Abstract
It is well known that the nuclear reactions Li{sup 6}(n, {alpha})T and He{sup 3}(n, p) T result in the formation of hot atoms of radioactive hydrogen. The characteristics of the chemical consequences of nuclear transformations are largely determined by the high chemical activity of such atoms. However, hydrogen atoms can play an essential role not only in nuclear chemistry but also in other branches of high-energy chemistry, such as radiolysis and photolysis. In the present research we attempted to make a comparative study of the behaviour of hot hydrogen atoms obtained in various ways: by the Li{sup 6} (n, {alpha})T reaction (recoil energy = 2.7 MeV); by radiolysis (E{approx} a few eV); by photolysis (E{approx} 1 - 1,5 eV; hot hydrogen is obtained from HI by photolysis at {lambda} = 2537A). In order to obtain tritium atoms, we used crystals and films of Li{sub 2}Co{sub 3}, Li{sup 6}F, Li{sup 6}OH, Li{sup 6}BO{sub 2} * 8H{sub 2} as targets. Gaseous ethylene (P = 5-10 atm) and its mixtures with ammonia, helium and inhibitors, were subjected to radiation. Radiation was carried out on an IRT-1000 reactor with a thermal neutron flux of 10{sup 11} - 10{sup 12} a/cm{sup 2} * s. Tritium-labelled
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Dzantiev, B. G.;
Shvedchikov, A. P.
[1]
- Institut Himicheskoj Fiziki AN SSSR, SSSR (Russian Federation)
Citation Formats
Dzantiev, B. G., and Shvedchikov, A. P.
Reactions of Hot Hydrogen Atoms with Ethylene. The Role of Excited Ethyl Radicals as Intermediate Products; Reactions des Atomes Chauds d'Hydrogene avec l'Ethylene. Le Role des Radicaux Ethyle Excites Comme Produits Intermediaires; Reaktsiya goryachikh atomov vodoroda s ehtilenom. Rol' vozbuzhdennykh ehtil'nykh radikalov kak promezhutochnykh produktov; Reacciones de Atomos Calientes de Hidrogeno con Etileno Papel de los Radicales Etilicos Excitados como Productos Intermedios.
IAEA: N. p.,
1965.
Web.
Dzantiev, B. G., & Shvedchikov, A. P.
Reactions of Hot Hydrogen Atoms with Ethylene. The Role of Excited Ethyl Radicals as Intermediate Products; Reactions des Atomes Chauds d'Hydrogene avec l'Ethylene. Le Role des Radicaux Ethyle Excites Comme Produits Intermediaires; Reaktsiya goryachikh atomov vodoroda s ehtilenom. Rol' vozbuzhdennykh ehtil'nykh radikalov kak promezhutochnykh produktov; Reacciones de Atomos Calientes de Hidrogeno con Etileno Papel de los Radicales Etilicos Excitados como Productos Intermedios.
IAEA.
Dzantiev, B. G., and Shvedchikov, A. P.
1965.
"Reactions of Hot Hydrogen Atoms with Ethylene. The Role of Excited Ethyl Radicals as Intermediate Products; Reactions des Atomes Chauds d'Hydrogene avec l'Ethylene. Le Role des Radicaux Ethyle Excites Comme Produits Intermediaires; Reaktsiya goryachikh atomov vodoroda s ehtilenom. Rol' vozbuzhdennykh ehtil'nykh radikalov kak promezhutochnykh produktov; Reacciones de Atomos Calientes de Hidrogeno con Etileno Papel de los Radicales Etilicos Excitados como Productos Intermedios."
IAEA.
