Intramolecular Rearrangements of Hydrocarbon Radicals in the Gas Phase

Stepukhovich, A.D.; Babayan, V I

doi:10.1070/rc1972v041n09abeh002090

Cited by 5 publications

(2 citation statements)

References 49 publications

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“…In a series of papers from the 1960s on strategically deuterated, isopropyl and isobutyl radicals, Jackson and McNesby − set upper limits on the amount of 1,2 H-shifts and C–H β-scission at (472 to 813) K of 7% for isopropyl and 1% for isobutyl and argued that these upper limits were lower than other literature values because their experiments were free from nonthermal photochemistry . Multiple other researchers claimed significant 1,2 H-shift branching ratios for decades afterward. − ,, These claims were usually based, however, on the detection of compounds that could easily be produced from side chemistry, including methane and ethene. , …”

Section: Discussionmentioning

confidence: 99%

“…9 Multiple other researchers claimed significant 1,2 H-shift branching ratios for decades afterward. [24][25][26]78,79 These claims were usually based, however, on the detection of compounds that could easily be produced from side chemistry, including methane and ethene. 24,25 More recent experimental work by Yamauchi et al 23 in 1999 provides strong evidence against 1,2 H-shifts and competitive C−H β-scissions.…”

Section: Discussionmentioning

confidence: 99%

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β-Bond Scission and the Yields of H and CH₃ in the Decomposition of Isobutyl Radicals

Mertens

Manion

2018

J. Phys. Chem. A

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The relative rates of C-C and C-H β-scission reactions of isobutyl radicals (2-methylprop-1-yl, CH) were investigated with shock tube experiments at temperatures of (950 to 1250) K and pressures of (200 to 400) kPa. We produced isobutyl radicals from the decomposition of dilute mixtures of isopentylbenzene and observed the stable decomposition products, propene and isobutene. These alkenes are characteristic of C-C and C-H bond scission, respectively. Propene was the main product, approximately 30 times more abundant than isobutene, indicating that C-C β-scission is the primary pathway. Uncertainty in the ratio of [isobutene]/[propene] from isobutyl decomposition is mainly due to a small amount of side chemistry, which we account for using a kinetics model based on JetSurF 2.0. Our data are well-described after adding chemistry specific to our system and adjusting some rate constants. We compare our data to other commonly used kinetics models: JetSurF 2.0, AramcoMech 2.0, and multiple models from Lawrence Livermore National Laboratory (LLNL). With the kinetics model, we have determined an upper limit of 3.0% on the branching fraction for C-H β-scission in the isobutyl radical for the temperatures and pressures of our experiments. While this agrees with previous high quality experimental results, many combustion kinetics models assume C-H branching values above this upper limit, possibly leading to large systematic inaccuracies in model predictions. Some kinetics models additionally assume contributions from 1,2-H shift reactions-which for isobutyl would produce the same products as C-H β-scission-and our upper limit includes possible involvement of such reactions. We suggest kinetics models should be updated to better reflect current experimental measurements.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

β-Bond Scission and the Yields of H and CH₃ in the Decomposition of Isobutyl Radicals

Mertens

Manion

2018

J. Phys. Chem. A

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Reactions of acetylene with D atoms and CD3 radicals at high temperatures

Yampolskii

1976

Russ Chem Bull

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Regularities of three-dimensional mechanobreakdown of polymers involving a radical-chain kinetic scheme

Deyun¹,

Манелис²,

Смирнов³

1980

Polymer Science U.S.S.R.

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Intramolecular Rearrangements of Hydrocarbon Radicals in the Gas Phase

Cited by 5 publications

References 49 publications

β-Bond Scission and the Yields of H and CH₃ in the Decomposition of Isobutyl Radicals

β-Bond Scission and the Yields of H and CH₃ in the Decomposition of Isobutyl Radicals

Reactions of acetylene with D atoms and CD3 radicals at high temperatures

Regularities of three-dimensional mechanobreakdown of polymers involving a radical-chain kinetic scheme

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Intramolecular Rearrangements of Hydrocarbon Radicals in the Gas Phase

Cited by 5 publications

References 49 publications

β-Bond Scission and the Yields of H and CH3 in the Decomposition of Isobutyl Radicals

β-Bond Scission and the Yields of H and CH3 in the Decomposition of Isobutyl Radicals

Reactions of acetylene with D atoms and CD3 radicals at high temperatures

Regularities of three-dimensional mechanobreakdown of polymers involving a radical-chain kinetic scheme

Contact Info

Product

Resources

About

β-Bond Scission and the Yields of H and CH₃ in the Decomposition of Isobutyl Radicals

β-Bond Scission and the Yields of H and CH₃ in the Decomposition of Isobutyl Radicals