Radiation Chemistry of Mixtures. Cyclohexane and Benzene-<sup>d6</sup>

Burton, Milton; Patrick, W. N.

doi:10.1021/j150515a010

Cited by 35 publications

(24 citation statements)

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“…However, we chose to neglect it in this treatrllellt since its effects are small. The values of the specific reaction rate constants chosen for reactions [4] and [5] are in agreement with the theory of bimolecular combination of two radicals (8 energy. k 3 and the pre-exponential term in k~ \Irere chosen slightly lower than would be predicted theoretically in order to keep the value of kz (which as calculated depends on k3 and kl) ell below the rate of collision between two particles.…”

Section: Discussionsupporting

confidence: 74%

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The Reactions of Hydrogen Atoms With Some Organic Liquids

Ingalls¹,

Hardy²

1960

Can. J. Chem.

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Measurements have been made o f isotopic exchange and deuteriu~n pressure change during deuterium atom bombardment o f o-terphenyl, toluene, and eicosane just above their melting points. T h e number o f molecules o f H D formed was larger than the number o f molecules lost or gained b y the gas phase. +% nmechanism o f reaction o f deuterium atoms w i t h aromatic liquids is proposed. INTRODUCTIOSDuring studies of the radiatio~i chenlistry of sollie aromatic liquids (I), a need for a better understanding of the reactions of hydrogen atoms with aromatic ~liolecules became apparent. There have been a number of studies of the action of hydrogen or deuterium atoms with aromatic or clouble-bond systems in the gas and solid phases reported (2), but reactions of hydrogen atonis in organic liquids have been largely neglected. Experimental difficulties encountered in such studies Inay be in part respo~isible for this state of affairs.Hydrogen atoms are important intermediates in the radiation-induced formation of both high ~nolecular weight products and hydrogen gas in aromatic and vinyl hydrocarbon systems (3).Therefore, a knowledge of their reactions is necessary for an understanding of the radiation chemistry of these materials. X knowledge of hydrogen atom reactions ~vould also contribute indirectly to our knowledge of energy transfer and other important processes in radiation chemistry by allowing the separation of these reactions fro111 other effects (4).The work reported here is part of an effort to gain better understancling of the reactions of hydrogen atoms with aromatic matel-ials by clirectexperimentation. Purified deuterium gas was dissociated into atoms on a hot tungsten filament. The gas, containing a small fraction of atoms, was cooled by indirect ~nomentum transfer with thermostatted malls of the reaction vessel before impinging on the surface of the liquicl under investigation. The gas consumed or formed during the reaction was measured, and the formation of H D was deteniiined by mass spectroscopy.Deuterium gas, obtained from Stuart Oxygcn Compa~iy, mas further purified by storage as uranium deutericle. Its isotopic purity mas determinecl by mass spectroscopy to be 99.5%.Reagent grade toluene, obtained froni l/Iallincl;rodt, was distilled through a 2 5 f t glass-helix packed column and dried over c a l c i~~m liyclricle. S o impurities were detectable by gas-liquid partition chro~natograpliy.Eastman I

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Section: Discussionsupporting

confidence: 74%

“…Thus, these results may be accounted for by the ~nechanism proposed in this paper. 4. During radiolysis experiments a t low hydrogen atom initiation rates, exchange with perdeutero aromatic additives occurs t o a very limited extent (17).…”

Section: D-= F D X T H E Nz~?izerical Value Of D Tlze Ficks Law Difmentioning

confidence: 99%

The Reactions of Hydrogen Atoms With Some Organic Liquids

Ingalls¹,

Hardy²

1960

Can. J. Chem.

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“…Yields of H 2 as a function of the percentage of benzene in cyclohexane for 185 nm UV, γ-ray, and 5 MeV 4 He radiolysis along with previous γ-ray results. 8 The dashed line shows the expected result using the mixture law.…”

Section: ■ Results and Discussionmentioning

confidence: 81%

Combinations of Aromatic and Aliphatic Radiolysis

LaVerne

Dowling-Medley

2015

J. Phys. Chem. A

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The production of H(2) in the radiolysis of benzene, methylbenzene (toluene), ethylbenzene, butylbenzene, and hexylbenzene with γ-rays, 2-10 MeV protons, 5-20 MeV helium ions, and 10-30 MeV carbon ions is used as a probe of the overall radiation sensitivity and to determine the relative contributions of aromatic and aliphatic entities in mixed hydrocarbons. The addition of an aliphatic side chain with progressively from one to six carbon lengths to benzene increases the H(2) yield with γ-rays, but the yield seems to reach a plateau far below that found from a simple aliphatic such as cyclohexane. There is a large increase in H(2) with LET (linear energy transfer) for all of the substituted benzenes, which indicates that the main process for H(2) formation is a second-order process and dominated by the aromatic entity. The addition of a small amount of benzene to cyclohexane can lower the H(2) yield from the value expected from a simple mixture law. A 50:50% volume mixture of benzene-cyclohexane has essentially the same H(2) yield as cyclohexylbenzene at a wide variation in LET, suggesting that intermolecular energy transfer is as efficient as intramolecular energy transfer.