@misc{etde_22141762,
title = {Reactions of Hot Hydrogen Atoms with Ethylene. The Role of Excited Ethyl Radicals as Intermediate Products; Reactions des Atomes Chauds d'Hydrogene avec l'Ethylene. Le Role des Radicaux Ethyle Excites Comme Produits Intermediaires; Reaktsiya goryachikh atomov vodoroda s ehtilenom. Rol' vozbuzhdennykh ehtil'nykh radikalov kak promezhutochnykh produktov; Reacciones de Atomos Calientes de Hidrogeno con Etileno Papel de los Radicales Etilicos Excitados como Productos Intermedios}
author = {Dzantiev, B. G., and Shvedchikov, A. P.}
abstractNote = {It is well known that the nuclear reactions Li{sup 6}(n, {alpha})T and He{sup 3}(n, p) T result in the formation of hot atoms of radioactive hydrogen. The characteristics of the chemical consequences of nuclear transformations are largely determined by the high chemical activity of such atoms. However, hydrogen atoms can play an essential role not only in nuclear chemistry but also in other branches of high-energy chemistry, such as radiolysis and photolysis. In the present research we attempted to make a comparative study of the behaviour of hot hydrogen atoms obtained in various ways: by the Li{sup 6} (n, {alpha})T reaction (recoil energy = 2.7 MeV); by radiolysis (E{approx} a few eV); by photolysis (E{approx} 1 - 1,5 eV; hot hydrogen is obtained from HI by photolysis at {lambda} = 2537A). In order to obtain tritium atoms, we used crystals and films of Li{sub 2}Co{sub 3}, Li{sup 6}F, Li{sup 6}OH, Li{sup 6}BO{sub 2} * 8H{sub 2} as targets. Gaseous ethylene (P = 5-10 atm) and its mixtures with ammonia, helium and inhibitors, were subjected to radiation. Radiation was carried out on an IRT-1000 reactor with a thermal neutron flux of 10{sup 11} - 10{sup 12} a/cm{sup 2} * s. Tritium-labelled compounds and products of radiation chemistry reactions were identified by gas chromatography involving the use of two monitoring units connected in series (a katharometer and a G-M flow counter). It is shown that the spectrum of labelled and unlabelled products in irradiated ethylene is very distinct. The main labelled products are C{sub 2}H{sub 2}, C{sub 2}H{sub 6}, C{sub 4}H{sub 10} and hydrocarbons > C{sub 4}; the H{sub 2} yield is small. The main unlabelled products are HT, C{sub 2}H{sub 3}T and C{sub 4}H{sub 9}T; the yield of C{sub 2}H{sub 5}T and especially of C{sub 2}HT is insignificant. The labelled-compound yields are dependent on the introduction of additives (ammonia, helium, iodine) into the ethylene, on the type of lithium-containing compound and on the structure of the target. Lowering the temperature from 50 Degree-Sign C to -78 Degree-Sign C has little effect on the distribution of labelled products; however, in the transition to heavy ethylene (-196 Degree-Sign C) a phase effect is observed; the HT and C{sub 4}H{sub 9}T yield decreases and the activity of the parent compound C{sub 2}H{sub 3}T increases, In the radiolysis of C{sub 2}H{sub 4} and its mixtures with ammonia the ratio C{sub 2}H{sub 6}/C{sub 4}H{sub 10} is equal to 1.0 {+-} 0.3, which does not agree with the standard scheme for disproportionation and recombination reactions of thermal ethylene radicals (C{sub 2}H{sub 6}/C{sub 4}H{sub 10} = 0.2 {+-} 0.1). On the basis of data on the effect of helium addition and temperature on C{sub 2}H{sub 6} and C{sub 4}H{sub 10}, yield in the radiolysis of C{sub 2}H{sub 4}, and in the photolysis of mixtures of C{sub 2}H{sub 4} and HI, we were able to get an idea of the formation of excited ethylene radicals of C2H* These are obtained as a result of the addition of hot hydrogen atoms (generated radiolytically or photolytically) to ethylene: H* + C{sub 2}H{sub 4} = C{sub 2}H*{sub 5}. It is shown that the C{sub 2}H*{sub 5} radical easily enters into the stripping reaction C{sub 2}H*{sub 5} + RH = C{sub 2}H{sub 6} + R, which accounts for the ''excess'' quantity of ethane formed in the radiolysis of ethylene [French] On sait qu'a la suite des reactions nucleaires Li{sup 6}(n, {alpha})T et He{sup 3}(n, p) T se forment des atomes chauds de tritium. La forte reactivite chimique de ces atomes determine a maints