The solid phase thermal decomposition and nanocrystal effect of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) <i>via</i> ReaxFF large-scale molecular dynamics simulation

Zheng, Ke; Wen, Yushi; Huang, Bing; Wang, Jun; Chen, Jin; Xie, Gongnan; Lv, Guoqing; Liu, Jian; Qiao, Zhiqiang; Yang, Guangcheng

doi:10.1039/c9cp01482a

Cited by 22 publications

(16 citation statements)

References 42 publications

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“…On the basis of these mechanisms, we have proposed probable reaction channels in parts a and b of Figures that could occur after electronic excitation of RDX. In Figure a, we depict reactions channels that could initiate due to N–NO 2 fission, C–N bond rupture, and HONO-elimination at the ground state of RDX; these reactions have been previously proposed through theoretical calculations − ,, and certainly rationalize the products observed in our experiments.…”

Section: Resultssupporting

confidence: 76%

“…Over the past decades, copious studies have been devoted to investigate the fundamental chemical processes involved in the fragmentation of RDX (Scheme ). − Diverse methods ranging from shock waves, infrared (IR) lasers, electron beams to ultraviolet (UV) lasers have been employed to initiate the complex dissociation mechanism(s), but the very first reaction step(s) that initialize the decomposition is (are) still debated. ,− …”

Section: Introductionmentioning

confidence: 99%

“…Dose-dependent studies in conjunction with wavelength-dependent photolysis experiments aid in identifying key primary and secondary species as well as distinguish pathways that are preferred at higher and lower photon energies. Mechanisms based on previously reported gas-phase and condensed-phase calculations − ,,,, were exploited to propose the formation pathways of the observed products. Experimental results suggest that N–NO 2 bond fission and nitro–nitrite isomerization are the initial steps in the UV photolysis of RDX.…”

Section: Introductionmentioning

confidence: 99%

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Investigating the Photochemical Decomposition of Solid 1,3,5-Trinitro-1,3,5-triazinane (RDX)

et al. 2020

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Energetic materials such as 1,3,5-trinitro-1,3,5triazinane (RDX) are known to photodissociate when exposed to UV light. However, the fundamental photochemical process(es) that initiate the decomposition of RDX is (are) still debatable. In this study we investigate the photodissociation of solid-phase RDX at four distinct UV wavelengths (254 nm (4.88 eV), 236 nm (5.25 eV), 222 nm (5.58 eV), 206 nm (6.02 eV)) exploiting a surface science machine at 5 K. We also conducted dose-dependent studies at the highest and lowest photon energy of 206 nm (6.02 eV) and 254 nm (4.88 eV). The products were monitored online and in situ via infrared spectroscopy. During the temperatureprogrammed desorption phase, the subliming products were detected with a reflectron time-of-flight mass spectrometer coupled with soft-photoionization at 10.49 eV (PI-ReTOF-MS). Infrared spectroscopy revealed the formation of small molecules including nitrogen monoxide (NO), nitrogen monoxide dimer ([NO] 2 ), dinitrogen trioxide (N 2 O 3 ), carbon dioxide (CO 2 ), carbon monoxide (CO), dinitrogen monoxide (N 2 O), water (H 2 O), and nitrite group (−ONO) while ReTOF-MS identified 32 cyclic and acyclic products. Among these, 11 products such as nitryl isocyanate (CN 2 O 3 ), 5-nitro-1,3,5-triazinan-2-one (C 3 H 6 N 4 O 3 ) and 1,5-dinitro-1,3,5-triazinan-2-one (C 3 H 5 N 5 O 5 ) were detected for the first time in photodecomposition of RDX. Dose-dependent in combination with wavelength-dependent photolysis experiments aid to identify key primary and secondary products as well as distinguished pathways that are more preferred at lower and higher photon energies. Our experiments reveled that N−NO 2 bond fission and nitro−nitrite isomerization are the initial steps in the UV photolysis of RDX. Reaction mechanisms are derived by comparing the experimental findings with previous electronic structure calculations to rationalize the origin of the observed products. The present study can assist in understanding the complex chemistry behind the photodissociation of electronically excited RDX molecule, thus bringing us closer to unraveling the decomposition mechanisms of nitramine-based explosives.

