 2}-CH{sub 2}Br Rightwards-Arrow-Over-Leftwards-Arrow CH{sub 2} = CH{sub 2} + Br bajo la influencia de la ''punta termica''. En cambio, la disociacion del radical (CH{sub 3} -CHBr) en bromoetano y un atomo de hidrogeno no es energeticamente viable, y el rendimiento de 1,1-dibromoetano es casi independiente de la presion. La variacion del rendimiento de bromoetano para grandes concentraciones de bromo en funcion de la temperatura y de la presion se aproxima al valor que se habia previsto. (author) [Russian] Izuchalis' vyhody soedinenij, soderzhashhih Br{sup 80m} kotoryj byl poluchen oblucheniem smesej bromjetan-bromina nejtronami 14 Mjev pri temperaturah 18 Degree-Sign C, -80 Degree-Sign C i -115 Degree-Sign C pri atmosfernom davlenii, a takzhe pri 18 Degree-Sign C i davlenijah do 10{sup 4} atmosfer. Pomimo soedinenij jetoj sistemy,o kotoryh soobshhalos' ranee, byli najdeny nebol'shie kolichestva bromjetena, 1:2 dibromjetena, mono- i dibrompropanov i moho-, di-, tri- i tetra- brombutanov; est' takzhe kosvennoe dokazatel'stvo proizvodstva brombutenov. Diffuzionno-zavisimye reakcii javljajutsja kompleksnymi i mogut byt' ob{sup j}asneny, predpolozhiv, chto piroliz zhidkosti proishodit v okrestnosti gorjachego atoma s polucheniem brom- jetilovyh radikalov i jetilena. Dobavlenie radikalov k poslednemu otvechaet za obrazovanie bromidov, soderzhashhih bolee chem 2 atoma ugleroda i za ih diffuzionno-zavisimye vyhody. Ponizhenie temperatury ili uvelichenie davlenija obychno vyzyvaet uvelichenie vyhoda, svjazannogo s umen'shennoj skorost'ju diffuzii. Jeffekt osobenno znachitelen dlja vyhoda 1:2 dibromojetana, kotoryj proizvoditsja glavnym obrazom reakciej diffuzii bromjetilovyh radikalov i kotoryj uvelichivaetsja v chetyre raza pri primenenii 10{sup 4} atmosfer blagodarja podavleniju dissociacii CH{sub 2}-CH{sub 2}Br Rightwards-Arrow-Over-Leftwards-Arrow CH{sub 2} = CH{sub 2} + Br pod davleniem ''gorjachego pika''. Naprotiv, dissociacija radikala (CH{sub 3} - CHBr) na brom- jeten i atom vodoroda javljaetsja jenergeticheski zapreshhennoj, i vyhod 1:1 dibromjetana grubo nezavisim ot davlenija. Izmenenie vyhoda bromjetana v zavisimosti ot temperatury i davlenija pri bol'shih koncentracijah bromina blizko k tomu, chto predskazyvalos' ranee. (author)}
place = {IAEA}
year = {1965}
month = {Apr}
}