Kinetics of fast reactions in condensed systems: Some recent results (an autoreview)

Shteĭnberg, A. S.; Берлин, А. А.; Denisaev, A. A.; Mukasyan, Alexander S.

doi:10.3103/s1061386211040030

Cited by 8 publications

(6 citation statements)

References 12 publications

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“…Additionally, diaminocarbene [C(NH 2 ) 2 ] was a major precursor toward many products by providing the cyano species (CN, HCN, and HNC) along with an amino radical (NH 2 ). Future experiments exploiting isotopically labeled FOX-7, such as 13 C-FOX-7, could lend mass spectrometric support to the assignment of the molecular formulas of larger molecules through isotope shifts in the QMS and PI-ReTOF-MS data. Once accomplished, experiments utilizing tunable PI can provide further selections of the remaining isomers using experimental or calculated IEs.…”

Section: Discussionmentioning

confidence: 99%

“…An understanding of the stability, , explosion efficiency, , and shock/thermal sensitivity of energetic materials such as FOX-7 (1,1-diamino-2,2-dinitroethylene) (Scheme ) is critical to access the potential of novel compounds as safe and effective energetic materials. − Investigations into the decomposition mechanisms of FOX-7 and the subsequent reactions of newly generated radical species are challenging due to the non-equilibrium conditions of these reactions that result in excess kinetic and internal energy capable of overcoming reaction entrance barriers . Traditional explosives such as RDX (1,3,5-trinitro-1,3,5-triazane) and HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine), as well as the explosives of interest octanitrocubane and CL-20 (hexanitrohexaazaisowurtzitane), , all possess cyclic structures with nitro moieties (−NO 2 ), while FOX-7 is an acyclic molecule that also contains amino groups (NH 2 ) that provide more complex decomposition pathways.…”

Section: Introductionmentioning

confidence: 99%

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Electron-Induced Decomposition of Solid 1,1-Diamino-2,2-dinitroethylene (FOX-7) at Cryogenic Temperatures

et al. 2023

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Solid FOX-7 (1,1-diamino-2,2-dinitroethylene), an energetic material of interest due to its high stability and low shock/thermal sensitivity, was exposed to energetic electrons at 5 K to explore the fundamental mechanisms leading to decomposition products and provide a better understanding of the reaction pathways involved. As a result of the radiation exposure, infrared spectroscopy revealed carbon dioxide (CO2) and carbon monoxide (CO) trapped in the FOX-7 matrix, while these compounds along with water (H2O), nitrogen monoxide (NO), and cyanogen (C2N2) were detected exploiting quadrupole mass spectrometry both during irradiation and during the warming phase from 5 to 300 K. Photoionization reflectron time-of-flight mass spectrometry detected small molecules such as ammonia (NH3), nitrogen monoxide (NO), and nitrogen dioxide (NO2) as well as more complex molecules up to 96 amu. Potential reaction pathways are presented and assignments are discussed. Among the reaction mechanisms, the importance of an initial nitro-to-nitrite isomerization is highlighted by the observed decomposition products.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electron-Induced Decomposition of Solid 1,1-Diamino-2,2-dinitroethylene (FOX-7) at Cryogenic Temperatures

et al. 2023

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“…An intimate understanding of the reaction mechanisms involved in the decomposition of molecular energetic materials such as the nitro-amine FOX-7 (1,1-diamino-2,2-dinitroethylene; Scheme ) and of the successive reactions of the radical fragments produced in these processes is imperative to predict the long-term stability (aging behavior), , explosion efficiency (performance), , and the sensitivity to heat and shock of energetic materials. − These insights are further invaluable to dispose of energetic materials safely under controlled conditions, to model the time dependence during the ignition stage of explosives, and to develop novel insensitive energetic materials . The investigation of these processes along with the consecutive reactions of the transient radicals represents a fundamental challenge for experimentalists, theoreticians, and modelers considering the nonequilibrium conditions under which these reactions often occur, as radicals can be born with excess kinetic and internal, i.e., rovibrational, energy and in excited electronic states . This excess energy results in nonthermal equilibrium conditions so that entrance barriers (or classical activation energies) can be overcome .…”

