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The Chemical Reactivity of 1,1-Diamino-2,2-dinitroethene (FOX-7)
No full text1,1-Diamino-2,2-dinitroethene (FOX-7), is an insensitive energetic material developed by the Swedish Defense Agency (FOA) in 1998. FOX-7, a ""push-pull"" nitroenamine, possesses a unique structure with interesting chemical properties that have not been fully understood. Its chemical unpredictability and poor solubility in common organic solvents have made the study of its chemical reactivity challenging. In our efforts to expand the chemistry of FOX-7 and to develop derivatives with superior energetic performance, we initiated work to develop the following areas: (1) Metal and salt chemistry, (2) FOX-7 based oxidizers, and (3) Azo-bridged derivatives of FOX-7.
Prior to our work, the only known metal chemistry of FOX-7 involved its potassium salt, KFOX, and no literature precedent had been found for the azo derivatives of FOX-7. We have been able to synthesize various silver and copper metal complexes of FOX-7 from simple amines via metathesis reactions. The completion of this work gave rise to the first metal complexes of FOX-7 and insight into of the behavior of FOX-7 as a coordinating ligand and an anion. In route to synthesizing desired azo-bridge substrates, we uncovered a new family of halogenated FOX-7 and halogenated azo-bridged FOX-7 derivatives. One of the most interesting features of this work was the discovery that these halogenated FOX-7 and halogenated azo-FOX-7 compounds behaved as hypergolic oxidizers. This is a new property of FOX-7 derivatives that had yet to be reported. Our contributions to the metal and azo chemistry of FOX-7 will be discussed.Thesis (Ph.D., Chemistry) -- University of Idaho, 201
Kinetics and chemistry of thermal decomposition of FOX 7
No full textS.70.1-70.13Formal kinetics of the two step decomposition of FOX 7 (1,1-diamino-2,2-dinitroethylene) was modelled using dynamic and isothermal DTA/TGA measurements. As a consequence of the extremely high values of the activation energy, FOX 7 is a very stable high explosive even at elevated temperatures. The reaction product (RP) remaining after the first decomposition step (corresponding to about 38 % mass loss) was investigated by NMR, X-ray diffraction, IR and HPLC. Surprisingly all methods seem to confirm the identity of the solid RP with the initial compound FOX 7. Consequently the compound decomposing in the first step is assumed to be a less stable amorphous fraction of FOX 7
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Thermal Properties of FOX-7
Full text linkMuch effort has been devoted to an ongoing search for more powerful, safer and environmentally friendly explosives. Since it was developed in the late 1990s, 1,1-diamino-2,2-dinitroethene (FOX-7), with lower sensitivity and comparable performance to RDX, has received increasing interest. Preliminary results on the physical and chemical characterization of FOX-7 have shown that it possesses good thermal and chemical stability. It is expected that FOX-7 will be a new important explosive ingredient in high performance, insensitive munition (IM) explosives. One of the major focuses in research on this novel energetic material is a study of its thermal properties. Oestmark et al have reported that DSC curves exhibit two minor endothermic peaks as well as two major exothermic peaks. Two endothermic peaks at {approx}116 and {approx}158 C suggest the presence of two solid-solid phase transitions. A third phase change below 100 C has also been reported based on a X-ray powder diffraction (XPD) study. The shapes, areas and observed temperatures of the two decomposition peaks at {approx}235 C and {approx}280 C vary with different batches and sources of the sample, and occasionally these two peaks are merged into one. The factors leading to this variation and a more complete investigation are in progress. Our laboratories have been interested in the thermal properties of energetic materials characterized by means of various thermal analysis techniques. This paper will present our results for the thermal behavior of FOX-7 including the phase changes, decomposition, kinetic analysis and the decomposition products using DSC, TG, ARC (Accelerating Rate Calorimetry), HFC (Heat Flow Calorimetry) and simultaneous TGDTA-FTIR (Fourier Transform Infrared Spectroscopy) Spectroscopy-MS (Mass) measurements
Enhancement of laser ignitibility of insensitive energetic materials (FOX‐7)
Full text linkExperimental investigation into the feasibility of optically sensitising an insensitive explosive, FOX-7 (1,1-Diamino-2,2-dinitroethene) by the doping of gold nanoparticles (GNPs) has been conducted. The commercially available GNPs were specifically designed in their particle shape and size to strongly absorb at the wavelength of the igniting laser (808 nm). The laser ignitibility of FOX-7 was significantly increased as the GNPs efficiently converted the absorbed energy into the heat. The laser ignitibility of such optically sensitised FOX-7 and the detonation capability of the laser initiator devices designed for the study were evaluated. Based on the evaluation of the initiator’s output in term of impact pressure, it was shown that an GNPs doped FOX-7 based laser slapper initiator was able to detonate a secondary explosive.Propellants, Explosives, Pyrotechnic
1,1-Diamino-2,2-dintroethene (FOX-7) in Copper and Nickel Diamine Complexes and Copper FOX-7
No full text1,1-Diamino-2,2-dinitroethene (FOX-7) reacts readily
with copper
nitrate in an aqueous solution of potassium hydroxide to form pea
green Cu(FOX)2(H2O)2 (5). FOX-7 complexes of
copper and nickel supported by a variety of diamines including Cu(en)2(FOX)2(H2O) (1), Cu(pn)2(FOX)2 (2), Cu(bipy)(FOX)2(H2O)4 (3a), Cu(bipy)2(FOX)2(H2O)2.5 (3b),
Cu(bipy)(FOX)2(DMSO)2·2DMSO (3c), Cu(phen)3(FOX)2(H2O)3 (4), (Ni)2(phen)6(FOX)4(NO3)3(H2O)2 (6), and Ni(bipy)3(FOX)2(H2O)4 (7a) were obtained via metathesis reactions
with potassium-FOX (K-FOX). Surprisingly FOX-7, in the presence of
Ni(II) and bipyridyl in a mixed solvent of methanol and dimethyl sulfoxide,
gave a chelated FOX carbamate anion resulting in the compound Ni(bipy)2(FOX–CO2)·(DMSO) (7b).
