Strahlungschemie von Kolhenwasserstoffen 10. Mitteilung Let‐Effekte in Toluol

Hoigné, Jürg; Burns, W. G.; Marsh, W.R.; Gäumann, Tino

doi:10.1002/hlca.19640470132

Cited by 7 publications

(3 citation statements)

References 13 publications

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“…Previous work has shown that the major products in radiolysis of toluene are hydrogen and dimeric materials mainly consisting of bibenzyl, bitolyls, and benzyltoluenes. − The rupture of C–H bonds on the methyl group is the dominant process, leading to the formation of bibenzyl . The overall reaction for toluene giving rise to molecular hydrogen and bibenzyl (see Supporting Information for a discussion on the production of major products in radiolysis of toluene and their interaction with Pd 2+ ions) would be …”

Section: Resultsmentioning

confidence: 99%

Gaining Control over Radiolytic Synthesis of Uniform Sub-3-nanometer Palladium Nanoparticles: Use of Aromatic Liquids in the Electron Microscope

Abellán

Parent

Hasan³

et al. 2016

Langmuir

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Synthesizing nanomaterials of uniform shape and size is of critical importance to access and manipulate the novel structure-property relationships arising at the nanoscale, such as catalytic activity. In this work, we synthesize Pd nanoparticles with well-controlled size in the sub-3 nm range using scanning transmission electron microscopy (STEM) in combination with an in situ liquid stage. We use an aromatic hydrocarbon (toluene) as a solvent that is very resistant to high-energy electron irradiation, which creates a net reducing environment without the need for additives to scavenge oxidizing radicals. The primary reducing species is molecular hydrogen, which is a widely used reductant in the synthesis of supported metal catalysts. We propose a mechanism of particle formation based on the effect of tri-n-octylphosphine (TOP) on size stabilization, relatively low production of radicals, and autocatalytic reduction of Pd(II) compounds. We combine in situ STEM results with insights from in situ small-angle X-ray scattering (SAXS) from alcohol-based synthesis, having similar reduction potential, in a customized microfluidic device as well as ex situ bulk experiments. This has allowed us to develop a fundamental growth model for the synthesis of size-stabilized Pd nanoparticles and demonstrate the utility of correlating different in situ and ex situ characterization techniques to understand, and ultimately control, metal nanostructure synthesis.

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Section: Resultsmentioning

confidence: 99%

Gaining Control over Radiolytic Synthesis of Uniform Sub-3-nanometer Palladium Nanoparticles: Use of Aromatic Liquids in the Electron Microscope

Abellán

Parent

Hasan³

et al. 2016

Langmuir

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“…Hence, bibenzyl produced upon irradiation of toluene derives almost entirely from a radical precursor, the benzyl radical. Benzyl radical, in turn, is thought to be formed due to the decay of excited state molecules of toluene . Irradiation of toluene under collision-free conditions at 193 nm showed that α-H• atom elimination and CH 3 elimination are the major dissociation channels (cf.…”

Section: Resultsmentioning

confidence: 99%

“…Benzyl radical, in turn, is thought to be formed due to the decay of excited state molecules of toluene. 71 Irradiation of toluene under collision-free conditions at 193 nm showed that R-H• atom elimination and CH 3 elimination are the major dissociation channels (cf. reactions 1À2):…”

Section: ' Results and Discussionmentioning

confidence: 99%

Role of the Low-Energy Excited States in the Radiolysis of Aromatic Liquids

2011

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The contribution of the low-energy excited states to the overall product formation in the radiolysis of simple aromatic liquids--benzene, pyridine, toluene, and aniline--has been examined by comparison of product yields obtained in UV-photolysis and in γ-radiolysis. In photolysis, these electronic excited states were selectively populated using UV-light excitation sources with various energies. Yields of molecular hydrogen and of "dimers" (biphenyl, bibenzyl, dipyridyl for benzene, toluene, pyridine, respectively, and of ammonia and diphenylamine for aniline) have been determined, since they are the most abundant radiolytic products. Negligibly small production of molecular hydrogen in the UV-photolysis of aromatic liquids with excitation to energies of 4.88, 5.41, 5.79, and 6.70 eV and the lack of a scavenger effect suggest that this product originates from short-lived high-energy singlet states. A significant reduction in "dimer" radiation-chemical yields in the presence of scavengers such as anthracene or naphthalene indicates that the triplet excited states are important precursors to these products. The results for toluene and aniline suggest that efficient dissociation from the lowest-energy excited triplet state leads to noticeable "dimer" production. For benzene and pyridine, the lowest-energy triplet excited states are not likely to fragment into radicals because of the relatively large energy gap between the excited state level and corresponding bond dissociation energy. The "dimer" formation in the radiolysis of benzene and pyridine is likely to involve short-lived high-energy triplet states.

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Strahlungschemie der Kohlenwasserstoffe. 12. Mitteilung. Benzol‐Toluol und deuterierte Verbindungen

Hoigné

Gäumann

1964

Helvetica Chimica Acta

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Further information on the radiation chemistry of aromatic liquids has been obtained by a detailed analysis applied mainly to the dimeric products formed by the gamma irradiation of mixtures of benzeneltoluene and their deutero‐compounds (benzene‐d6toluene‐d0 and benzene‐d0/toluene‐α‐d3). The diphenylmethane‐type of molecules are not formed by a reaction of dehydroaromatic species (benzyne). The different products are generally produced according the expected mixture law when corrections for the competing chemical reactions are allowed for. In the perdeutero‐benzenel/toluene system however an energy transfer from benzene‐d6, to toluene must be postulated to explain the yields obtained. The isomer distribution of the three phenyltoluenes can be compared with the statistical values.

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Strahlungschemie von Kolhenwasserstoffen 10. Mitteilung Let‐Effekte in Toluol

Cited by 7 publications

References 13 publications

Gaining Control over Radiolytic Synthesis of Uniform Sub-3-nanometer Palladium Nanoparticles: Use of Aromatic Liquids in the Electron Microscope

Gaining Control over Radiolytic Synthesis of Uniform Sub-3-nanometer Palladium Nanoparticles: Use of Aromatic Liquids in the Electron Microscope

Role of the Low-Energy Excited States in the Radiolysis of Aromatic Liquids

Strahlungschemie der Kohlenwasserstoffe. 12. Mitteilung. Benzol‐Toluol und deuterierte Verbindungen

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