Flash photolysis studies of free-radical reactions: C3H5 + C3H5 (293-691 K) and C3H5 + NO (295-400 K)

Tulloch, James M.; Macpherson, Martyn T.; Morgan, Carol A.; Pilling, Michael J.

doi:10.1021/j100216a021

Cited by 65 publications

(93 citation statements)

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“…Photolysis of Hexa-1,5-Diene Tulloch et al [5] investigated the photolysis of hexa-1,5-diene at 193.3 nm. The primary processes are production of two allyl radicals (68%), production of H and C6H9 (2.5%), production of propene and propadiene (27%), with which H will react only slowly, and formation of CH3 and C5H7 (2.5%).…”

Section: Resultsmentioning

confidence: 99%

“…The major reaction sinks are C3H5 + C3H5, CH3, 0, H, OH, and H02. Direct measurements of C3H5 + C3H5 [5] and C3H5 + CH3 [6] have been reported, as have indirect measurements on C3H5 + H02 [7]. We recently reported studies of C3H5 + 0 over the temperature range 300-500 K, using a combination of laser flash photolysis coupled with absorption spectroscopy plus resonance fluorescence and laser flash photolysis coupled with photoionization mass spectrometry [8].…”

Section: Introductionmentioning

confidence: 95%

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Kinetics of the reaction between H atoms and allyl radicals

Hanning-Lee¹,

Pilling

1992

Int J of Chemical Kinetics

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The reaction between H and C S H~ has been studied at 291 K. Exciplex laser flash photolysis at 193.3 nm of hexa-1,5-diene-He mixtures generated both H and C3H5 ([HI 6 [C~HS]), which were detected in time-resolved mode by resonance fluorescence and absorption spectroscopy, respectively. Rate coefficients are presented at four pressures in the range 98 5 P/torr 5 400; no clear pressure-dependence is found in this range of pressures and the mean rate coefficient is (2.8 f 1.0) x lo-'' cm3 molecule-' s-'. Calculations based on the Troe factorization method confirm that this reaction is near its high-pressure limit under the experimental conditions.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Kinetics of the reaction between H atoms and allyl radicals

Hanning-Lee¹,

Pilling

1992

Int J of Chemical Kinetics

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“…Allyl bromide photolysis produces allyl radicals and bromine atoms whose reactions are comparatively slow and do not interfere with the fast radical-radical/fast atom chemistry [31][32][33]. The photodecomposition of 1,5-hexadiene yields besides two allyl radicals directly propene and allene [15]. In this case, the side reactions of the O atoms with the precursor have to be considered: the reaction of 1,5-hexadiene with oxygen atoms leads to 5-hexenal with minor channels to acrolein and propene as well as to CO and H 2 CO in line with an extensive study of Cvetanovic on olefine + O reactions [34].…”

Section: Product Branchingmentioning

confidence: 99%

“…Since for the allyl radical the unimolcular C-C and C-H bond fission reactions and the reaction with molecular oxygen are significantly slower than for saturated alkyl radicals [11][12][13], the reactions of allyl radicals with atoms (O, H) and other radicals (OH, alkyl) become dominant under high-temperature conditions. Several experimental and theoretical studies have been performed to determine the rate and the products of the title reaction so far [14][15][16][17][18][19]. According to these investigations the reaction allyl + O mainly proceeds via a highly energized allyloxy intermediate, which subsequently undergoes fast decomposition, in analogy to the reactions of alkyl radicals with O atoms [20][21][22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

The reaction of allyl radicals with oxygen atoms—rate coefficient and product branching

