Measurement of product branching ratios of the cyanato + nitric oxide reaction

Cooper, William F.; Hershberger, John F.

doi:10.1021/j100181a046

Cited by 78 publications

(70 citation statements)

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“…The calculated bond-breaking barrier was 8.23 kcal/mol (TS 11-P3 ). However, the 1,2 H-shift from 8 may form a very stable conformer, 10, 30.72 kcal/mol lower than the reactants, and the barrier for this transfer was 46.93 kcal/mol, TS [8][9][10] . From our calculation it seemed unlikely to proceed further from 10 to produce P3 or P4, since it needed to form 12 or 13 first.…”

Section: Table 2: Ground State Electronic Energies (Au) and The Relatmentioning

confidence: 96%

Theoretical Study of Reaction Mechanisms for NCX (X = O, S) + C₂H₂

Chen

2003

J. Phys. Chem. A

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The reaction mechanisms for NCX (X ) O, S) with C 2 H 2 was studied theoretically. The possible reaction mechanisms of NCO + C 2 H 2 investigated in this study were categorized into five different pathways leading to the five possible final products: HCCO + HCN, HCCO + HNC, HNCO + C 2 H, HONC + C 2 H, and HC 2 NCO + H, labeled in order from P1 to P5, respectively. Similar calculations were also carried out for the NCS counterpart, and the energy barriers as well as the products were compared. Direct hydrogen abstraction is favored in the formation of HNCO instead of HOCN. In contrast, it is much easier to form HSCN rather than HNCS. There are two different paths for the oxazole/thiazole formation as an intermediate, and the order of energy barriers of these two paths is opposite in NCO and NCS. The product channel of HNCO/ HSCN + C 2 H may be kinetically favored at higher temperature. Other product channels are consistent with the experimental prediction of the formation of initial short-lifetime NCO/NCS-C 2 H 2 adducts which then undergo rapid transformation into the products.

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Section: Table 2: Ground State Electronic Energies (Au) and The Relatmentioning

confidence: 96%

Theoretical Study of Reaction Mechanisms for NCX (X = O, S) + C₂H₂

Chen

2003

J. Phys. Chem. A

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“…[c0(u'3120@r = @dt[CNIO,Br (14 The initial concentration [CN]O,B~ of the C N radical used in eq IC is given by the following expression where US, is the absorption cross section of BrCN at 193 nm, ,$er is the laser illuminance used for the photolysis of BrCN, p~~ is the density of BrCN, and +er is the quantum yield for the production of C N from BrCN a t 193 nm. Substitution of this expression for [CN]O,B~ from eq 11 into eq IC and defining @dt = @to&",Br, where @tot = gives eq Id.…”

mentioning

confidence: 99%

On the mechanism and branching ratio of the cyanogen + oxygen .fwdarw. carbon monoxide + nitric oxide reaction channel using transient IR emission spectroscopy

Mohammad¹,

Morris²,

Fink³

et al. 1993

J. Phys. Chem.

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The contribution of the title reaction to the total reaction of CN + 0 2 has been determined, using time-resolved IR emission spectroscopy of the product CO(u"). This product channel is found to contribute up to 29% with 2% experimental variance to the total reaction. A contribution of this magnitude to the total reaction of CN + 0 2 by this product channel proceeding via a four-center transition state is energetically improbable. A b initio calculations have been performed on two-and four-center transition states which are presumably formed in the reaction between CN radicals and molecular oxygen. The results of these calculations confirm the existence of a very high barrier to the formation of a four-center transition state. Consequently, a new mechanism for the formation of CO in reaction 1 is proposed. This new mechanism consists of two sequential steps rather than two parallel steps to explain the formation of the products NCO, 0, and CO in the reaction CN + 0 2 .

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“…Since we probe only the ground vibrational state, the nascent vibrational distribution must be relaxed to a Boltzmann distribution in order for the molecular number densities to be reliably measured. SF 6 has previously been shown to be an efficient relaxer of vibrational excitation for N 2 O and CO 2 [14][15][16], and probably also relaxes HCNO as well. Under the experimental conditions of 1.0 Torr of SF 6 , this relaxation still takes about 50 sec for N 2 O and CO 2 , but is essentially complete on a timescale short compared to the slow decay, which is attributed to diffusion of molecules out of the probed volume.…”

Section: Product Branching Ratiosmentioning

confidence: 99%

Kinetics of HCCl + NO_x reactions

Baren

Erickson

Hershberger

2001

Int J of Chemical Kinetics

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The kinetics of reactions of HCCl with NO and NO 2 were investigated over the temperature ranges 298-572 k and 298-476 k, respectively, using laser-induced fluorescence spectroscopy to measure total rate constants and time-resolved infrared diode laser absorption spectroscopy to probe reaction products. Both reactions are fast, with k(HCCl + NO) = (2.75 ± 0.2) × 10 −11 cm 3 molecule −1 s −1 and k(HCCl + NO 2 ) = (1.10 ± 0.2) × 10 −10 cm 3 molecule −1 s −1 at 296 K. Both rate constants displayed only a slight temperature dependence. Detection of products in the HCCl + NO reaction at 296 K indicates that HCNO + Cl is the major product with a branching ratio of φ = 0.68 ± 0.06, and NCO + HCl is a minor channel with φ = 0.24 ± 0

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Measurement of product branching ratios of the cyanato + nitric oxide reaction

Cited by 78 publications

References 4 publications

Theoretical Study of Reaction Mechanisms for NCX (X = O, S) + C₂H₂

Theoretical Study of Reaction Mechanisms for NCX (X = O, S) + C₂H₂

On the mechanism and branching ratio of the cyanogen + oxygen .fwdarw. carbon monoxide + nitric oxide reaction channel using transient IR emission spectroscopy

Kinetics of HCCl + NO_x reactions

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Measurement of product branching ratios of the cyanato + nitric oxide reaction

Cited by 78 publications

References 4 publications

Theoretical Study of Reaction Mechanisms for NCX (X = O, S) + C2H2

Theoretical Study of Reaction Mechanisms for NCX (X = O, S) + C2H2

On the mechanism and branching ratio of the cyanogen + oxygen .fwdarw. carbon monoxide + nitric oxide reaction channel using transient IR emission spectroscopy

Kinetics of HCCl + NOx reactions

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Theoretical Study of Reaction Mechanisms for NCX (X = O, S) + C₂H₂

Theoretical Study of Reaction Mechanisms for NCX (X = O, S) + C₂H₂

Kinetics of HCCl + NO_x reactions