Experimental and modeling study of the oxidation of 1‐butyne and 2‐butyne

Belmekki, Najib; Glaude, Pierre‐Alexandre; Costa, Isabelle Da; Fournet, René; Battin‐Leclerc, Frédérique

doi:10.1002/kin.10035

Cited by 40 publications

(88 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast, when Robinson et al 24 photodissociated 1,2-butadiene at 193 nm, they observed a P(E T ) for the C-C fission channel that peaked at 5 kcal/mol and extended to 27 kcal/mol, as shown in Figure 5 The 1-buten-2-yl radical acts as an intermediate in such reactions as the methyl-initiated pyrolysis of allene, investigated by Goos et al, 8 and the oxidation of 1-butyne, studied by Belmekki et al 9 The 1-buten-2-yl radical is not explicitly mentioned in the latter study but is the intermediate in reaction 5 of Table III in that work, 1-C 4 H 6 f CH 3 + aC 3 H 4 . In modeling this reaction, Belmekki et al used Arrhenius parameters derived for the analogous reaction of propyne, H + propyne f 2-propenyl f H + allene.…”

Section: Discussionmentioning

confidence: 93%

See 1 more Smart Citation

Dissociation Channels of the 1-Buten-2-yl Radical and Its Photolytic Precursor 2-Bromo-1-butene

et al. 2005

View full text Add to dashboard Cite

The work presented here is the first in a series of studies that use a molecular beam scattering technique to investigate the unimolecular reaction dynamics of C 4 H 7 radical isomers. Photodissociation of the halogenated precursor 2-bromo-1-butene at 193 nm under collisionless conditions produced 1-buten-2-yl radicals with a range of internal energies spanning the predicted barriers to the unimolecular reaction channels of the radical. Resolving the velocities of the stable C 4 H 7 radicals, as well as those of the products, allows for the identification of the energetic onset of each dissociation channel. The data show that radicals with at least 30.7 ( 2 kcal/ mol of internal energy underwent C-C fission to form allene + methyl, and radicals with at least 36.7 ( 4 kcal/mol of internal energy underwent C-H fission to form H + 1-butyne and H + 1,2-butadiene; both of these observed barriers agree well with the G3//B3LYP calculations of Miller. HBr elimination from the parent molecule was observed, producing vibrationally excited 1-butyne and 1,2-butadiene. In the subsequent dissociation of these C 4 H 6 isomers, the major channel was C-C fission to form propargyl + methyl, and there is also evidence of at least one of the possible H + C 4 H 5 channels. A minor C-Br fission channel produces 1-buten-2-yl radicals in an excited electronic state and with low kinetic energy; these radicals exhibit markedly different dissociation dynamics than do the radicals produced in their ground electronic state.

show abstract

Section: Discussionmentioning

confidence: 93%

“…8,9 Kinetics experiments provide useful data with which to compare predictions of microcanonical rate constants and ab initio barrier heights. However, modeling such experiments requires the use of master equations to describe the adduct formation and complex energy transfer processes also contributing to the bulk measurements.…”

Section: Introductionmentioning

confidence: 99%

Dissociation Channels of the 1-Buten-2-yl Radical and Its Photolytic Precursor 2-Bromo-1-butene

et al. 2005

View full text Add to dashboard Cite

show abstract

“…This mechanism is an improvement of our previous mechanism that was built to model the oxidation of C 3 -C 4 unsaturated hydrocarbons [8,15] to better take into account the reactions of allene, propyne and propargyl radicals.…”

Section: Description Of the Proposed Mechanismmentioning

confidence: 99%

“…The main addition to the reactions of allene was to consider the reactions of abstraction of a hydrogen atom by H atoms and OH, CH 3 , C 2 H, C 2 H 3 , C 2 H 5 and a-C 3 H 5 radicals (reactions [15][16][17][18][19][20][21][22]. These reactions, involving the abstraction of vinylic H-atoms, had been neglected in our previous work in shock tube conditions [8], but were found important here to correctly reproduce the profile of allene in the flame doped with this compound.…”

Section: Table Imentioning

confidence: 99%

“…The use of a methane flame will allow us to have a reactive mixture rich in methyl radicals and to be more representative of combustion mixtures containing larger hydrocarbons than hydrogen or C 2 flames. These results have been used to improve the mechanism previously developed in our laboratory for the reactions of C 3 -C 4 unsaturated hydrocarbons (propyne, allene, 1-butyne, 2-butyne, 1,3-butadiene) [8,15]. …”

mentioning

confidence: 99%

See 1 more Smart Citation

Rich methane premixed laminar flames doped with light unsaturated hydrocarbonsI. Allene and propyne