egards les particularites chimiques des effets dus aux transformations nucleaires. Or, les atomes chauds de tritium peuvent jouer un role important, non seulement en chimie nucleaire, mais aussi dans d'autres domaines de la chimie des hautes energies, notamment dans la radiolyse, la photolyse, etc. Dans le memoire, on essaie de comparer le comportement des atomes chauds de tritium obtenus par les moyens suivants: reaction Li{sup 6} (n, {alpha})T (E{sub sep} = 2,7 MeV); radiolyse (E Tilde-Operator plusieurs eV); photolyse (E Tilde-Operator 1 a 1,5 eV; le tritium se forme par photolyse a partir de H1 pour {lambda} = 2537A). Pour obtenir des atomes de tritium, on a utilise comme cibles des cristaux et des films de Li{sub 2}Co{sub 3}, Li{sup 6}F, Li{sup 6}OH, Li{sup 6}BO{sub 2} * 8H{sub 2}. On a irradie de l'ethylene en phase gazeuse (sous une pression p de 5 a 10 atm) et des melanges de ce corps avec l'ammoniac, l'helium et des inhibiteurs. L'irradiation a eu lieu a l'interieur d'un reacteur du type IRT-1000 dans un flux de neutrons thermiques de 10{sup 11} a 101{sup 12} n/cm{sup 2} * s. Les composes marques au tritium et les produits des reactions radiochimiques ont ete determines par voie de chromatographie gazeuse a l'aide de deux detecteurs montes en serie (un ' catharometre' et un compteur Geiger a balayage continu). Les auteurs montrent que dans l'ethylene irradie, la gamme des produits marques se distingue sensiblement de celle des produits non marques, Les principaux produits non marques sont; C{sub 2}H{sub 2}, C{sub 2}H{sub 6}, C{sub 4}H{sub 10} et des carbures a plus de quatre atomes d'hydrogene, le rendement en H2 etant faible. Les principaux produits marques sont; HT, C{sub 2}H{sub 3}T et C{sub 4}H{sub 9}T, le rendement en C{sub 2}H{sub 5}T et surtout en C{sub 2}HT etant negligeable. Le rendement en composes marques depend des substances ajoutees a l'ethylene (ammoniac, helium, iode), du compose contenant du lithium et de la structure de la cible. En ramenant la temperature de 50 Degree-Sign C to -78 Degree-Sign C, on ne modifie que faiblement la repartition des produits marques; cependant, lors du passage de l'ethylene a l'etat solide (-196 Degree-Sign C), on observe un effet de phase; la production de HT et C{sub 4}H{sub 9}T diminue, alors que l'activite de l'ethylene C{sub 2}H{sub 3}T augmente. Les auteurs montrent que lors de la radiolyse de C{sub 2}H{sub 4} et des melanges de ce carbure et d'ammoniac, le rapport C{sub 2}H{sub 6}/C{sub 4}H{sub 10} est egal a 1,0 {+-} 0,3, ce qui ne concorde pas avec le schema classique des reactions de dismutation et de recombinaison des radicaux ethyle thermiques (C{sub 2}H{sub 6}/C{sub 4}H{sub 10} = 0.2 {+-} 0.1). En se fondant sur les donnees relatives aux effets que les additions d'helium et la temperature exercent sur le rendement en C{sub 2}H{sub 6} et C{sub 4}H{sub 10} lors de la radiolyse de C{sub 2}H{sub 4} et de la photolyse des melanges C{sub 2}H{sub 4}-HI; les auteurs ont etabli une theorie expliquant l'apparition de radicaux d'ethyle excites C{sub 2}H*{sub 5} Ces derniers se forment lorsque des atomes chauds d'hydrogene (produits par la radiolyse ou la photolyse) se fixent sur l'ethylene suivant la formule: H* + C{sub 2}H{sub 4} = C{sub 2}H*{sub 5}. On montre que le radical C{sub 2}H*{sub 5} subit facilement la reaction C{sub 2}H*{sub 5} + RH = C{sub 2}H{sub 6} + R, ce qui explique pourquoi la radiolyse de l'ethylene donne lieu a la production d'un 'excedent' d'ethane. (author) [Spanish] Como resultado de las reacciones nucleares Li{sup 6}(n, {alpha})T y He{sup 3}(n, p)T se forman atomos calientes de tritio. La elevada actividad quimica de dichos atomos deteimina en gran parte las caracteristicas de los efectos quimicos de las transformaciones nucleares asociadas. Sin embargo, los atomos calientes de tritio pueden desempenar un papel esencial no solo en la quimica nuclear, sino tambien en otras esferas de la quimica de las altas energias: radiolisis, fotolisis, etc. En la presente memoria se compara el comportamiento de los atomos calientes de tritio, obtenidos de diversos modos: por la reaccion Li{sup 6} (n, {alpha})T (E = 2,7 MeV); por radiolisis (E Tilde-Operator algunos eV); por fotolisis (E Tilde-Operator 1 a 1,5 eV ; el hidrogeno caliente se obtiene a partir del HI por fotolisis, siendo {lambda} = 2 537 A). Como blancos para obtener atomos de tritio los autores utilizaron cristales y peliculas de Li{sub 2}Co{sub 3}, Li{sup 6}F, Li{sup 6}OH, Li{sup 6}BO{sub 2} * 8H{sub 2}. Irradiaron etileno gaseoso (P = 5 a 10 atm) y sus mezclas con amoniaco, helio e inhibidores. La irradiacion se efectuo en un reactor del tipo 1RT-1000, con un flujo de 10{sup 11} a 10{sup 12} neutrones termicos/cm{sup 2} * s. Los compuestos tritiados y los productos de las reacciones inducidas por radiaciones se determinaron por cromatografia de gases con ayuda de dos detectores montados en serie: un catarometro y un contador Geiger de corriente gaseosa. Los autores demuestran que el espectro de los productos marcados y sin marcar en el etileno irradiado presenta considerables diferencias. Los principales productos no marcados son el C{sub 2}H{sub 2}, C{sub 2}H{sub 6}, C{sub 4}H{sub 10} e hidrocarburos > C{sub 4}; el rendimiento de H{sub 2} es pequeno. Los principales productos marcados son el HT, C{sub 2}H{sub 3}T y C{sub 4}H{sub 9}T, el rendimiento de C{sub 2}H{sub 5}T y en especial de C{sub 2}HT es insignificante. Los rendimientos de los compuestos marcados dependen de la introduccion de aditivos (amoniaco, helio, yodo) en el etileno del tipo del compuesto que contiene litio y de la estructura del blanco. La disminucion de la temperatura desde 50 Degree-Sign C to -78 Degree-Sign C influye escasamente en la distribucion de los productos marcados; sin embargo, al pasar al etileno solido, a -196 Degree-Sign C, se observa un efecto de fases: disminuye el rendimiento de HT y de C{sub 4}H{sub 9}T y aumenta la actividad del compuesto original C{sub H3}T. Los autores demuestran que en la radiolisis del C{sub 2}H{sub 4} y de sus mezclas con amoniaco, la relacion C{sub 2}H{sub 6}/C{sub 4}H{sub 10} es igual a 1,0 {+-} 0,3, lo que no concuerda con el esquema clasico relativo a las reacciones de dismutacion y recombinacion termica de los radicales etileno (C{sub 2}H{sub 6}/C{sub 4}H{sub 10} = 0,2 {+-} 0,1). Basandose en los datos relativos a la influencia ejercida al anadir helio y al aumentar la temperatura sobre el rendimiento de C{sub 2}H{sub 6} y C{sub 4}H{sub 10} por radiolisis del C{sub 2}H{sub 4} y fotolisis de mezclas de C{sub 2}H{sub 4} -HI, los autores establecen una hipotesis sobre la formacion de radicales etilicos excitados (C{sub 2}H*{sub 5}). Estos ultimos se obtienen como resultado de la combinacion de atomos de hidrogeno calientes generados por radiolisis o por fotolisis, con el etileno: J* + C{sub 2}H{sub 4} = C{sub 2}H*{sub 5}. Demuestran que el radical C2Hf interviene facilmente en la reaccion C{sub 2}H*{sub 5} + RH = C{sub 2}H{sub 6} + R, que explica el 'exceso' de etano formado durante la radiolisis del etileno. (author) [Russian] Izvestno, chto v rezul'tate jadernyh reakcij Li{sup 6}(n, {alpha})T i He{sup 3}(n, p) T obrazujutsja gorjachie atomy radioaktivnogo vodoroda. Vysokaja himicheskaja aktivnost' takih atomov vo mnogom opredeljaet osobennosti himicheskih posledstvij jadernyh prevrashhenij. Odnako gorjachie atomy vodoroda mogut igrat' sushhestvennuju rol' ne tol'ko v jadernoj himii, no i v drugih oblastjah himii vysokih jenergij: pri radiolize, fotolize i t.d. V nastojashhej rabote sdelana popytka sopostavit' povedenie gorjachih atomov vodoroda, poluchaemyh razlichnym putem: pri reakcii i{sup 6}(n, {alpha})T (E{sub otd} = 2,7 Mjev), radioliticheski (E Tilde-Operator neskol'koojev), fotoliticheski (E Tilde-Operator 1 - 1,5 jev; gorjachij vodorod poluchaetsja iz HJ pri fotolize s {lambda}2537A). V kachestve mishenej dlja poluchenija atomov tritija ispol'zovalis' kristally i plenki Li{sub 2}Co{sub 3}, Li{sup 6}F, Li{sup 6}OH, Li{sup 6}BO{sub 2} * 8H{sub 2}. Oblucheniju podvergali gazoobraznyj jetilen (R = 5-10 atm.) i ego smesi s ammiakom, geliem i ingibitorami. Obluchenie provodilos' na rjoaktore tipa IRT-1000 pri potoke teplovyh nejtronov 10{sup 11} - 10{sup 12} n/cm{sup 2}sek. Mechennye po