Energy of the O–NO2 bond dissociation and the mechanism of the gas-phase monomolecular decomposition of aliphatic alcohol nitroesters

Храпковский, Г. М.; Шамсутдинов, Т. Ф.; Чачков, Д. В.; Шамов, А. Г.

doi:10.1016/j.theochem.2004.09.001

Cited by 18 publications

(11 citation statements)

References 6 publications

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“…The obtained O–NO 2 bond dissociation energies (BDEs) are in good agreement with the most recent differential scanning calorimetry (DSC) measurement of 32.6 kcal/mol and with a range of previous experimental studies, 35.0, 39.5, , and 46.0 kcal/mol. The calculated O–N BDEs are also consistent with the reported previous computational values of 35.8, 37.7, 39.0, 39.2, and 39.9 kcal/mol, given the differences in the employed computational techniques. The estimated pre-exponential factors of ∼17 to 18 are in reasonable agreement with relevant experimental values of 14.9, 15.6 (PETN decomposition in melt and in a trotyl solution), 16.1 (PETN in 5% phthalate solution), and 19.8 s –1 (PETN in melt) .…”

Section: Modeling Chemical Reactionssupporting

confidence: 90%

Thermal Decomposition Mechanisms of Nitroesters: Ab Initio Modeling of Pentaerythritol Tetranitrate

2013

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The lack of fundamental understanding of the intricate interplay between large amounts of chemical energy stored in energetic molecular materials and their sensitivity to detonation initiation represents a stubborn outstanding challenge. This study sheds much needed light on the atomic decomposition mechanisms of nitroesters with an example of pentaerythritol tetranitrate (C5H8N4O12, also known as PETN), used as an explosive and a medication. The performed study is based on density functional theory combined with variational transition-state theory and large-scale massively parallel periodic supercell calculations and presents a detailed analysis of thermal initiation of chemical reactions and their kinetics in the gas-phase PETN molecules, the ideal bulk crystals, and on two low energy surfaces, (101) and (110). The obtained activation barriers, reaction energies, and reaction rates of simulated bond dissociation mechanisms reveal that the overall decomposition of condensed nitroesters is defined by the interplay of two major reactions, the fast endothermic O-NO2 homolysis and the slow exothermic HONO elimination. While the O–N cleavage has a low activation barrier and essentially initiates the degradation of the material, the HONO elimination pathway serves to accelerate the global process by generating heat to support the reaction. This trend is suggested to be general for a large class of traditional and novel nitroesters.

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Section: Modeling Chemical Reactionssupporting

confidence: 90%

Thermal Decomposition Mechanisms of Nitroesters: Ab Initio Modeling of Pentaerythritol Tetranitrate

2013

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“…This value is in good agreement with the ONO 2 bond dissociation energy of 38.5 kcal mol −1 in ethyl nitrate, calculated by Khrapkovskii et al using the density‐functional B3LYP method and is somewhat lower, although in agreement in the range of the quoted uncertainties, with BDE (ONO 2 ) = 41.1 ± 1.0 kcal mol −1 recommended by Luo .…”

Section: Resultssupporting

confidence: 90%

Kinetic and Mechanistic Study of the Thermal Decomposition of Ethyl Nitrate

Morin

Bedjanian

2017

Int. J. Chem. Kinet.

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Thermal decomposition of ethyl nitrate (ENT; CH3CH2ONO2) has been studied in a low‐pressure flow reactor combined with a quadrupole mass spectrometer. The rate constant of the nitrate decomposition was measured as a function of pressure (1–12.5 Torr of helium) and temperature in the range 464–673 K using two different approaches: from kinetics of ENT loss and those of the formation of the reaction product (CH3 radical). The fit of the observed falloff curves with two‐parameter expression k1=k0k∞[normalM]k0[normalM]+k∞×0.6(1+(prefixlog(k0[M]k∞))2)−1 provided the following low‐ and high‐pressure limits for the rate constant of ENT decomposition: k0 = 1.0 × 10−4 exp(−16,400/T) cm3 molecule−1 s−1 and k∞ = 1.08 × 1016 exp(−19,860/T) s−1, respectively, which allow to reproduce (via above expression and with 20% uncertainty) all the experimental data obtained for k1 in the temperature and pressure range of the study. It was observed that the initial step of the thermal decomposition of ethyl nitrate is O–NO2 bond cleavage leading to formation of NO2 and CH3CH2O radical, which rapidly decomposes to form CH3 and formaldehyde as final products. The yields of NO2, CH3, and formaldehyde upon decomposition of ethyl nitrate were measured to be near unity. In addition, the kinetic data were used to determine the O–NO2 bond dissociation energy in ENT: 38.3 ± 2.0 kcal mol−1.

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“…These values are in good agreement with the O-NO 2 bond dissociation energy of 38.3 and 38.2 kcal mol -1 in n-propyl and n-butyl nitrates, respectively, calculated by Khrapkovskii et al[29] using density-functional B3LYP method. Zeng et al[30] using different DFT methods calculated O-NO 2 bond dissociation energy in n-propyl nitrate in the range (34.1-42.2) kcal mol -1 , which overlaps the experimental value from this work.…”

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confidence: 88%