Investigation of the Reactions of the Recoil Carbon-14 Atoms in Some Heterogeneous Mixtures

Barakat, M. F.; Zahran, A. H.

doi:10.1524/ract.1970.13.3.152

Cited by 3 publications

(2 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Quartz ampoules, half filled with the organic materials to be irradiated, were attached to a high vacuum line and were sealed under vacuum as described in a previous publication (13). lrradiations were carried o u t in the 2 MW research reactor of the Atomic Energy Authority (Egypt).…”

Section: Preparation Of Targets and Irradiationmentioning

confidence: 99%

Investigation of the Polymers Formed in Reactor Irradiated Aniline and Pyridine

Barakat¹,

Abdel-Kerim²

1973

Can. J. Chem.

View full text Add to dashboard Cite

In reactor irradiated aniline or pyridine most of the radiocarbon generated by the 14N(n,p)14C reaction was found preferentially localized in a polymer-like material, brown in color, frequently lustrous and constituting 15-30% of the initial amount of the irradiated material. This stimulated us t o try to obtain an idea about the chemical groupings existing in these highly radioactive materials a n d thereafter to deduce their possible formation pathways.By comparing the i.r. spectra of these polymers with those of the corresponding pure compounds it was possible to detect some changes in the spectra on polymerization and consequently it was possible t o identify some basic structural groups existing. Based on these findings some polymerization reaction mechanisms have been suggested. In general, polymer formation was assumed to take place through the formation of polymerization centers produced by the rupture of the aromatic rings to give highly unsaturated fragments and radicals. These are capable of adding different radicals and fragments formed in the irradiated material by radiolysis or by the action of energetic recoil atoms. Cross linking between individual polymer chains was observed. The preferential localisation of 14C in the polymer fraction could be attributed to the great capacity of the recoil atoms to form reactive secondary species such as 14CH3', 14CH2", or 1 4 C H which participate in polymer formation.L'aniline ou la pyridine irradiee dans un rkacteur oh la majorit6 des radiocarbones produits provient de la reaction L4N(n,p)'4C, se retrouve priferentiellement, comme il a kt6 trouve, sous forme d'un produit du type polymere, de couleur brunltre souvent reluisant et comportant 15-30% de la quantitt initiale du materiel irradie. Cette constatation nous a alors amene a rechercher les diffkrents groupements chimiques present dans ces produits hautement radioactifs et par suite i en deduire les differentes voies possibles de formation.En comparant les spectres i.r. de ces polymeres avec ceux des esptces pures correspondantes, il fut possible de deceler certains changements dans les spectres a la suite de la polymerisation e t par suite il fut possible d'identifier quelques groupes structuraux presents. En se basant sur ces donnees, quelques mecanismes de reactions de polymerisation furent entrevues. En general, la formation des polymeres semble se produire i la suite de la formation de centres de polymerisation dkcoulant d e la rupture des cycles aromatiques pour donner des fragments hautement insatures ainsi que des radicaux. Ceux-ci sont capables d'additionner differents radicaux et diffkrents fragments formks dans le matkriel irradie par radiolyse ou ti la suite de I'action d'atomes trts energetiques. On a aussi observe la formation de ponts entre differentes chaines polymeriques individuelles. On a attribue la localisation preftrentielle du 14C dans la fraction contenant le polymtre a la grande facilitk des atomes energetiques i former des esptces reactives secondaires telles 14CH3., l4CH2-ou " ...

show abstract

Section: Preparation Of Targets and Irradiationmentioning

confidence: 99%

Investigation of the Polymers Formed in Reactor Irradiated Aniline and Pyridine

Barakat¹,

Abdel-Kerim²

1973

Can. J. Chem.