Section: Introductionmentioning

confidence: 99%

“…12 The investigation of these processes along with the consecutive reactions of the transient radicals represents a fundamental challenge for experimentalists, theoreticians, and modelers 13 considering the nonequilibrium conditions under which these reactions often occur, as radicals can be born with excess kinetic and internal, i.e., rovibrational, energy and in excited electronic states. 14 This excess energy results in nonthermal equilibrium conditions so that entrance barriers (or classical activation energies) can be overcome. 15 The decomposition of nitroamine-based molecular energetic materials is very complex.…”

Section: Introductionmentioning

confidence: 99%

Exploring the Photochemistry of Solid 1,1-Diamino-2,2-dinitroethylene (FOX-7) Spanning Simple Bond Ruptures, Nitro-to-Nitrite Isomerization, and Nonadiabatic Dynamics

et al. 2022

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The UV photolysis of solid FOX-7 at 5 K with 355 and 532 nm photons was investigated to unravel initial isomerization and decomposition pathways. Isomer-selective single photon ionization coupled with reflectron time-of-flight mass spectrometry (ReTOF-MS) documented the nitric oxide (NO) loss channel at 355 nm along with a nitro-to-nitrite isomerization, which was observed by using infrared spectroscopy, representing the initial reaction pathway followed by O�NO bond rupture of the nitrite moiety. A residual gas analyzer detected molecular oxygen for the 355 and 532 nm photolysis at a ratio of 4.3 ± 0.3:1, which signifies FOX-7 as an energetic material that provides its own oxidant once the decomposition starts. Overall branching ratios for molecular oxygen versus nitric oxide were derived to be 700 ± 100:1 at 355 nm. It is notable that this is the first time that molecular oxygen was detected as a decomposition product of FOX-7. Computations show that atomic oxygen, which later combines to form molecular oxygen, is likely released from a nitro group involving conical intersections. The condensed phase potential energy profile computed at the CCSD(T) and CASPT2 level correlates well with the experiments and highlights the critical roles of conical intersections, nonadiabatic dynamics, and the encapsulated environment that dictate the mechanism of the reaction through intermolecular hydrogen bonds.

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“…Chemical reaction in a compressed porous multicomponent mixture is described by a phenomenological model of irreversible chemical transformations P based on zero-order kinetics [19][20][21][22][23] …”

Section: Mathematical Description Of Multicomponent Media Behaviour Amentioning

confidence: 99%

Destruction of cylindrical ampoules containing solid phase reaction mixtures under explosive loading

Зелепугин¹,

Иванова²,

Yunoshev³

et al. 2015

LoM

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Peculiarities of solid-phase synthesis in aluminum-sulfur and aluminum-fluoroplast mixtures in cylinder ampoules under explosive loading have been studied in experiments and numerically. In experiments the chosen parameters of explosive loading were similar to those which are usually used for explosive compacting of the inert porous materials in cylinder ampoules. The results of experiments show that cylinder ampoules are destructed in explosive loading conditions when mixture used as a filler is capable of very fast exothermal reactions. To find out the reasons of ampoules destruction numeric calculations have been carried out by the method of finite elements on the base of multicomponent media. While studying the deformation of multicomponent media it is necessary to take into account the state and reaction of each component and components displacement inside a chosen released volume of the mixture. As a condition of compatible deformation of the components a pressure balance of mixture components was chosen. Synthesis reaction in the mixture was described by the phenomenological model of irreversible chemical transformations based on zero-order kinetics. Simulation of compaction of the porous mixture was carried out on the base of a kinetic model of active type, which describes the growth or collapse of the pores resulting in a permanent change of the material properties and stress relaxation. It was found that pressure is increased sharply at the bottom of the ampoule when shock wave is reflected from the bottom ampoule lid as a compressive wave which is followed by chemical transformation rate growth. High rate of heat release during reaction in a lower ampoule part resulted in gas phase formation which leads to a further pressure increase and becomes the reason of ampoules destruction.

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Kinetics of fast reactions in condensed systems: Some recent results (an autoreview)

Cited by 8 publications

References 12 publications

Electron-Induced Decomposition of Solid 1,1-Diamino-2,2-dinitroethylene (FOX-7) at Cryogenic Temperatures

Electron-Induced Decomposition of Solid 1,1-Diamino-2,2-dinitroethylene (FOX-7) at Cryogenic Temperatures

Exploring the Photochemistry of Solid 1,1-Diamino-2,2-dinitroethylene (FOX-7) Spanning Simple Bond Ruptures, Nitro-to-Nitrite Isomerization, and Nonadiabatic Dynamics

Destruction of cylindrical ampoules containing solid phase reaction mixtures under explosive loading

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