Kinetics of the Gas-Phase Addition of the Ethyl Radical and the <i>tert</i>-Butyl Radical to NO

Dilger, Herbert; Stolmár, Martina; Himmer, Ulrich; Roduner, Emil; Reid, I. D.

doi:10.1021/jp981101a

Cited by 8 publications

(7 citation statements)

References 34 publications

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“…No rate constant could be found in the literature for the reaction of a bridgehead radical with NO but previous studies of reactions of carboncentred radicals with NO have been reported and represent an interesting comparison. The rate constant for the reaction of tertbutyl with NO determined by the muon spin relaxation technique is 1.0 ± 0.3 × 10 −11 cm 3 molecule −1 s −1 and that for ethyl radical is 2.2 ± 0.6 × 10 −11 cm 3 molecule −1 s −1 at 307 K. 38 A value of 3.5 ± 0.1 × 10 −11 cm 3 molecule −1 s −1 was measured by colour centre laser kinetic spectroscopy for the reaction of ethynyl radical with NO 39 and 9.5 ± 1.2 × 10 −12 cm 3 molecule −1 s −1 for benzyl radical with NO at 298 K by laser flash photolysis. 40 Our value compares favourably with these, with a rate constant ca.…”

Section: Methodsmentioning

confidence: 87%

Investigation of the gas phase reactivity of the 1-adamantyl radical using a distonic radical anion approach

Harman

Blanksby

2007

Org. Biomol. Chem.

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The gas phase reactions of the bridgehead 3-carboxylato-1-adamantyl radical anion were observed with a series of neutral reagents using a modified electrospray ionisation linear ion trap mass spectrometer. This distonic radical anion was observed to undergo processes suggestive of radical reactivity including radicalradical combination reactions, substitution reactions and addition to carbon-carbon double bonds. The rate constants for reactions of the 3-carboxylato-1-adamantyl radical anion with the following reagents were measured (in units 10 12 cm3 molecule 1 s 1): 18O2 (85±4), NO (38.4±0.4), I2 (50±50), Br2 (8±2), CH3SSCH3 (12±2), styrene (1.20±0.03), CHCl3 (H abstraction 0.41±0.06, Cl abstraction 0.65±0.1), CDCl3 (D abstraction 0.035±0.01, Cl abstraction 0.723±0.005), allyl bromide (Br abstraction 0.53±0.04, allylation 0.25±0.01). Collision rates were calculated and reaction efficiencies are also reported. This study represents the first quantitative measurement of the gas phase reactivity of a bridgehead radical and suggests that distonic radical anions are good models for the study of their elusive uncharged analogues. SummaryThe gas phase reactions of the bridgehead 3-carboxylato-1-adamantyl radical anion were observed with a series of neutral reagents using a modified electrospray ionisation linear ion trap mass spectrometer. This distonic radical anion was observed to undergo processes suggestive of radical reactivity including radical-radical combination reactions, substitution reactions and addition to carbon-carbon double bonds. The rate constants for reactions of the 3-carboxylato-1-adamantyl radical anion with the following reagents were measured (in units 10

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Section: Methodsmentioning

confidence: 87%

Investigation of the gas phase reactivity of the 1-adamantyl radical using a distonic radical anion approach

Harman

Blanksby

2007

Org. Biomol. Chem.

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“…20 The reaction kinetics of tert-butyl have been studied in the condensed phase [21][22][23] and the gas phase. 11,[24][25][26][27][28][29][30] The unimolecular decay of tert-butyl is of particular relevance to this work as a reference point for ground state dissociation dynamics. Knyazev et al 26 determined the rate constant for thermal decomposition of tert-butyl from 712-779 K using photoionization mass spectrometry.…”

Section: Introductionmentioning

confidence: 99%

Photodissociation dynamics of the tert-butyl radical via photofragment translational spectroscopy at 248 nm

Negru

Just

Park

et al. 2011

Phys. Chem. Chem. Phys.

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The photodissociation dynamics of the tert-butyl radical (t-C(4)H(9)) were investigated using photofragment translational spectroscopy. The tert-butyl radical was produced from flash pyrolysis of azo-tert-butane and dissociated at 248 nm. Two distinct channels of approximately equal importance were identified: dissociation to H + 2-methylpropene, and CH(3) + dimethylcarbene. Neither the translational energy distributions that describe these two channels nor the product branching ratio are consistent with statistical dissociation on the ground state, and instead favor a mechanism taking place on excited state surfaces.

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“…In most studies of this nature, muonium exhibits a primary KIE, but the Mu atom has also been used as a passive spectator in kinetic studies of radical reactions where the bond to Mu remained intact and where any secondary KIE was undetectable, within error. Such work includes the determination of accurate and absolute rate constants of radical clock reactions such as cyclization and ring fission in the liquid phase and of Mu−ethyl radical addition reactions to O 2 and NO. , …”

Section: Introductionmentioning

confidence: 99%

Kinetic Isotope Effect in the Gas-Phase Reaction of Muonium with Molecular Oxygen

Himmer¹,

Dilger²,

Roduner³

et al. 1999

J. Phys. Chem. A

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The rate constant of the gas-phase addition reaction of the light hydrogen isotope muonium to molecular oxygen, Mu + O2 → MuO2, was measured over a range of temperatures from 115 to 463 K at a pressure of 2 bar and from 16 to 301 bar at room temperature, using N2 as the moderator gas. The reaction remains in the termolecular regime over the entire pressure range. At room temperature, the average low-pressure limiting rate constant is k ch 0(Mu) = (8.0 ± 2.1) × 10-33 cm6 s-1, a factor of almost 7 below the corresponding rate constant for the H + O2 addition reaction, k ch 0(H). In contrast to k ch 0(H), which exhibits a clear negative temperature dependence, k ch 0(Mu) is essentially temperature independent. At room temperature, the kinetic isotope effect (KIE) is strongly pressure (density) dependent and is reversed at pressures near 300 bar. The kinetics are analyzed based on the statistical adiabatic channel model of Troe using a Morse potential, which works well in reproducing the overall KIE. The major factors governing the isotope effect are differences in the moment of inertia and density of vibrational states of the addition complex.

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Kinetics of the Gas-Phase Addition of the Ethyl Radical and the tert-Butyl Radical to NO

Cited by 8 publications

References 34 publications

Investigation of the gas phase reactivity of the 1-adamantyl radical using a distonic radical anion approach

Investigation of the gas phase reactivity of the 1-adamantyl radical using a distonic radical anion approach

Photodissociation dynamics of the tert-butyl radical via photofragment translational spectroscopy at 248 nm

Kinetic Isotope Effect in the Gas-Phase Reaction of Muonium with Molecular Oxygen

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