Observation of a solid-solid polymorphic transformation in 2,4,6-trinitrotoluene

Grabar, Donald G.; Rauch, F.; Fanelli, Anthony J.

doi:10.1021/j100844a073

Cited by 19 publications

(18 citation statements)

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“…Ref Already in 1969 it had been shown that an orthorhombic TNT polymorph on heating transforms endothermically to a monoclinic form before melting [18]. The enthalpy associated to this transition was found to be 0.27 kcal mol -1 (1.13 kJ mol -1 ; 4.97 J g -1 ) [18].…”

Section: Crystallographic Datamentioning

confidence: 99%

“…Furthermore, the authors reported three different sequences of thermal behavior reflected in the DSC curves ( Figure 1 and Table 2). The onset of the orthorhombic to monoclinic transition was observed in the temperature range of 63-64°C (336-337 K, peak a in Figure 1), whereas the onset temperature of the fusion of the monoclinic polymorph was found in the range of 78-80°C (351 -353 K, peak b in Figure 1) [18]. Specimens "Q1" and "Q2", which resulted in different thermal behavior (left-hand panel and center panel in Figure 1) possessed virtually the same X-ray diffraction pattern as the orthorhombic form solved by Golovina et al [8] (See Table S1 in the supplementary Materials), indicating that they must consist of the same orthorhombic polymorph, whereas specimen "An" (right-hand panel in Figure 1) was identified by the authors as the monoclinic polymorph.…”

Section: Crystallographic Datamentioning

confidence: 99%

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Topological pressure-temperature state diagram of the crystalline dimorphism of 2,4,6-trinitrotoluene

Céolin

Rietveld

2020

Fluid Phase Equilibria

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The phase behavior of explosive substances is important for the proper design of stable explosive devices. However, the equilibrium behavior of chemical compounds can be difficult to assess, because thermodynamic and kinetic behaviors are generally convoluted in the experimental results. The phase behavior of TNT is a case in point. A thorough review of the literature data demonstrates that the orthorhombic polymorph is the most stable under ambient conditions. Using the topological approach for the construction of a pressure-temperature phase diagram, it can be shown that all data is consistent with an overall enantiotropic system. Nonetheless, it is also clear that the differences between the orthorhombic and the monoclinic polymorphs are relatively small and that the driving force of interconversion between the two under ambient conditions is therefore limited.

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Section: Crystallographic Datamentioning

confidence: 99%

Section: Crystallographic Datamentioning

confidence: 99%

Topological pressure-temperature state diagram of the crystalline dimorphism of 2,4,6-trinitrotoluene

Céolin

Rietveld

2020

Fluid Phase Equilibria

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“…Samples of the two phases of TNT were prepared at DSTL, Fort Halstead, the monoclinic phase by melting flakes of TNT which were seeded by finely-ground material just as the melt was about to solidify (creamed TNT) and the orthorhombic phase by fast quenching of the molten material on a cold surface at -10°C 13 .…”

Section: Resultsmentioning

confidence: 99%

An NQR study of the crystalline structure of TNT

Deas

Gaskell

Long

et al. 2004

Detection and Remediation Technologies for Mines and Minelike Targets IX

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A comparison of the NQR parameters of the monoclinic and orthorhombic phases of TNT and their relation to the twist or dihedral angle between the plane of the NO 2 substituents and that of the benzene ring as determined in the X-Ray crystal structure analysis enables an assignment of different frequencies to specific sites in the two independent molecules in the unit cell of both forms to be made. The slow transformation of the metastable orthorhombic phase to monoclinic can then be followed by monitoring the NQR spectrum in which specific lines can be assigned to molecular sites in the two phases. NQR spectra of TNT referred to in the literature often differ; this could be due partly to the TNT often being a mixture of monoclinic and orthorhombic phases and partly to changes in the spectral line width, factors which must be taken into account when NQR is used to detect landmines.

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“…The SNR scales approximately as the 3/2 power of the resonant frequency 24 , providing RDX with an approximate 8-fold advantage over TNT. Secondly, TNT has two distinct crystalline forms with two molecules per unit cell in both forms [25][26][27][28] . With three structurally nonequivalent 14 N sites per molecule and three QR resonances for each site, there are a total of 36 resonances.…”

Section: Tnt and Rdx Qrmentioning

confidence: 99%

Advances in the engineering of quadrupole resonance landmine detection systems

Barrall¹,

Arakawa²,

Barabash³

et al. 2005

SPIE Proceedings

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Advances in the engineering of Quadrupole Resonance (QR) sensors for landmine detection have resulted in improved performance, as well as massive reductions in power, size and weight. The next generation of vehicle-mounted QR confirmation sensors is over an order of magnitude smaller and more power efficient than the system fielded in 2002 and 2003. Early prototypes have also demonstrated a significant improvement in TNT sensitivity, and similar improvements are anticipated in RDX sensitivity during Q1 2005. Blind test results from 2003 confirm the radio frequency interference and piezo-electric ringing immunity of the Quantum Magnetics QR Confirmation Sensor (QRCS).

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Observation of a solid-solid polymorphic transformation in 2,4,6-trinitrotoluene

Cited by 19 publications

References 1 publication

Topological pressure-temperature state diagram of the crystalline dimorphism of 2,4,6-trinitrotoluene

Topological pressure-temperature state diagram of the crystalline dimorphism of 2,4,6-trinitrotoluene

An NQR study of the crystalline structure of TNT

Advances in the engineering of quadrupole resonance landmine detection systems

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