The thermal decomposition of 1,1-diamino-2,2-dinitroethene (I) and its cyclic derivatives 2-(dinitromethylene)-1,3-diazacyclopentane (II), 2-(dinitromethylene)-1,3-diazacyclohexane (III) and 2-(dinitromethylene)-1,3-diazacycloheptane (IV) was investigated by quantum chemistry methods (PBE/cc-pVDZ), as well as DSC and TG. According to both the theoretical and experimental data, the thermal stability of compounds I-IV increases in the sequence IV < I ≈ III < II.
In the present paper, 2,4-dinitroanisole (DNAN) has been evaluated as a melt cast explosive in comparison to the widely used 2,4,6-trinitrotoluene (TNT). The detonation failure diameter of a bare DNAN charge is greater than 100 mm and about 44 mm with 1.5 mm steel confinement. Comparative studies of two sets of formulations were carried out. The first set comprised formulations containing 60% of NTO, FOX-7, HMX or RDX and 40% of DNAN or TNT. The second set comprised formulations containing 30% of NTO, FOX-7, TATB or RDX and 70% of DNAN or TNT. The studies were mainly concentrated on characterization of the formulations, which included determination of the sensitivity parameters and the velocity of detonation (VOD). The study confirmed that DNAN and DNAN-based formulations are relatively insensitive compared to TNT and the analogous TNT-based formulations respectively. The rate of the detonation reaction of DNAN is enhanced in the presence of the high energy ingredients RDX, HMX, FOX-7 and NTO to varying degrees. The VODs of the FOX-7/TNT and RDX/TNT formulations match closely with the proportions of FOX-7 and RDX under study. The VOD and shock sensitivity of the FOX-7/DNAN formulations decrease rapidly compared to the RDX/DNAN formulations, with increases in the proportion of FOX-7 or RDX. The combinations of NTO with TNT, and NTO with DNAN, are more shock insensitive than TNT or DNAN alone. NTO-based compositions are more insensitive than FOX-7-based compositions.
The influence of polymeric matrices on the physical properties and stability of polymer bonded explosives based on FOX-7 (1,1-diamino-2,2-dinitroethene) and HMX (1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane) was investigated. Samples of explosives were prepared with different polymeric additives e.g. nonylphenylpolyoxyethyleneglycol ethers (ROKAFENOL), silicone greases and poly(3-methyl-3-nitroxymethyloxetane) (Poly(NIMMO)). The mass ratio of polymeric matrices to explosives was determined experimentally in order to obtain plastic samples stable at room temperature. The most promising products were tested for sensitivity to mechanical and thermal stimuli. Determinations of the critical diameter and detonation velocity were also performed. The use of silicone grease in the mixture containing Poly(NIMMO) gave the most desirable results, that is to say a combination of high performance and high stability.
A melt-cast composition containing NTO, FOX-7, TNT, Al and wax was prepared and tested. The viscosity of the melted composition was measured. Its sensitivity to impact, friction, shock wave and jet impact were determined, and its thermal stability and ignition temperature were established. Some detonation properties of the composition were investigated. The heat of detonation was measured using a calorimetric bomb. The detonation pressure and velocity were determined in a plate-dent test. The results of a cylinder test were used for the determination of the Gurney energy, the detonation pressure and energy, and the so-called effective exponent of the expansion isentrope and the JWL equation of state of the detonation products.
1,1-diamino-2,2 dinitroethylen (DADNE, FOX-7) is a novel explosive with low sensivity. The valuable properties is a result of specific chemical construction, in which inter- and intramolecular hydrogen bonds stabilize the structure. From the reason of low sensivity, FOX-7 has a very broad spectrum of use for elaborating many kinds of munnition. Hence a very important aspect is to conduct the research of this substance to determine chemical purity, assay content of water etc. The HPLC method is the one of the analytical technique which has a very high precision of determination of the purity and assay of the substance. The aim of this work was to compile a new method of the assay and purity determination of FOX-7. The C18-Xbridge column and the mobile phase: Acetonitryle: Water: Triethylamine were used. Through application of the C18- XBridge column and mobile phase the substrate MPD and main substance FOX-7 had very good resolution and the analysis time was relatively short. The validation of the new method has been performed: selectivity, specificity, linearity, precision, assay and limits of detection and quantitation. We have also checked the stress tests of the FOX-7 in acidic, basic and oxidative conditions.
PL
1,1-diamino-2,2 dinitroetylen (DADNE, FOX-7) jest nowoczesną małowrażliwą substancją wybuchową. Jej cenne właściwości są rezultatem specyficznej budowy chemicznej, w której wewnątrz i zewnątrz cząsteczkowe wiązania wodorowe stabilizują strukturę, powodując jej małą wrażliwość na bodźce. Dzięki takim właściwościom, FOX-7 może być zastosowany do elaboracji wielu rodzajów małowrażliwej amunicji. Dlatego tak ważnym aspektem jest prowadzenie badań chemicznych uwzględniających czystość i zawartość chemiczną tej substancji. Metoda HPLC jest nowoczesną techniką, szeroko stosowaną do określenia tych parametrów z dużą dokładnością i precyzją. Celem naszej pracy było zwalidowanie nowej metody oznaczania czystości i zawartości FOX-7. Do oznaczania tych parametrów użyto kolumny C-18 X-Bridge natomiast jako fazy ruchomej mieszaniny acetonitrylu trietyloaminy: wody zmieszanej w odpowiednim stosunku. Zastosowanie właśnie takiej kolumny oraz fazy z modyfikatorem pozwoliło na podzielenie zanieczyszczenia MPD od substancji głównej w odpowiednio krótkim czasie z dobrą rozdzielczością oraz symetrią pików. Walidacja metody obejmowała: selektywność, specyficzność, precyzję, dokładność oraz limity detekcji oraz oznaczalności. Podczas walidacji zostały również przeprowadzone testy stresowe w warunkach kwaśnych, zasadowych oraz utleniających.