tritiju soedinenija i produkty radiacionno-himicheskih reakcij opredeljali gazohromatograficheski s pomoshh'ju dvuh posledovatel'no soedinennyh.datchikov (katarometr) i protochnyj schetchik Gejgera). Pokazano, chto spektr mechenyh i nemechenyh produktov v obluchaemom jetilene znachitel'no otlichaetsja. Osnovnymi nemechenymi produktami javljajutsja C{sub 2}H{sub 2}, C{sub 2}H{sub 6}, C{sub 4}H{sub 10} i uglevodorody >C{sub 4}; vyhod H{sub 2} mal. Osnovnymi nemechenymi produktami javljajutsja HT, C{sub 2}H{sub 3}T i. C{sub 4}H{sub 9}T, vyhod C{sub 2}H5T i osobenno C{sub 2}HT neznachitelen. Vyhody mechenyh soedinenij zavisjat ot vvedenija dobavok v jetilen (ammiak, gelij, jod), vida litijsoderzhashhego soedinenija, struktury misheni. Ponizhenie temperatury s 50 do -78 Degree-Sign malo vlijaet na raspredelenie mechenyh produktov, odnako, pri perehode k tverdomu jetilenu (-196 Degree-Sign C) nabljudaetsja fazovyj jeffekt: umen'shaetsja vyhod HT i C{sub 4}H{sub 9}T i uvelichivaetsja aktivnost' materinskogo soedinenija C{sub 2}H{sub 3}T. Pokazano, chto pri radiolize C{sub 9}H{sub 4} i ego smesej s ammiakom otnoshenie C{sub 2}H{sub 6}/C{sub 4}H{sub 10} ravno 1,0 {+-} 0,3, chto ne soglasuetsja s kanonicheskoj shemoj dlja reakcij disproporcionirovanija i rekombinacii teplovyh jetil'nyh radikalov (C{sub 2}H{sub 6}/C{sub 4}H{sub 10} = 0,2 {+-} 0,1). Na osnovanii dannyh po vlijaniju dobavok gelija i temperatury na vyhod C{sub 2}H{sub 6} i C{sub 4} Nju pri radiolize C{sub 2}H{sub 4} i pri fotolize smesej C{sub 2}H{sub 4} -HJ sformulirovano predstavlenie ob obrazovanii vozbuzhdennyh jetil'nyh radikalov C{sub 2}H{sub 5}*. Poslednie poluchajutsja za schet prisoedinenija gorjachih atomov vodoroda (generiruemyh radioliticheski ili fotoliticheski) k jetilenu: H* + C{sub 2}H{sub 4} = C{sub 2}H{sub 5}*. Pokazano, chto C{sub 2}H{sub 5}*-radikal legko vstupaet v reakciju otryva C{sub 2}H*{sub 5} + RH = C{sub 2}H{sub 6} + R, chto ob'jasnjaet ''izbytochnoe'' kolichestvo jetana, obrazujushhegosja pri radiolize jetilena. (author)}
place = {IAEA}
year = {1965}
month = {Apr}
}
title = {Reactions of Hot Hydrogen Atoms with Ethylene. The Role of Excited Ethyl Radicals as Intermediate Products; Reactions des Atomes Chauds d'Hydrogene avec l'Ethylene. Le Role des Radicaux Ethyle Excites Comme Produits Intermediaires; Reaktsiya goryachikh atomov vodoroda s ehtilenom. Rol' vozbuzhdennykh ehtil'nykh radikalov kak promezhutochnykh produktov; Reacciones de Atomos Calientes de Hidrogeno con Etileno Papel de los Radicales Etilicos Excitados como Productos Intermedios}
author = {Dzantiev, B. G., and Shvedchikov, A. P.}
abstractNote = {It is well known that the nuclear reactions Li{sup 6}(n, {alpha})T and He{sup 3}(n, p) T result in the formation of hot atoms of radioactive hydrogen. The characteristics of the chemical consequences of nuclear transformations are largely determined by the high chemical activity of such atoms. However, hydrogen atoms can play an essential role not only in nuclear chemistry but also in other branches of high-energy chemistry, such as radiolysis and photolysis. In the present research we attempted to make a comparative study of the behaviour of hot hydrogen atoms obtained in various ways: by the Li{sup 6} (n, {alpha})T reaction (recoil energy = 2.7 MeV); by radiolysis (E{approx} a few eV); by photolysis (E{approx} 1 - 1,5 eV; hot hydrogen is obtained from HI by photolysis at {lambda} = 2537A). In order to obtain tritium atoms, we used crystals and films of Li{sub 2}Co{sub 3}, Li{sup 6}F, Li{sup 6}OH, Li{sup 6}BO{sub 2} * 8H{sub 2} as targets. Gaseous ethylene (P = 5-10 atm) and its mixtures with ammonia, helium and inhibitors, were subjected to radiation. Radiation was carried out on an IRT-1000 reactor with a thermal neutron flux of 10{sup 11} - 10{sup 12} a/cm{sup 2} * s. Tritium-labelled compounds and products of radiation chemistry reactions were identified by gas chromatography involving the use of two monitoring units connected in series (a katharometer and a G-M flow counter). It is shown that the spectrum of labelled and unlabelled products in irradiated ethylene is very