Kinetics of reversible polymorphic transition in energetic materials. Phase transitions α → β and β → α in 1,1-diamino-2,2-dinitroethylene

Захаров, В. В.; Чуканов, Н. В.; Chervonnyi, A. D.; Vozchikova, S. A.; Korsounskii, B. L.

doi:10.1134/s1990793114110104

Cited by 8 publications

(11 citation statements)

References 10 publications

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“…As follows from [35], the stability of β-HMX in the PT β → δ is reduced with an increase in crystal size. A similar regularity was noted in [34]: a coarse sample showed phase conversion from the β-to the δ-phase, starting during the first 10 minutes at 165 °C. It required up to 4 h for completion.…”

Section: Irreversible Pt Frontal and Quasi-homogeneous Modesmentioning

confidence: 63%

“…In contrast to this, the PT α → β in FOX-7, in the temperature interval from 100.0 to 111.8 °С, is characterized by E a = 110 kJ/mol [34], and is reversible.…”

Section: Reversible Ptsmentioning

confidence: 87%

“…In the case of HMX, a fine crystalline sample characterized by a very narrow particle size distribution (average size 20 μm) was used. In the FOX-7 sample used in [34], two kinds of crystals were present. Crystals of the first type (Figure 11, right) are parallelepiped, formed by the faces {100}, {010} and {001}.…”

Section: Reversible Ptsmentioning

confidence: 99%

“…In other words, in reverse PTs the nucleation stage is not observed. In [34], the kinetics of the reverse PT β → α in FOX-7 at 23 °C was followed by the intensity of the absorption band of the bending vibrations of NO 2 groups at 738 cm -1 , which is present only in the IR spectrum of the α-modification (Figure 9). The process follows the two-exponential law (Figure 10) in accordance with the equation:…”

Section: Reversible Ptsmentioning

confidence: 99%

“…The quasi-homogeneous PT α → β in FOX-7 occurs with an activation energy of ~110 kJ/mol. This value may correspond to the cleavage of several hydrogen bonds in the growth stage [34].…”

Section: The Role Of Mechanical Effects On Pts Of Molecular Crystalsmentioning

confidence: 99%

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Kinetics of Polymorphic Transitions in Energetic Compounds

Чуканов¹,

Захаров²,

Korsunskiy³

et al. 2016

Cent. Eur. J. Energ. Mater.

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Available data on the kinetics of polymorphic transitions (PTs) in energetic compounds under isothermal conditions are summarized and discussed. It is shown that the general kinetic regularities of these processes (stepwise and continuous regimes) depend on their topotactic mode (frontal or quasihomogeneous, respectively). In reverse PTs, a nucleation stage is not observed, which is explained by the presence of nuclei of the low-temperature polymorph in the preheated sample. The influence of mechanical effects on the kinetics of PTs in molecular crystals is discussed.

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Section: Irreversible Pt Frontal and Quasi-homogeneous Modesmentioning

confidence: 63%

“…In contrast to this, the PT α → β in FOX-7, in the temperature interval from 100.0 to 111.8 °С, is characterized by E a = 110 kJ/mol [34], and is reversible.…”

Section: Reversible Ptsmentioning

confidence: 87%

Section: Reversible Ptsmentioning

confidence: 99%

Section: Reversible Ptsmentioning

confidence: 99%

“…The quasi-homogeneous PT α → β in FOX-7 occurs with an activation energy of ~110 kJ/mol. This value may correspond to the cleavage of several hydrogen bonds in the growth stage [34].…”

Section: The Role Of Mechanical Effects On Pts Of Molecular Crystalsmentioning

confidence: 99%

See 3 more Smart Citations

Kinetics of Polymorphic Transitions in Energetic Compounds

Чуканов¹,

Захаров²,

Korsunskiy³

et al. 2016

Cent. Eur. J. Energ. Mater.

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High‐Temperature Structural Transformations of 1,1‐Diamino‐2,2‐dinitroethene (FOX‐7)

Захаров

Чуканов

Дремова

et al. 2016

Propellants Explo Pyrotec

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Stuctural transformations of 1,1‐diamino‐2,2‐dinitroethene (FOX‐7) were investigated in the temperature range 298–513 K by means of DSC, TG, isothermal calorimetry, PXRD, IR spectroscopy, and electron microscopy. The data obtained confirm the existence of the high‐temperature δ‐FOX‐7 polymorph stable above 480 K. The heat effect of the γ→δ transformation is − 4.6 J g−1 (−680 J mol−1). Metastable γ‐phase formed in the reverse process δ→γ has a perfect crystal structure and is stable towards thermal decomposition. Possible mechanisms of sharp deceleration of thermal decomposition of FOX‐7 at the 40 % conversion are discussed.

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Investigation of FOX‐7 Polymorphs: new polymorphs – ϵ and ζ

et al. 2021

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Polymorphism of 1,1‐diamino‐2,2‐dinitroethene (FOX‐7, DADNE) has investigated by X‐ray powder diffraction (XRD), differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), IR‐spectroscopy. Two previously unknown polymorph modifications of FOX‐7 ‐ ϵ and ζ were discovered. ϵ‐FOX‐7 has prepared by hydrolysis of 2‐(dinitromethylene)‐5,5‐dinitropyrimidine‐4,6(1H,3H,5H)‐dione in a media with pH up 7–8 to Ho≈−3 and 2‐(dinitromethylene)imidazolidine‐4,5‐dione in aqueous ammonia. ϵ‐FOX‐7 is a stable and exists in temperature range 273–378 K. ζ‐polymorph of FOX‐7 can be obtained at ϵ‐FOX‐7 heating to 378–380 K. ζ→ϵ polymorph transition is a reversible and occurs at 361.7±3.1 K. At 433–453 K ζ‐FOX‐7 transforms to γ‐polymorph. ζ→γ phase transition temperature range was determined using IR‐spectroscopy because it is invisible on DSC curves. IR‐spectra of ϵ and ζ polymorphs are significantly distinct from α‐, β‐ and γ‐FOX‐7. ϵ‐FOX‐7, in contrast to monoclinic α‐polymorph, has orthorhombic type of crystal system (space group P212121). Based on received data, new scheme of FOX‐7 polymorph transition is proposed.

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Kinetics of reversible polymorphic transition in energetic materials. Phase transitions α → β and β → α in 1,1-diamino-2,2-dinitroethylene

Cited by 8 publications

References 10 publications

Kinetics of Polymorphic Transitions in Energetic Compounds

Kinetics of Polymorphic Transitions in Energetic Compounds

High‐Temperature Structural Transformations of 1,1‐Diamino‐2,2‐dinitroethene (FOX‐7)

Investigation of FOX‐7 Polymorphs: new polymorphs – ϵ and ζ

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