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Section: Resultssupporting

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigating the Photochemical Decomposition of Solid 1,3,5-Trinitro-1,3,5-triazinane (RDX)

et al. 2020

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“…Recently, RMD was also used to simulate the thermal decomposition process of nano-explosives which contain C, H, O and N elements. Zheng et al [25] used the RMD to simulate the whole thermal decomposition process of nanocrystalline RDX. It demonstrated a promising energy distribution mechanism transfer for nanostructure with the information for understanding the effect of the size of nanoparticles on the chemical kinetics of thermal decomposition and reaction growth.…”

Section: Introductionmentioning

confidence: 99%

Atomistic Insight into Thermal Decomposition of 1,3,5‐Triamino‐2,4,6‐trinitrobenzene Nanoparticles According to the ReaxFF Molecular Dynamics Method

2022

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As a widely used wood explosive, 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) and its nanoparticles are insensitive due to the graphene-like structure. In this paper, the decomposition processes of TATB and its nanospheres with different radius (30, 40, 50, 60, and 70 Å) at 2000 K and 3000 K are calculated by the reactive molecular dynamic simulations. The initial reactions and the evolution of clusters (whose molecular weight is larger than TATB) are analyzed. The results show that there are four major distinctive channels for the initial decomposition of 30 Å nano-TATB system: (1) the formation of HO fragment; (2) the C-NO 2 bond breaking to form NO 2 ; (3) conversion of nitro to nitroso; (4) hydrogen transfer. For the main production gases, the amount of CO 2 , N 2 and H 2 O will increase with the increase of temperature and the amount of H 2 O at 3000 K is obviously more than that at 2000 K accordingly to conventional TATB. This demonstrates that high temperature is beneficial to the pyrolysis of conventional TATB. In contrast to the results of TATB, the total amount of gas molecules of nanoparticles decreases, indicating that high temperature is not conducive to the pyrolysis reaction of nano-TATB. The results shed light on the complicated interplay between morphological evolution and external conditions. It provides insights into the thermal decomposition mechanism of TATB and its nanoparticles at the atomic level.

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“…It has been reported that many nanosized metals (Al, Mg, B, W, Zr, Ni, Cu, Fe, Ag, and Co) and metal oxides (e.g., Pb-, Cu-, Bi-, and Fe-based oxides) are widely used in solid propellants as fuels and the burning rate catalysts. , For instance, the nano-CuO and nano-Fe 2 O 3 have better catalytic effects than the microsized ones, , whereas the nano-Al can not only increase the energy content, but also enhance the burn rate of propellants with reduced pressure exponent under high pressure ranges . Furthermore, the thermal decomposition is the initial stage of combustion and explosion of materials, and the performance of thermal decomposition is an essential index that determines the combustion and explosion of materials. − Therefore, the thermal behaviors and decomposition mechanisms of ICM-102 under the effects of nanosized metals and metal oxides must be investigated before the ICM-102 is applied in propellants. In this work, the thermal decompositions of ICM-102 and ICM-102 composites (with Al, Co, Mg, Si, Ti, Zr, CuO, and Fe 2 O 3 ) were investigated by thermogravimetric analysis and differential scanning calorimetry (TGA-DSC) technique.…”

Section: Introductionmentioning

confidence: 99%

Effects of Nanosized Metals and Metal Oxides on the Thermal Behaviors of Insensitive High Energetic Compound ICM-102

Gao

Chen

et al. 2019

J. Phys. Chem. C

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In this paper, the composites of a newly insensitive high explosive 2,4,6-triamino-5-nitropyrimidine-1,3-dioxide (ICM-102) with nanosized metals (Al, Co, Mg, Si, Ti, and Zr) and nanosized metal oxides (CuO and Fe2O3) have been prepared and investigated in terms of thermal reactivity. The catalytic effects on the thermal decomposition of ICM-102 composites have been investigated by TGA-DSC technique. Among all the composites, ICM-102/Co shows the minimum residue rate of 1.57 wt % and ICM-102/Si shows the maximum heat release of 1001.9 J g–1. The kinetic parameters for the catalytic decomposition of ICM-102 have been obtained. The activation energy (E a ) of ICM-102 decomposition is within 197.9–212.0 kJ mol–1. Compared with ICM-102, the E a of ICM-102/Si decomposition was decreased by about 90 kJ mol–1. The decomposition gaseous products of ICM-102 and its composites have been analyzed by the TG-MS technique. It has been shown that the main gaseous products are H2O, C2H4, C3, and C2N or C3H2. The ICM-102 decomposition undergoes intramolecular dehydration, followed by two different ring-opening chemical pathways. The decomposition products are largely dependent on the type of additives.

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The solid phase thermal decomposition and nanocrystal effect of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) via ReaxFF large-scale molecular dynamics simulation

Abstract: The solid phase thermal decomposition and nanocrystal effect are extremely important to understand the ignition, combustion, reaction growth and buildup to detonation under shock wave action.

Cited by 22 publications

References 42 publications

Investigating the Photochemical Decomposition of Solid 1,3,5-Trinitro-1,3,5-triazinane (RDX)

Investigating the Photochemical Decomposition of Solid 1,3,5-Trinitro-1,3,5-triazinane (RDX)

Atomistic Insight into Thermal Decomposition of 1,3,5‐Triamino‐2,4,6‐trinitrobenzene Nanoparticles According to the ReaxFF Molecular Dynamics Method

Effects of Nanosized Metals and Metal Oxides on the Thermal Behaviors of Insensitive High Energetic Compound ICM-102

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