Hoyermann¹,

Nacke²,

Nothdurft³

et al. 2009

Proceedings of the Combustion Institute

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“…The flow reactor with laser photolysis coupled to the resonance gas lamp photoionization mass spectrometer (LP-RPIMS) used in this work has been described previously, 15,16 and only a brief 17 Tulloch et al, 11 and most recently by Selby et al 10 The main photolysis channel leads to C3−C4 bond fission, but in addition other products are formed:…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Gas Phase Kinetics and Equilibrium of Allyl Radical Reactions with NO and NO₂

et al. 2013

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Allyl radical reactions with NO and NO 2 were studied in direct, time-resolved experiments in a temperature controlled tubular flow reactor connected to a laser photolysis/photoionization mass spectrometer (LP-PIMS). In the C 3 H 5 + NO reaction 1, a dependence on the bath gas density was observed in the determined rate coefficients and pressure falloff parametrizations were performed. The obtained rate coefficients vary between 0.30− 14.2 × 10 −12 cm 3 s −1 (T = 188−363 K, p = 0.39−23.78 Torr He) and possess a negative temperature dependence. The rate coefficients of the C 3 H 5 + NO 2 reaction 2 did not show a dependence on the bath gas density in the range used (p = 0.47−3.38 Torr, T = 201−363 K), and they can be expressed as a function of temperature with k(C 3 H 5 + NO 2 ) = (3.97 ± 0.84) × 10 −11 × (T/300 K) −1.55±0.05 cm 3 s −1 . In the C 3 H 5 + NO reaction, above 410 K the observed C 3 H 5 radical signal did not decay to the signal background, indicating equilibrium between C 3 H 5 + NO and C 3 H 5 NO. This allowed the C 3 H 5 + NO ⇄ C 3 H 5 NO equilibrium to be studied and the equilibrium constants of the reaction between 414 and 500 K to be determined. With the standard second-and third-law analysis, the enthalpy and entropy of the C 3 H 5 + NO ⇄ C 3 H 5 NO reaction were obtained. Combined with the calculated standard entropy of reaction (ΔS°2 98 = 137.2 J mol −1 K −1 ), the third-law analysis resulted in ΔH°2 98 = 102.4 ± 3.2 kJ mol −1 for the C 3 H 5 −NO bond dissociation enthalpy. ■ INTRODUCTIONReactive hydrocarbon free radicals and nitrogen oxides (NO x = NO + NO 2 ) are produced in several common environments. Energy released by burning of hydrocarbons creates a variety of reactive intermediates, including unsaturated alkenyl radicals, and combustion under atmospheric conditions leads to the formation of nitrogen oxides. 1,2 Oxides of nitrogen are primary anthropogenic pollutants but also have natural sources in the atmosphere. 3,4 The principles governing mutual reactions of alkenyl radicals and NO x are important for the understanding of hydrocarbon oxidation mechanisms and optimization of combustion processes.Allyl radical (C 3 H 5 ) is the simplest conjugated, resonancestabilized alkenyl radical. Alkenyl radicals are formed in hydrogen abstraction reactions by reactive species (e.g., OH or other radicals) from carbon atoms at the β-position to the double bond in alkenes and by pyrolysis of larger hydrocarbons at elevated temperatures. 5−7 Small unsaturated hydrocarbon radicals with resonance-stabilized structures are thermodynamically more stable than similar saturated radicals lacking resonance stabilization. Consequently, they reach higher concentrations under combustion conditions and play a role in the molecular weight growth chemistry. They are identified as precursors for polycyclic aromatic hydrocarbons (PAHs) and, subsequently, for soot formation. 8−10 In the present work, two reactions of allyl radical with nitrogen oxides were investigated:(1)Both reactions have been stu...

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Flash photolysis studies of free-radical reactions: C3H5 + C3H5 (293-691 K) and C3H5 + NO (295-400 K)

Cited by 65 publications

References 1 publication

Kinetics of the reaction between H atoms and allyl radicals

Kinetics of the reaction between H atoms and allyl radicals

The reaction of allyl radicals with oxygen atoms—rate coefficient and product branching

Gas Phase Kinetics and Equilibrium of Allyl Radical Reactions with NO and NO₂

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Flash photolysis studies of free-radical reactions: C3H5 + C3H5 (293-691 K) and C3H5 + NO (295-400 K)

Cited by 65 publications

References 1 publication

Kinetics of the reaction between H atoms and allyl radicals

Kinetics of the reaction between H atoms and allyl radicals

The reaction of allyl radicals with oxygen atoms—rate coefficient and product branching

Gas Phase Kinetics and Equilibrium of Allyl Radical Reactions with NO and NO2

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Gas Phase Kinetics and Equilibrium of Allyl Radical Reactions with NO and NO₂