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“…BURTON and PATRICK [45] have shown that the reduction of G(H 2 ) in alkane + benzene mixtures can not be attributed to scavenging of Η atom acc. to :…”

Section: Discussionmentioning

confidence: 99%

Inter- and Intramolecular Energy Transfer in Gammaradiolysis of n-Alkylbenzenes

Zeman¹,

Heusinger²

1967

Radiochimica Acta

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Hydrogen production in y-irradiated ii-alkylbenzenes (toluene to heptadecylbenzene), in isomeric η -alkylbenzenes and Ji-alkylbenzenes-d 5 was investigated. Radicals formed at 77 °K were identified by EPR-spectroscopy and their G-values measured. A mechanism for the formation of hydrogen, based on ion-molecule reactions and hot atom reactions, is proposed. The low G(H 2 ) und G(R) values of the various ra-alkylbenzenes indicate that the phenyl group protects the alkyl group, with respect to hydrogen and radical formation. Energy transfer was suggested to explain the results. A MARKOV chain approach shows that energy transfer from the aliphatic chain to the phenyl group is 13 times as probable as the dissociation of a C-Η bond and the desactivation of the excited state involved. To separate inter-and intramolecular energy transfer, a similar investigation with alkane/benzene mixtures was carried out. The probability for energy transfer from the alkane chain to the benzene molecule was found to be 10 times as probable as the two other reactions. The results suggest that in n-alkylbenzenes besides intermolecular transfer also intramolecular transfer takes place, with comparable efficiency.Zusammenfassung DieWasserstoff bildung in y-bestrahlten ra-Alkylbenzolen (Toluol bis Heptadecylbenzol), in isomeren w-Alkylbenzolen und w-Alkylbenzolen-d 6 , wurde untersucht. Die bei 77 °K gebildeten Radikale wurden EPRspektroskopisch identifiziert und ihre G-Werte gemessen. Die Untersuchungen zeigen, daß Wasserstoff über Ionen-Molekülreaktionen und Abstraktionsreaktionen heißer Η-Atome gebildet wird. Die G-Werte für die Wasserstoff-und Radikalbildung sind stets kleiner als nach der Additivitätsregel berechnet. Dies zeigt: die Phenylgruppe vermag die Alkylgruppe zu schützen. Wir machen Energieübertragung für diesen Schutz verantwortlich. Es wurde gezeigt, daß sich die Vorgänge bei der Energieübertragung als eine MARKOV Kette von Ereignissen darstellen lassen. Aus dieser Behandlung ergibt sich, daß Energieübertragung von der aliphatischen Kette in den Phenylkern dreizehnmal häufiger ist als die Dissoziation einer C-Η-Bindung und Desaktivierung des angeregten Zustande in der Kette. Um zu klären, ob die Energieübertragung intra-oder intermolekular erfolgt, wurden analoge Untersuchungen an Alkan/Benzolmischungen durchgeführt. Der Energieübergang von der aliphatischen Kette ist in diesem Fall zehnmal so häufig als die beiden anderen Reaktionen. In w-Alkylbenzolen findet also neben einer intermolekularen Energieübertragung eine vergleichbare intramolekulare Über-tragung statt. ResumeOn examine la production d'hydrogene dans des «.-alkyl-benzenes (toluene a heptadecylbenzene) soumis aux radiations γ ainsi que dans les isomeres »-alcyl-benzenes et »-alkyl-benzenes-d 5 .Les radicaux formes vers 77 °K ont ete identifies par spectroscopie EPR et les rendements G mesures. On propose un mecanisme de formation de l'hydrogene par reactions ions-molecules et reactions d'atomes chauds. Les valeurs faibles des G trouves pour la formation de l'hydro...

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Radiation Chemistry of Mixtures. Cyclohexane and Benzene-^d6

Cited by 35 publications

References 0 publications

The Reactions of Hydrogen Atoms With Some Organic Liquids

The Reactions of Hydrogen Atoms With Some Organic Liquids

Combinations of Aromatic and Aliphatic Radiolysis

Inter- and Intramolecular Energy Transfer in Gammaradiolysis of n-Alkylbenzenes

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Radiation Chemistry of Mixtures. Cyclohexane and Benzene-d6

Cited by 35 publications

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The Reactions of Hydrogen Atoms With Some Organic Liquids

The Reactions of Hydrogen Atoms With Some Organic Liquids

Combinations of Aromatic and Aliphatic Radiolysis

Inter- and Intramolecular Energy Transfer in Gammaradiolysis of n-Alkylbenzenes

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Product

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Radiation Chemistry of Mixtures. Cyclohexane and Benzene-^d6