distinct. The main labelled products are C{sub 2}H{sub 2}, C{sub 2}H{sub 6}, C{sub 4}H{sub 10} and hydrocarbons > C{sub 4}; the H{sub 2} yield is small. The main unlabelled products are HT, C{sub 2}H{sub 3}T and C{sub 4}H{sub 9}T; the yield of C{sub 2}H{sub 5}T and especially of C{sub 2}HT is insignificant. The labelled-compound yields are dependent on the introduction of additives (ammonia, helium, iodine) into the ethylene, on the type of lithium-containing compound and on the structure of the target. Lowering the temperature from 50 Degree-Sign C to -78 Degree-Sign C has little effect on the distribution of labelled products; however, in the transition to heavy ethylene (-196 Degree-Sign C) a phase effect is observed; the HT and C{sub 4}H{sub 9}T yield decreases and the activity of the parent compound C{sub 2}H{sub 3}T increases, In the radiolysis of C{sub 2}H{sub 4} and its mixtures with ammonia the ratio C{sub 2}H{sub 6}/C{sub 4}H{sub 10} is equal to 1.0 {+-} 0.3, which does not agree with the standard scheme for disproportionation and recombination reactions of thermal ethylene radicals (C{sub 2}H{sub 6}/C{sub 4}H{sub 10} = 0.2 {+-} 0.1). On the basis of data on the effect of helium addition and temperature on C{sub 2}H{sub 6} and C{sub 4}H{sub 10}, yield in the radiolysis of C{sub 2}H{sub 4}, and in the photolysis of mixtures of C{sub 2}H{sub 4} and HI, we were able to get an idea of the formation of excited ethylene radicals of C2H* These are obtained as a result of the addition of hot hydrogen atoms (generated radiolytically or photolytically) to ethylene: H* + C{sub 2}H{sub 4} = C{sub 2}H*{sub 5}. It is shown that the C{sub 2}H*{sub 5} radical easily enters into the stripping reaction C{sub 2}H*{sub 5} + RH = C{sub 2}H{sub 6} + R, which accounts for the ''excess'' quantity of ethane formed in the radiolysis of ethylene [French] On sait qu'a la suite des reactions nucleaires Li{sup 6}(n, {alpha})T et He{sup 3}(n, p) T se forment des atomes chauds de tritium. La forte reactivite chimique de ces atomes determine a maints egards les particularites chimiques des effets dus aux transformations nucleaires. Or, les atomes chauds de tritium peuvent jouer un role important, non seulement en chimie nucleaire, mais aussi dans d'autres domaines de la chimie des hautes energies, notamment dans la radiolyse, la photolyse, etc. Dans le memoire, on essaie de comparer le comportement des atomes chauds de tritium obtenus par les moyens suivants: reaction Li{sup 6} (n, {alpha})T (E{sub sep} = 2,7 MeV); radiolyse (E Tilde-Operator plusieurs eV); photolyse (E Tilde-Operator 1 a 1,5 eV; le tritium se forme par photolyse a partir de H1 pour {lambda} = 2537A). Pour obtenir des atomes de tritium, on a utilise comme cibles des cristaux et des films de Li{sub 2}Co{sub 3}, Li{sup 6}F, Li{sup 6}OH, Li{sup 6}BO{sub 2} * 8H{sub 2}. On a irradie de l'ethylene en phase gazeuse (sous une pression p de 5 a 10 atm) et des melanges de ce corps avec l'ammoniac, l'helium et des inhibiteurs. L'irradiation a eu lieu a l'interieur d'un reacteur du type IRT-1000 dans un flux de neutrons thermiques de 10{sup 11} a 101{sup 12} n/cm{sup 2} * s. Les composes marques au tritium et les produits des reactions radiochimiques ont ete determines par voie de chromatographie gazeuse a l'aide de deux detecteurs montes en serie (un ' catharometre' et un compteur Geiger a balayage continu). Les auteurs montrent que dans l'ethylene irradie, la gamme des produits marques se distingue sensiblement de celle des produits non marques, Les principaux produits non marques sont; C{sub 2}H{sub 2}, C{sub 2}H{sub 6}, C{sub 4}H{sub 10} et des carbures a plus de quatre atomes d'hydrogene, le rendement en H2 etant faible. Les principaux produits marques sont; HT, C{sub 2}H{sub 3}T et C{sub 4}H{sub 9}T, le rendement en C{sub 2}H{sub 5}T et surtout en C{sub 2}HT etant negligeable. Le rendement en composes marques depend des substances ajoutees a l'ethylene (ammoniac, helium, iode), du compose contenant du lithium et de la structure de la cible. En ramenant la temperature de 50 Degree-Sign C to -78 Degree-Sign C, on ne modifie que faiblement