Effect of Additives on the Ionic Reaction Mechanism in the Radiolysis of Methane

Ausloos, P.; Lias, Sharon G.; Gorden, R.

doi:10.1063/1.1734199

Cited by 56 publications

(19 citation statements)

References 15 publications

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“…where Y i (= 100×[ G i / G (C n H 5 + )])13 is the absolute percent yield of i ‐nth product relative to the starting I , Σ=Y 2 +Y 3 +Y 4 , and τ is the collision time between the arenium ions and B=(C 2 H 5 ) 3 N ( τ =( k coll [B]) −1 ) at the given temperature 14…”

Section: Resultsmentioning

confidence: 99%

Isomeric Alkyl Cation/Arene Complexes in the Gas Phase

Filippi

Roselli

Renzi

et al. 2003

Chemistry A European J

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The kinetics and the stereochemistry of the protonation-induced unimolecular isomerization of (S)-(+)-1-D(1)-3-(p-tolyl)butane have been investigated in the gas phase in the 100-160 degrees C range. The process leads to the almost exclusive formation of the relevant meta isomer with complete racemization and partial 1,2-H shift in the migrating sec-butyl group. These results, together with the relevant activation parameters, point to the occurrence of low-energy, tightly bound isomeric sec-butyl cation/toluene complexes of defined structure and stability along the isomerization coordinate. The existence and the eta(1)-type structure of these low-energy intermediate species are confirmed by ab initio calculations on closely related systems at the MP2(full)/6-311++G**//HF/6-31+G** level of theory. Their role in the relevant energy surface clearly emerges from the comparison of the present results with those concerning sec-butylation of toluene carried out under comparable experimental conditions.

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Section: Resultsmentioning

confidence: 99%

Isomeric Alkyl Cation/Arene Complexes in the Gas Phase

Filippi

Roselli

Renzi

et al. 2003

Chemistry A European J

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“…The mode of C2Hg decomposition may depend on the multiplicity of the CH2 radical, just as the products of CM2 addition to the double bond of butene-2 are a function of methylene multiplicity.23~ 24 Reactions ( 9)-( 12) have been postulated 149 25-27 to account for results obtained under various conditions of photolysis and radiolysis, reactions (lo), (11) or (12) being favoured in accordance with the particular observations. Methylene radicals produced by photolysis of diazomethane were assumed 27 to react via eqn.…”

Section: Ch4(1?'2)+ch2(1a)+h2('c+)mentioning

confidence: 89%

Radiolysis of gaseous mixtures of methane with argon or xenon

Hummel¹

1966

Trans. Faraday Soc.

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Mixtures of CH4 with Ar or Xe have been irradiated with 4 MeV electrons at ambient temperatures and atmospheric pressure. Variations of the yields of H2 and low-molecular-weight hydrocarbons with mixture composition are discussed in terms of the reactions of ions and of excited states. Energy transfer from excited Ar atoms to CH4, resulting in methylene radical and molecular H2 formation, appears to account for more than half the enhanced yields of H2 observed in mixtures of Ar and CW4. Charge transfer processes can account for the rest. The variations in the yields of hydrocarbon products are also consistent with this type of energy transfer mechanism Evidence for energy transfer from excited Xe atoms to CH4 is also given.

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“…Addition of small amounts of isobutane to ca drastically reduces <I>(C2a) both in the neon and helium resonance experiments (tables 1 and 2). This reduction which is accompanied by a corresponding increase of <I>(C2H6) in the presence or in the absence of O2 is to be accounted for [17] by the removal of the C2Ht ion via the hydride ion transfer reaction Formation of C2H(; in reaction 12 is substantiated by the fact that more than 90 oercent of thp. p. th anp.…”

Section: B Formation Of Ethylenementioning

confidence: 96%

Photochemistry of methane in the photoionization region

Rebbert

Ausloos

1973

J. RES. NATL. BUR. STAN. SECT. A.

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Methane was irradiated with microwave operated helium (21.2 eV) and neon (16.7-16.8 eV) resonance lamps whi ch were separated from the reaction vessel by an aluminum window. The quantum yields of the stable end products hav e been dete rmin ed at methane pressures ranging from 1 to 20 torr. Over thi s pressure ran ge the ab und ances of the primary ions, dete rmined throu gh various diagnostic expe riments, are within experim ental error the sa me at 21.2 eV as at 16_7 -16.8 eV ItC H; = CH t = 0.5, CH:; ~ 0.02), and are in good agree ment with th e primary mass s pectra obtained in a photoionization mass s pectrometer und er collision free condition s (P < 10-5 torr). The C,Ht whi ch is form ed by the reaction: CHt + CH. ~ C,Ht + Hz loses a proton by an undetermined mec hanism to give C,H. as a product.There is no evid ence for the formation of neutral fragm ents such as H2 , C, CH or CH, at 16.7-U,,8 eV. The fact that the ionization quantum is equal to unity in thi s e nergy range accounts for the absence of these intermediates. At 21.2 eV wh ere (

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Effect of Additives on the Ionic Reaction Mechanism in the Radiolysis of Methane

Cited by 56 publications

References 15 publications

Isomeric Alkyl Cation/Arene Complexes in the Gas Phase

Isomeric Alkyl Cation/Arene Complexes in the Gas Phase

Radiolysis of gaseous mixtures of methane with argon or xenon

Photochemistry of methane in the photoionization region

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