Thermal explosion times of nitromethane, perdeuteronitromethane, and six dinitroalkanes as a function of temperature at static high pressures of 1–50 kbar☆

Shaw, Robert; DeCarli, Paul S.; Ross, David S.; Lee, E.L.; Stromberg, H. D.

doi:10.1016/0010-2180(79)90029-4

Cited by 27 publications

(21 citation statements)

References 9 publications

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“…68 -70 It has not escaped our attention that the prediction of a C-H bond high-stretching here suggests that a proton abstraction may be indeed involved in the first activation step, thus reducing the observed time to selfexplosion under high pressure. 68 This type of proton dissociation has a long history in high pressure studies. While our prediction is not rigorous, the reasoning that implies it warrants some attention; we believe that more theoretical work is needed in this direction.…”

Section: Discussionmentioning

confidence: 99%

“…68 -70 Most of these studies are concerned with the nature of chemical products that may speed up detonation. Shaw et al, 68 ments indicated that a reaction involving hydrogen atoms or protons is involved in the first steps of this fast-reaction process. This suggestion was later corroborated by Blais et al 69 by more direct measurements, who also referred to a sequence of previous investigations by Engelke and others.…”

Section: C-h Bond High Stretching Under Uniaxial Compressionmentioning

confidence: 99%

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Electronic structure of solid nitromethane: Effects of high pressure and molecular vacancies

Margetis

Kaxiras

Elstner

et al. 2002

The Journal of Chemical Physics

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The combined effect of pressure and molecular vacancies on the atomic structure and electronic properties of solid nitromethane, a prototypical energetic material, is studied at zero temperature. The self-consistent charge density-functional tight-binding method is applied in order to investigate changes induced in the band gap of this system by uniform and uniaxial strain of up to 70%, corresponding to static pressure in the range of up to 200 GPa. The effects of molecular vacancies with densities ranging from 3% to 25% have also been considered. A surprising finding is that uniaxial compression of about 25–40 GPa along the b lattice vector causes the C–H bond to be highly stretched and leads to proton dissociation. This event also occurs under isotropic compression but at much higher pressure, being indicative of a detonation chemistry which is preferential to the pressure anisotropy. We also find that the band gap, although evidently dependent on the applied strain, crystal anisotropy and vacancy density, is not reduced considerably for electronic excitations to be dominant, in agreement with other recent first-principles studies.

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Section: Discussionmentioning

confidence: 99%

Section: C-h Bond High Stretching Under Uniaxial Compressionmentioning

confidence: 99%

Electronic structure of solid nitromethane: Effects of high pressure and molecular vacancies

Margetis

Kaxiras

Elstner

et al. 2002

The Journal of Chemical Physics

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“…͑i͒ The formation of the aci-ion (CH 3 NO 2 →CH 2 NO 2 Ϫ ϩH ϩ ), taking into account that nitromethane-h 3 behaves like a weak acid (p ka Ϸ10), 32 has been developed by Engelke. 33,20 ͑ii͒ The isomerisation of nitromethane to methyl nitrite (CH 3 NO 2 →CH 3 ONO) has been suggested to be an initial important step for triggering the detonation of liquid nitromethane. 34,35 However no appearance of a new mode in the C-O region (ϳ700 cm Ϫ1 ) takes place.…”

Section: Discussionmentioning

confidence: 99%

“…However there is not a general consensus among researchers working on the chemical relationship between the chemical kinetics that occur in detonic materials and their chemical structure. 20,21 It seems reasonable to expect that the NO 2 group plays a fundamental role in the decomposition mechanism initiation under shock, at least in aliphatic nitro compounds. A recent study by time resolved Raman spectroscopy of nitromethane-h 3 under shock up to 14 GPa ͑Refs.…”

Section: Introductionmentioning

confidence: 99%

Comparative Raman spectroscopy of nitromethane-h3, nitromethane-d3, and nitroethane up to 20 GPa