Gueniche

Glaude

Dayma

et al. 2006

Combustion and Flame

View full text Add to dashboard Cite

The structure of three laminar premixed rich flames have been investigated: a pure methane flame and two methane flames doped by allene and propyne, respectively. The gases of the three flames contain 20.9% (molar) of methane and 33.4 % of oxygen corresponding to an equivalent ratio of 1.25 for the pure methane flame. In both doped flames, 2.49 % of C 3 H 4 was added, corresponding to a ratio C 3 H 4 / CH 4 of 12 % and an equivalent ratio of 1.55. The three flames have been stabilized on a burner at a pressure of 6.7 kPa using argon as dilutant, with a gas velocity at the burner of 36 cm/s at 333 K. The concentration profiles of stable species were measured by gas chromatography after sampling with a quartz microprobe. Quantified species included carbon monoxide and dioxide, methane, oxygen, hydrogen, ethane, ethylene, acetylene, propyne, allene, propene, propane, 1,2-butadiene, 1,3-butadiene, 1-butene, iso-butene, 1-butyne, vinylacetylene and benzene. The temperature was measured using a thermocouple in PtRh (6%)-PtRh (30%) settled inside the enclosure and ranged from 700K close to the burner up to 1850K. In order to model these new results, some improvements have been made to a mechanism previously developed in our laboratory for the reactions of C 3 -C 4 unsaturated hydrocarbons. The main reaction pathways of consumption of allene and propyne and of formation of C 6 aromatic species have been derived from flow rate analyses.Keywords : Premixed laminar flame, methane, allene, propyne, modeling. 3 INTRODUCTIONSoots and polyaromatic hydrocarbons (PAH), which are present in the exhaust gas of diesel engine, represent a high part of the urban pollution. Many efforts have then been focused on reducing the emissions of these compounds. The formation of soot precursors and PAH in combustion involves small unsaturated hydrocarbons, the chemistry of which is still very uncertain. Different reaction pathways have been proposed for the formation and the oxidation of the first aromatic compounds, involving the reactions of C 2 (acetylene), C 3 or C 4 unsaturated species [1][2][3][4][5].As the determinant role of propargyl radicals in forming benzene, the first aromatic ring, is now well accepted, it is important to better understand their reactions. With that purpose, the oxidation of allene (propadiene) and propyne has been already studied in several oxidation conditions: shock tubes [6][7][8], flow reactor [9,10], jet-stirred reactor [7,11] and premixed flames [10,11]. Previous works in flames include studies of the influence of the addition of allene on The purpose of the present paper is to experimentally investigate the structures of two premixed laminar methane flames containing propadiene and propyne, respectively, and to compare them with that of a pure methane flame containing the same mole fractions of methane and oxygen. The use of a methane flame will allow us to have a reactive mixture rich in methyl radicals and to be more representative of combustion mixtures containing larger hydrocarbons than hydrogen or ...

show abstract

Cytopathology of “double‐hit” non‐Hodgkin lymphoma

Elkins

Wakely

2011

Cancer Cytopathology

View full text Add to dashboard Cite

BACKGROUND:B‐cell lymphomas with concurrent IGH‐BCL2 and c‐MYC rearrangements (so‐called “double‐hit lymphomas” [DHL]) are a relatively rare, recently described category in the 2008 World Health Organization classification of hematopoietic neoplasms. Response to chemotherapy and survival are poor.METHODS:The authors reviewed files of cytogenetically documented DHL to identify cytologic features that would allow its possible recognition.RESULTS:Twelve fine‐needle aspirates (FNAs), 2 pleural fluids, and 1 touch imprint of cytogenetically proven DHL were uncovered. Primary DHL was correctly recognized in 3 of 12 FNA cases using Ki‐67 staining coupled with a positive bcl‐2 result as the basis for performing fluorescence in situ hybridization (FISH) analysis of c‐MYC and IGH‐BCL2 rearrangements. Remaining FNAs and non‐FNA cases were diagnosed as non‐Hodgkin lymphoma, B‐cell lymphoma, or atypical lymphocytosis. Ten cases had cell block material available. All cases had high cellularity with a dissociated smear pattern and background lymphoglandular bodies. Cell size ranged from intermediate to large. Nuclei were predominantly rounded or slightly irregular in contour; 4 FNAs had markedly cleaved nuclei. Some nuclei harbored discrete but small nucleoli, whereas in others coarse chromatin and indistinct or multiple small nucleoli existed. A variable number of mitotic figures, tingible body macrophages, and background apoptotic cells were also present.CONCLUSIONS:No specific cytomorphologic feature(s) were found to reliably identify DHL using FNA or exfoliative cytology. A high Ki‐67 proliferation index and positive bcl‐2 staining (on cytospin slides or cell block material) of cases not conforming to typical Burkitt lymphoma morphology should prompt FISH analysis for c‐MYC and/or IGH‐BCL2 rearrangements to identify DHL, particularly if tissue biopsy is not expected. Cancer (Cancer Cytopathol) 2011;. © 2011 American Cancer Society

show abstract

Experimental and modeling study of the oxidation of 1‐butyne and 2‐butyne

Cited by 40 publications

References 35 publications

Dissociation Channels of the 1-Buten-2-yl Radical and Its Photolytic Precursor 2-Bromo-1-butene

Dissociation Channels of the 1-Buten-2-yl Radical and Its Photolytic Precursor 2-Bromo-1-butene

Rich methane premixed laminar flames doped with light unsaturated hydrocarbonsI. Allene and propyne

Cytopathology of “double‐hit” non‐Hodgkin lymphoma

Contact Info

Product

Resources

About