Electron scavenging in the γ-radiolysis of tetrahydrofuran

Kadhum, Abdul Amir H.; Salmon, G. Arthur

doi:10.1016/0146-5724(84)90094-3

Cited by 7 publications

(3 citation statements)

References 19 publications

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“…1 three compounds, namely pyrimidine ( 9 , p-tetrachlorobenzoquinone (1 8) and 2,2'-diphenylpicrylhydrazyl ( 19), are somewhat displaced from the general trends of the graph. Possible reasons for this could be that: (i) the reported E+ values are in error and (ii) reaction (1) yields an excited state of the solute radical anion for solutes (18) and…”

Section: Dependence On Electron Affinity Of Solutementioning

confidence: 99%

Reactivity of solvated electrons in tetrahydrofuran

Kadhum¹,

Salmon²

1986

J. Chem. Soc., Faraday Trans. 1

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The rates of reaction of solvated electrons (e;) with 23 solutes have been measured in tetrahydrofuran at 22 & 1 "C. The values range from (1.5 _+ 0.4) x lo9 dm3 mol-1 s-l for phenol to (1.56k0.01) x lo1' dm3 mol-1 s-l for benzonitrile. It is concluded that the diffusion-controlled rate constant for reactions of e; in this solvent is ca. 1.7 x 10" dm3 mol-l s-l, which indicates that the sum of the reaction radii of e; and the solute is ca. 1.67 nm. This value is close to the value of 1.38 nm, estimated for the maximum reaction radius of e-in the gas phase. The effect of AG* for the reaction on the rate constant is investigated and evidence is presented for an inversion in the rate in the highly exergonic region, although a few solutes deviate from the general trend. The temperature dependence of the rate constants for five solutes has been measured and the values of the activation energy lie in the range 11.7-15.4 kJ mol-I. It is concluded that the rate constants for the electron-scavenging process qualitatively conform to the predictions of quantum-mechanical theories for electron-transfer reactions.

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Section: Dependence On Electron Affinity Of Solutementioning

confidence: 99%

Reactivity of solvated electrons in tetrahydrofuran

Kadhum¹,

Salmon²

1986

J. Chem. Soc., Faraday Trans. 1

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“…Saeki notes that this yield may be low, suggesting that the capture of presolvated electrons that might have otherwise recombined with holes prior to solvation make up the difference . Such a suggestion might be supported by older work by Kadhum using electron scavengers, that concluded a total yield of 4.0/100 eV . Saeki’s results with biphenyl concentrations up to 2 M do not appear to support such a substantial increase, however, and the small increases observed may be due to production of biphenyl radical cations in light of the work in this paper, and as discussed in the following.…”

Section: Discussionmentioning

confidence: 54%

Sub-picosecond Production of Solute Radical Cations in Tetrahydrofuran after Radiolysis

Cook

2021

J. Phys. Chem. A

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Ultrafast hole transfer from solvent radical cations produced by radiolysis with ∼10 ps, 9 MeV electron pulses to solutes in tetrahydrofuran (THF) was investigated. Because of rapid fragmentation of initially produced THF +• , solute radical cations are not expected and have not previously been reported. When 9,9-dihexyl-2,7-dibromofluorene (Br 2 F) at 5 to 1000 mM was used, Br 2 F +• with radiation chemical yields up to G = 2.23/100 eV absorbed was observed. While more than half of this was the result of direct solute ionization, the results highlight the importance of capturing holes from THF +• prior to solvation and fragmentation. The observed data show a time-resolution limited (15 ps) rise in transient absorption of Br 2 F +• , identical in form to reports of presolvated or dry electron capture in water and a few organic liquids, including THF. The results were thus interpreted with a similar formalism, finding C 37 = 1.7 M, the concentration at which 37% of holes escape capture. The yield of solvent hole capture can be accounted for by the formation of solvent holes adjacent to solute molecules reacting faster than they can fragment; however, mechanisms such as delocalized holes or rapid hopping may play a role. Low temperature results find over two times more capture, supporting the speculation that if THF +• was longer lived, the yield of capture in under 15 ps would have been at least 2 times larger at 1 M Br 2 F, possibly capturing nearly all available holes from the solvent.

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“…The yields of CH4 and C2H6 were formed due to this mechanism: For low concentration of CH3Br (1.51 x le to 0.13 mol. r1) GeK =0.338 ± 0.17 , G9 , =3.82 ± 0.24 and a =19.8 ± 3.4 [31].…”

Section: 2-alkyl Halidesmentioning

confidence: 92%

Mechanism of Organic Reactions Under the Effect of Radiolysis

El-Dessouky

2001

International Conference on Aerospace Sciences and Aviation Tec

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The mechanism of interaction of radiation especially with organic material explains the ways of optimum utilization of nuclear energy and to avoid its harmful effects. Nowadays three principal mechanisms are adopted to interpret the formation of radiolytic products. These three principal mechanisms are: free radical mechanism, excited state mechanism and interaction with solvated electrons. The presence of atmospheric oxygen, impurities, scavengers, as well as type of solvent, type of radiation, dose and dose rate affect on the mechanism of the radiolytic reaction. The adopted mechanisms are supposed according to the experimental found free radicals and radiolytic products. The review collected most adopted mechanisms for the most important organic compounds. Summarized mechanisms for radiolysis of hydrocarbons , alkyl halides , olefins , unsaturated and aromatic hydrocarbons , alcohols , organic acids are shown. Also the mechanism of radiolysis of aqueous solutions of some organic compounds is offered. Finally some important technological applications of radiation a: e offered.

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Electron scavenging in the γ-radiolysis of tetrahydrofuran

Cited by 7 publications

References 19 publications

Reactivity of solvated electrons in tetrahydrofuran

Reactivity of solvated electrons in tetrahydrofuran

Sub-picosecond Production of Solute Radical Cations in Tetrahydrofuran after Radiolysis

Mechanism of Organic Reactions Under the Effect of Radiolysis

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