Courtecuisse

Cansell

Fabre³

et al. 1998

The Journal of Chemical Physics

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Articles you may be interested in[N(CH3)3H]2ZnCl4: Ferroelectric properties and characterization of phase transitions by Raman spectroscopy Nitromethane has been studied as a model of energetic alphatic nitro compounds. The initiation of the decomposition mechanism of nitromethane in the vicinity of its explosive decomposition pressure conditions has been studied under high static pressure at ambient temperature by Raman spectroscopy. The vibrational modes a (NO 2 ) and, to a lesser degree, s (NO 2 ) show a specific behavior at the solid ͑II͒-solid ͑III͒ 7.5 GPa transition ͑at ambient temperature͒. A comparison of the Raman spectrum of nitromethane-h 3 with new high pressure Raman spectroscopic results for nitromethane-d 3 and nitroethane allows one to characterize the physico chemical behavior of these three compounds in relation to their detonic properties.

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“…In this work, we adopt the pre-exponential factor proposed by Hardesty [14] and adjust the activation temperature to T A = 11,350 K to match the experimentally calculated overtake time and the shape of the velocity versus distance graph of the shock-induced ignition experiment in Sheffield et al [17] (neat nitromethane, shocked at 9.1 GPa). It should be noted that even though the single-step Arrhenius rate equation is a good starting point for investigating general trends associated with hot spot ignition and burn [18], care should be taken with regard to its pressure validity regime, as suggested (for pressures of 0.1-5GPa) by Shaw et al [19]. In this work, the parameters have been calibrated and validated for the range of pressures arising in the problem at hand, but adjustment might be needed if other regimes are considered.…”

Section: Reaction Rates For Nitromethanementioning

confidence: 99%

The evolution of the temperature field during cavity collapse in liquid nitromethane. Part II: reactive case

Michael

Nikiforakis

2018

Shock Waves

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This work is concerned with the effect of cavity collapse in non-ideal explosives as a means of controlling their sensitivity. The main objective is to understand the origin of localised temperature peaks (hot spots) which play a leading order role at the early stages of ignition. To this end, we perform two-and three-dimensional numerical simulations of shock-induced single gas-cavity collapse in liquid nitromethane. Ignition is the result of a complex interplay between fluid dynamics and exothermic chemical reaction.In the first part of this work, we focused on the hydrodynamic effects in the collapse process by switching off the reaction terms in the mathematical formulation. In this part, we reinstate the reactive terms and study the collapse of the cavity in the presence of chemical reactions. By using a multi-phase formulation which overcomes current challenges of cavity collapse modelling in reactive media, we account for the large density difference across the material interface without generating spurious temperature peaks, thus allowing the use of a temperature-based reaction rate law. The mathematical and physical models are validated against experimental and analytic data. In Part I, we demonstrated that, compared to experiments, the generated hot spots have a more complex topological structure and that additional hot spots arise in regions away from the cavity centreline. Here, we extend this by identifying which of the previously determined hightemperature regions in fact lead to ignition and comment on the reactive strength and reaction growth rate in the distinct hot spots. We demonstrate and quantify the sensitisation of nitromethane by the collapse of the isolated cavity by comparing the ignition times of nitromethane due to cavity collapse and the ignition time of the neat material. The ignition in both the centreline hot spots and the hot spots generated by Mach stems occurs in less than half the ignition time of the neat material. We compare two-and three-dimensional simulations to examine the change in topology, temperatures, and reactive strength of the hot spots by the third dimension. It is apparent that belated ignition times can be avoided by the use of three-dimensional simulations. The effect of the chemical reactions on the topology and strength of the hot spots in the timescales considered is also studied, in a comparison between inert and reactive simulations where maximum temperature fields and their growth rates are examined.

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Thermal explosion times of nitromethane, perdeuteronitromethane, and six dinitroalkanes as a function of temperature at static high pressures of 1–50 kbar☆

Cited by 27 publications

References 9 publications

Electronic structure of solid nitromethane: Effects of high pressure and molecular vacancies

Electronic structure of solid nitromethane: Effects of high pressure and molecular vacancies

Comparative Raman spectroscopy of nitromethane-h3, nitromethane-d3, and nitroethane up to 20 GPa

The evolution of the temperature field during cavity collapse in liquid nitromethane. Part II: reactive case

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