View full text Add to dashboard Cite

show abstract

“…Two acetanilide samples were placed in quartz ampoules which were sealed under vacuum in the usual way [30]. Irradiations were carried out for 48 h in the 2 MW research reactor of the AEA, using thermal neutron fluxes 0.7 χ IO 13 n/cm 2 sec (sample I) and 0.3 X 10 13 n/cm 3 sec (sample II).…”

Section: Preparation Of Targets and Irradiationmentioning

confidence: 99%

Chemical Effects Associated with the Thermal Neutron Irradiation of Solid Acetanilide (Antifibrin)

Barakat¹,

Zahran

1972

Radiochimica Acta

Self Cite

View full text Add to dashboard Cite

Reactions of recoil carbon-14 atoms have been studied in neutron irradiated acetanilide system. The reaction mechanisms in solid systems are discussed with reference to those occurring in simple gaseous and liquid systems. The "random fragmentation" hypothesis seems to oifer an adequate explanation. Most of the products identified were the result of different recombination processes between fragments formed by the severe fragmentation of the irradiated material. 14 Clabelled acetanilide was obtained with the highest radiochemical yield. The radiochemical yields of the simple synthetic products were higher than those of more complicated products. Labelled methyl derivatives were not detected. The infra red spectrum of the polymer separated showed a marked similarity, in absorption bands, to the spectrum of pure acetanilide except for the possible appearance of -CH 2 -groups in the polymer spectrum. ZusammenfassungReaktionen von KohlenstofF-14-Rückstoßatomen sind in einem mit Neutronen bestrahlten Acetanilidsystem untersucht worden. Die Reaktionsmechanismen in Festkörpersystemen werden in bezug auf die in einfachen gasförmigen und flüssigen Systemen auftretenden Mechanismen behandelt. Die Hypothese der "statistischen Zertrümmerung" scheint eine ausreichende Erklärung zu bieten. Die meisten identifizierten Produkte stammten aus verschiedenen Rekombinationsprozessen zwischen Bruchstücken, die durch die starke Zertrümmerung des bestrahlten Materials entstanden waren. Mit 14 C markiertes Acetanilid wurde mit der höchsten radiochemischen Ausbeute erhalten. Die radiochemischen Ausbeuten der einfachen synthetischen Produkte waren höher als die der komplizierteren Produkte. Markierte Methylderivate wurden nicht festgestellt. Das Infrarotspektrum des abgetrennten Polymers deutete auf eine bemerkenswerte Ähnlichkeit in den Absorptionsbanden mit den im Spektrum von reinem Acetanilid nachgewiesenen, mit der Ausnahme des möglichen Auftretens von -CH 2 -Gruppen im Polymerspektrum. RésuméOn a étudié les réactions des atomes de recul de carbone-14 sur l'acétanilide irradié aux neutrons. Les mécanismes des réactions intervenant pour la forme solide sont discutés et comparés aux mécanismes observés pour les formes de gaz et liquide. L'hypothèse de la «fragmentation au hasard» semble offrir une explication adéquate. La plupart des produits identifiés résultent de différents processus de recombinaison qui se sont produits entre les radicaux formés à la suite d'une importante fragmentation du produit irradié. L'acétanilide marqué au 14 C a été obtenu avec un rendement radiochimique élevé. Les rendements radiochimiques étaient plus grands pour les produits synthétiques simples que pour les produits plus compliqués. On n'a pas trouvé de dérivés méthyliques marqués. En ce qui concerne les bandes des spectres d'adsorption, l'analyse infrarouge du polymère isolé a mis en évidence une ressemblance profonde avec les polymères observés dans le spectre de l'acétanilide pur, exception faite de l'apparition éventuelle de groupes -CH S -dans le sp...

show abstract

Investigation of the polymers formed in reactor irradiated benzene or toluene together with A1N

Barakat

Abdel-Kerim

1971

Journal of Inorganic and Nuclear Chemistry

View full text Add to dashboard Cite

Investigation of the Reactions of the Recoil Carbon-14 Atoms in Some Heterogeneous Mixtures

Cited by 3 publications

References 10 publications

Investigation of the Polymers Formed in Reactor Irradiated Aniline and Pyridine

Investigation of the Polymers Formed in Reactor Irradiated Aniline and Pyridine

Chemical Effects Associated with the Thermal Neutron Irradiation of Solid Acetanilide (Antifibrin)

Investigation of the polymers formed in reactor irradiated benzene or toluene together with A1N

Contact Info

Product

Resources

About