la repartition des produits marques; cependant, lors du passage de l'ethylene a l'etat solide (-196 Degree-Sign C), on observe un effet de phase; la production de HT et C{sub 4}H{sub 9}T diminue, alors que l'activite de l'ethylene C{sub 2}H{sub 3}T augmente. Les auteurs montrent que lors de la radiolyse de C{sub 2}H{sub 4} et des melanges de ce carbure et d'ammoniac, le rapport C{sub 2}H{sub 6}/C{sub 4}H{sub 10} est egal a 1,0 {+-} 0,3, ce qui ne concorde pas avec le schema classique des reactions de dismutation et de recombinaison des radicaux ethyle thermiques (C{sub 2}H{sub 6}/C{sub 4}H{sub 10} = 0.2 {+-} 0.1). En se fondant sur les donnees relatives aux effets que les additions d'helium et la temperature exercent sur le rendement en C{sub 2}H{sub 6} et C{sub 4}H{sub 10} lors de la radiolyse de C{sub 2}H{sub 4} et de la photolyse des melanges C{sub 2}H{sub 4}-HI; les auteurs ont etabli une theorie expliquant l'apparition de radicaux d'ethyle excites C{sub 2}H*{sub 5} Ces derniers se forment lorsque des atomes chauds d'hydrogene (produits par la radiolyse ou la photolyse) se fixent sur l'ethylene suivant la formule: H* + C{sub 2}H{sub 4} = C{sub 2}H*{sub 5}. On montre que le radical C{sub 2}H*{sub 5} subit facilement la reaction C{sub 2}H*{sub 5} + RH = C{sub 2}H{sub 6} + R, ce qui explique pourquoi la radiolyse de l'ethylene donne lieu a la production d'un 'excedent' d'ethane. (author) [Spanish] Como resultado de las reacciones nucleares Li{sup 6}(n, {alpha})T y He{sup 3}(n, p)T se forman atomos calientes de tritio. La elevada actividad quimica de dichos atomos deteimina en gran parte las caracteristicas de los efectos quimicos de las transformaciones nucleares asociadas. Sin embargo, los atomos calientes de tritio pueden desempenar un papel esencial no solo en la quimica nuclear, sino tambien en otras esferas de la quimica de las altas energias: radiolisis, fotolisis, etc. En la presente memoria se compara el comportamiento de los atomos calientes de tritio, obtenidos de diversos modos: por la reaccion Li{sup 6} (n, {alpha})T (E = 2,7 MeV); por radiolisis (E Tilde-Operator algunos eV); por fotolisis (E Tilde-Operator 1 a 1,5 eV ; el hidrogeno caliente se obtiene a partir del HI por fotolisis, siendo {lambda} = 2 537 A). Como blancos para obtener atomos de tritio los autores utilizaron cristales y peliculas de Li{sub 2}Co{sub 3}, Li{sup 6}F, Li{sup 6}OH, Li{sup 6}BO{sub 2} * 8H{sub 2}. Irradiaron etileno gaseoso (P = 5 a 10 atm) y sus mezclas con amoniaco, helio e inhibidores. La irradiacion se efectuo en un reactor del tipo 1RT-1000, con un flujo de 10{sup 11} a 10{sup 12} neutrones termicos/cm{sup 2} * s. Los compuestos tritiados y los productos de las reacciones inducidas por radiaciones se determinaron por cromatografia de gases con ayuda de dos detectores montados en serie: un catarometro y un contador Geiger de corriente gaseosa. Los autores demuestran que el espectro de los productos marcados y sin marcar en el etileno irradiado presenta considerables diferencias. Los principales productos no marcados son el C{sub 2}H{sub 2}, C{sub 2}H{sub 6}, C{sub 4}H{sub 10} e hidrocarburos > C{sub 4}; el rendimiento de H{sub 2} es pequeno. Los principales productos marcados son el HT, C{sub 2}H{sub 3}T y C{sub 4}H{sub 9}T, el rendimiento de C{sub 2}H{sub 5}T y en especial de C{sub 2}HT es insignificante. Los rendimientos de los compuestos marcados dependen de la introduccion de aditivos (amoniaco, helio, yodo) en el etileno del tipo del compuesto que contiene litio y de la estructura del blanco. La disminucion de la temperatura desde 50 Degree-Sign C to -78 Degree-Sign C influye escasamente en la distribucion de los productos marcados; sin embargo, al pasar al etileno solido, a -196 Degree-Sign C, se observa un efecto de fases: disminuye el rendimiento de HT y de C{sub 4}H{sub 9}T y aumenta la actividad del compuesto original C{sub H3}T. Los autores demuestran que en la radiolisis del C{sub 2}H{sub 4} y de sus mezclas con amoniaco, la relacion C{sub 2}H{sub 6}/C{sub 4}H{sub 10} es igual a 1,0 {+-} 0,3, lo que no concuerda con el esquema clasico relativo a las reacciones