All metal salts were characterized by infrared, elemental analysis,
and differential scanning calorimetry (DSC). Single-crystal X-ray
diffraction structures were obtained for compounds 1, 2, 3c, 6, and 7b
1,1-Diamino-2,2-dintroethene (FOX-7) in Copper and Nickel Diamine Complexes and Copper FOX-7
No full text1,1-Diamino-2,2-dinitroethene (FOX-7) reacts readily
with copper
nitrate in an aqueous solution of potassium hydroxide to form pea
green Cu(FOX)2(H2O)2 (5). FOX-7 complexes of
copper and nickel supported by a variety of diamines including Cu(en)2(FOX)2(H2O) (1), Cu(pn)2(FOX)2 (2), Cu(bipy)(FOX)2(H2O)4 (3a), Cu(bipy)2(FOX)2(H2O)2.5 (3b),
Cu(bipy)(FOX)2(DMSO)2·2DMSO (3c), Cu(phen)3(FOX)2(H2O)3 (4), (Ni)2(phen)6(FOX)4(NO3)3(H2O)2 (6), and Ni(bipy)3(FOX)2(H2O)4 (7a) were obtained via metathesis reactions
with potassium-FOX (K-FOX). Surprisingly FOX-7, in the presence of
Ni(II) and bipyridyl in a mixed solvent of methanol and dimethyl sulfoxide,
gave a chelated FOX carbamate anion resulting in the compound Ni(bipy)2(FOX–CO2)·(DMSO) (7b).
All metal salts were characterized by infrared, elemental analysis,
and differential scanning calorimetry (DSC). Single-crystal X-ray
diffraction structures were obtained for compounds 1, 2, 3c, 6, and 7b
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Compatibility Study of 1,1-Diamino-2,2-Dinitroethene (FOX-7) with Some Energetic Materials
No full text1,1-diamino-2,2-dinitroethene (FOX-7) is a novel explosive with low sensitivity and high performance. The compatibility of FOX-7 with nine common energetic materials including hexanitrohexazaisowurtzitane (CL-20), cyclotetramethylenetetranitramine (HMX), cyclotrimethylenetrinitramine (RDX), 3,4-dinitrofurazanfuroxan (DNTF), 3-nitro-1,2,4-triazol-5-one (NTO), hexanitrostilbene (HNS-II), 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105), 2,4,6-triamino-1,3,5-trinitrobenzene (TATB), and 2,4,6-trinitrotoluene (TNT) were tested by differential scanning calorimetry (DSC) and the vacuum stability test (VST) as the thermal technique and X-ray diffractometry (XRD) as a nonthermal technique. DSC measurements showed that the binary systems of FOX-7/CL-20, FOX-7/HMX, FOX-7/NTO, and FOX-7/TNT were compatible in grade of A, the systems of FOX-7 with heat-resistant explosives including HNS-II, LLM-105, and TATB were compatible as well in grade of A-B, and the binary systems of FOX-7/DNTF and FOX-7/RDX had poor compatibility. VST results indicated that FOX-7 was compatible with nine energetic materials. Besides, the compatibility results of the thermal analysis were confirmed by the XRD technique
Interaction Mechanisms of Insensitive Explosive FOX-7 and Graphene Oxides from Ab Initio Calculations
No full textEnergetic material–graphene oxide (EM–GO) composites exhibit excellent thermal stability and insensitivity to mechanical stimuli. The interfacial interactions play an important role in affecting the structural and electrical properties of EM–GO composites. FOX-7 crystal with a wave-shaped layer structure is an ideal prototype system for matching with oxygen-rich GO monolayers to form FOX-7–GO composites. Here, we conducted a systematic investigation on FOX-7–GO composites by dispersion-corrected density functional approach. Our results revealed that there exists relatively strong interaction in the FOX-7–GO interface, which stems from the synergistic effect of interfacial charge transfer and hydrogen bonds. The electronic structure analyses demonstrated that GO can hybridize with FOX-7 to reduce charge accumulation on the FOX-7 surface. These theoretical results are useful for clarifying the interfacial effects on the sensitivity of FOX-7–GO composites
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