Infrared and Raman Spectra of 1,3,5-Trinitro-1,3,5-Triazacyclohexane (RDX)

Iqbal, Zafar; Suryanarayanan, K.; Bulusu, Suryanarayana; Autera, Joseph R.

doi:10.21236/ad0752899

Cited by 16 publications

(11 citation statements)

References 1 publication

(1 reference statement)

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“…Prominent vibrational features of the RDX are observed in the spectral regions of 3100−3000 cm −1 and 1600−600 cm −1 ; which are in excellent agreement with the IR spectrum of RDX reported in the literature (Table 4). 60,61 The amorphous nature of the RDX-film used in the present study is evident from broad and diffuse infrared absorptions measured before the irradiation (Figure S4b). The crystalline phase of RDX-film displays sharp vibrational bands with narrow bandwidth (Figure S4a).…”

Section: Resultsmentioning

confidence: 86%

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: Resultsmentioning

confidence: 86%

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

et al. 2020

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“…Condensed-phase mid-IR spectra of TNT, RDX, PETN, and a wide range of other explosives, boosters, primers, propellants, incendiaries, and related materials have been available for many years (61)(62)(63). Near-IR spectra of several of these species have also been measured between 1.0 and 2.3 µm using a scanning acousto-optic tunable filter spectrometer (64,65).…”

Section: Infrared Spectroscopymentioning

confidence: 99%

EXPLOSIVES DETECTION: A Challenge for Physical Chemistry

Steinfeld

Wormhoudt

1998

Annu. Rev. Phys. Chem.

397

242

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The detection of explosives, energetic materials, and their associated compounds for security screening, demining, detection of unexploded ordnance, and pollution monitoring is an active area of research. A wide variety of detection methods and an even wider range of physical chemistry issues are involved in this very challenging area. This review focuses on techniques such as optical and mass spectrometry and chromatography for detection of trace amounts of explosives with short response times. We also review techniques for detecting the decomposition fragments of these materials. Molecular data for explosive compounds are reviewed where available.

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“…The IR spectrum of RDX reveals prominent NO 2 stretch, N−N stretch, CH 2 -bending, and ring vibrational bands in the region 1600−600 cm −1 along with CH 2 -stretches in the 3100−3000 cm −1 region; these findings are in excellent agreement with the IR spectrum of RDX reported in the literature. 61,62 The thin film of RDX can exist in a crystalline or amorphous phase. The crystalline form of RDX shows sharp IR bands with narrow band width, whereas the amorphous phase of RDX exhibits broad and diffuse bands.…”

Section: Resultsmentioning

confidence: 99%

Probing the Reaction Mechanisms Involved in the Decomposition of Solid 1,3,5-Trinitro-1,3,5-triazinane by Energetic Electrons

Singh¹,

Zhu²,

Vuppuluri

et al. 2019

J. Phys. Chem. A

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The decomposition mechanisms of 1,3,5-trinitro-1,3,5-triazinane (RDX) have been explored over the past decades, but as of now, a complete picture on these pathways has not yet emerged, as evident from the discrepancies in proposed reaction mechanisms and the critical lack of products and intermediates observed experimentally. This study exploited a surface science machine to investigate the decomposition of solid-phase RDX by energetic electrons at a temperature of 5 K. The products formed during irradiation were monitored online and in situ via infrared and UV–vis spectroscopy, and products subliming in the temperature programmed desorption phase were probed with a reflectron time-of-flight mass spectrometer coupled with soft photoionization at 10.49 eV (ReTOF-MS-PI). Infrared spectroscopy revealed the formation of water (H2O), carbon dioxide (CO2), dinitrogen oxide (N2O), nitrogen monoxide (NO), formaldehyde (H2CO), nitrous acid (HONO), and nitrogen dioxide (NO2). ReTOF-MS-PI identified 38 cyclic and acyclic products arranged into, for example, dinitro, mononitro, mononitroso, nitro–nitroso, and amines species. Among these molecules, 21 products such as N-methylnitrous amide (CH4N2O), 1,3,5-triazinane (C3H9N3), and N-(aminomethyl)methanediamine (C2H9N3) were detected for the first time in laboratory experiments; mechanisms based on the gas phase and condensed phase calculations were exploited to rationalize the formation of the observed products. The present studies reveal a rich, unprecedented chemistry in the condensed phase decomposition of RDX, which is significantly more complex than the unimolecular gas phase decomposition of RDX, thus leading us closer to an understanding of the decomposition chemistry of nitramine-based explosives.

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Infrared and Raman Spectra of 1,3,5-Trinitro-1,3,5-Triazacyclohexane (RDX)

Cited by 16 publications

References 1 publication

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)

EXPLOSIVES DETECTION: A Challenge for Physical Chemistry

Probing the Reaction Mechanisms Involved in the Decomposition of Solid 1,3,5-Trinitro-1,3,5-triazinane by Energetic Electrons

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