de dismutacion y recombinacion termica de los radicales etileno (C{sub 2}H{sub 6}/C{sub 4}H{sub 10} = 0,2 {+-} 0,1). Basandose en los datos relativos a la influencia ejercida al anadir helio y al aumentar la temperatura sobre el rendimiento de C{sub 2}H{sub 6} y C{sub 4}H{sub 10} por radiolisis del C{sub 2}H{sub 4} y fotolisis de mezclas de C{sub 2}H{sub 4} -HI, los autores establecen una hipotesis sobre la formacion de radicales etilicos excitados (C{sub 2}H*{sub 5}). Estos ultimos se obtienen como resultado de la combinacion de atomos de hidrogeno calientes generados por radiolisis o por fotolisis, con el etileno: J* + C{sub 2}H{sub 4} = C{sub 2}H*{sub 5}. Demuestran que el radical C2Hf interviene facilmente en la reaccion C{sub 2}H*{sub 5} + RH = C{sub 2}H{sub 6} + R, que explica el 'exceso' de etano formado durante la radiolisis del etileno. (author) [Russian] Izvestno, chto v rezul'tate jadernyh reakcij Li{sup 6}(n, {alpha})T i He{sup 3}(n, p) T obrazujutsja gorjachie atomy radioaktivnogo vodoroda. Vysokaja himicheskaja aktivnost' takih atomov vo mnogom opredeljaet osobennosti himicheskih posledstvij jadernyh prevrashhenij. Odnako gorjachie atomy vodoroda mogut igrat' sushhestvennuju rol' ne tol'ko v jadernoj himii, no i v drugih oblastjah himii vysokih jenergij: pri radiolize, fotolize i t.d. V nastojashhej rabote sdelana popytka sopostavit' povedenie gorjachih atomov vodoroda, poluchaemyh razlichnym putem: pri reakcii i{sup 6}(n, {alpha})T (E{sub otd} = 2,7 Mjev), radioliticheski (E Tilde-Operator neskol'koojev), fotoliticheski (E Tilde-Operator 1 - 1,5 jev; gorjachij vodorod poluchaetsja iz HJ pri fotolize s {lambda}2537A). V kachestve mishenej dlja poluchenija atomov tritija ispol'zovalis' kristally i plenki Li{sub 2}Co{sub 3}, Li{sup 6}F, Li{sup 6}OH, Li{sup 6}BO{sub 2} * 8H{sub 2}. Oblucheniju podvergali gazoobraznyj jetilen (R = 5-10 atm.) i ego smesi s ammiakom, geliem i ingibitorami. Obluchenie provodilos' na rjoaktore tipa IRT-1000 pri potoke teplovyh nejtronov 10{sup 11} - 10{sup 12} n/cm{sup 2}sek. Mechennye po tritiju soedinenija i produkty radiacionno-himicheskih reakcij opredeljali gazohromatograficheski s pomoshh'ju dvuh posledovatel'no soedinennyh.datchikov (katarometr) i protochnyj schetchik Gejgera). Pokazano, chto spektr mechenyh i nemechenyh produktov v obluchaemom jetilene znachitel'no otlichaetsja. Osnovnymi nemechenymi produktami javljajutsja C{sub 2}H{sub 2}, C{sub 2}H{sub 6}, C{sub 4}H{sub 10} i uglevodorody >C{sub 4}; vyhod H{sub 2} mal. Osnovnymi nemechenymi produktami javljajutsja HT, C{sub 2}H{sub 3}T i. C{sub 4}H{sub 9}T, vyhod C{sub 2}H5T i osobenno C{sub 2}HT neznachitelen. Vyhody mechenyh soedinenij zavisjat ot vvedenija dobavok v jetilen (ammiak, gelij, jod), vida litijsoderzhashhego soedinenija, struktury misheni. Ponizhenie temperatury s 50 do -78 Degree-Sign malo vlijaet na raspredelenie mechenyh produktov, odnako, pri perehode k tverdomu jetilenu (-196 Degree-Sign C) nabljudaetsja fazovyj jeffekt: umen'shaetsja vyhod HT i C{sub 4}H{sub 9}T i uvelichivaetsja aktivnost' materinskogo soedinenija C{sub 2}H{sub 3}T. Pokazano, chto pri radiolize C{sub 9}H{sub 4} i ego smesej s ammiakom otnoshenie C{sub 2}H{sub 6}/C{sub 4}H{sub 10} ravno 1,0 {+-} 0,3, chto ne soglasuetsja s kanonicheskoj shemoj dlja reakcij disproporcionirovanija i rekombinacii teplovyh jetil'nyh radikalov (C{sub 2}H{sub 6}/C{sub 4}H{sub 10} = 0,2 {+-} 0,1). Na osnovanii dannyh po vlijaniju dobavok gelija i temperatury na vyhod C{sub 2}H{sub 6} i C{sub 4} Nju pri radiolize C{sub 2}H{sub 4} i pri fotolize smesej C{sub 2}H{sub 4} -HJ sformulirovano predstavlenie ob obrazovanii vozbuzhdennyh jetil'nyh radikalov C{sub 2}H{sub 5}*. Poslednie poluchajutsja za schet prisoedinenija gorjachih atomov vodoroda (generiruemyh radioliticheski ili fotoliticheski) k jetilenu: H* + C{sub 2}H{sub 4} = C{sub 2}H{sub 5}*. Pokazano, chto C{sub 2}H{sub 5}*-radikal legko vstupaet v reakciju otryva C{sub 2}H*{sub 5} + RH = C{sub 2}H{sub 6} + R, chto ob'jasnjaet ''izbytochnoe'' kolichestvo jetana, obrazujushhegosja pri radiolize jetilena. (author)}
place = {IAEA}
year = {1965}
month = {Apr}
}