The key driving force in modern explosive research is the development of low vulnerable high explosive (LOVEX) compositions for future applications in insensitive munitions (IMs). The increasing demand for LOVEX has led to exhaustive studies on low vulnerable explosives as a replacement for conventional cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX) in 2,4,6-trinitrotoluene (TNT) melt cast high explosive formulations. In the present study, 1,1-diamino-2,2dinitroethene (FOX-7) has been evaluated as a possible RDX replacement in TNT based, non-aluminized as well as aluminized, melt cast formulation. FOX-7 based melt cast formulations were characterized for their sensitivity to mechanical/shock stimuli, velocity of detonation (VOD), blast parameters and thermal decomposition behavior. These characteristics are compared with the corresponding RDX based compositions as reference standard. The studies show that with little sacrifice on performance parameters, FOX-7 based, non-aluminized and aluminized, melt cast formulations are found to be less vulnerable, compared with the corresponding RDX based formulations.
A non-aqueous titration method was developed to assay the insensitive high explosive 1,1-diamino-2, 2-dinitroethene (FOX-7). The weak acidic nature of FOX-7 (pKa 10.6) was exploited in the assay method. The sample was dissolved in the protophilic solvent N, N-dimethylformamide and titrated against sodium methoxide solution in benzene/methanol using azo violet as indicator. FOX-7 samples obtained from regular batch operations were assayed by this method and the results were compared with that of a recrystallized sample. The method is simple, rapid and has good accuracy and precision.
W niniejszej pracy dokonano optymalizacji procesu otrzymywania 1,1-diamino-2,2-dinitroetenu (FOX-7, DADNE ) w wyniku nitrowania jego bezpośredniego prekursora 2-metylopirymidyna-4,6-dionu (MPD). Zaproponowane modyfikacje obejmujące zarówno proces otrzymywania FOX-7 jak i MPD, pozwalają na prowadzenie szybszej i wydajniejszej oraz bezpieczniejszej syntezy tych związków. Dokonano pomiaru efektu cieplnego generowanego podczas procesu nitrowania MPD. Zmodyfikowane parametry procesu mogą być wykorzystane do otrzymywania FOX-7 w skali wielkolaboratoryjnej i półtechnicznej.
EN
In the paper, optimization of 1,1-diamine-2,2-dinitroethene (FOX-7) and its precursor, 2-methylpirymidyne-4,6-dion (MPD), syntheses are presented. The proposed modifications make it possible to synthesize both of the compounds in more efficient, faster, and safer processes. Heat effects of the MPD nitration were measured. The results obtained can be used to design equipment and to formulate procedure of FOX-7 production in a pilot scale process.
Perchlorate complexes of d-metals with tetrazole-containing ligands are proposed for application both as explosives for safe initiation systems and as modifers of burning rate for propellants. However, the problem of compatibility of organic polynitro compounds with the complexes has not yet been solved. In the present article the results of investigation of the infuence of perchlorate complexes of cobalt, copper and nickel with 1,5-pentamethylentetrazole as a ligand on thermal decomposition of energetic materials ranging from 1,1-diamino-2,2- dinitroethylene (FOX-7), to cyclic cyclotetramethylenetetranitroamine (HMX) and caged hexanitrohexaazaizowurtzitane (CL-20) have been reported. Thermal stability of the individual compounds and their mixtures with coordination complexes has been assessed on the basis of differential thermal analysis and the study of ignition temperatures after 5-second delay. The fraction of the complexes in the formulations with polynitro compounds amounted to ~10%.
X-ray powder diffraction (XRD) is an established tool for the investigation of energetic materials. Whereas positions and intensities of diffraction peaks yield information on the crystal structure, peak profles are related to the real structure described by crystallite size, shape and microstrain. A series of energetic materials were measured at the synchrotron ANKA, and the size/strain broadening of FOX-7, RDX and ADN is discussed in relation to crystal structures and properties.
This paper presents the results of thermodynamical calculations and investigations of the thermochemical and balistic properties of aluminized composite solid propellants Binder/AP/A1 containing FOX-7. The calculation was conducted by using ICT-Thermodynamic Code. The heat of combustion was determined in a stationary bomb calorimeter IKA C 4000. The breakdown temperatures were taken with the DTA 551 Ex measuring apparatus and the burning rate was measured in a subscale rocket motor utilizing the ESAM v. 3.3.0 system. It was revealed that the introduction of FOX -7 into the propellant composition causes a reduction of the energetic characteristics and the burning rate of the propellant.
Modern rocket propellants contain inter alia nitroamines (i.e. RDX, HMX). Therefore, the detonation properties of composite solid propellants are very important for good functioning of rocket motors and for storage. One of the new materials of that kind, with low sensitivity, is FOX-7 which was applied here as one of the components of composite solid propellant. This paper presents the thermodynamical calculations and thermochemical research results as well as the results of a study of transition into detonation of an aluminized composite propellant containing HMX. The said properties were compared with those of a propellant containing FOX-7.
W pracy otrzymano i zbadano właściwości detonacyjne flegmatyzowanego materiału wybuchowego FOX-7 (1,1-diamino-2,2-dinitroeten - DADNE) oraz jego mieszaniny z oktogenem. Wyznaczono dla tych materiałów prędkość i ciśnienie detonacji, zdolności miotające oraz energię detonacji. Określono wrażliwość na bodźce mechaniczne: tarcie, uderzenie i falę uderzeniową. Zbadano ich stabilność termiczną i kompatybilność składników. Praca jest kontynuacją poszukiwań nowych kompozycji do zastosowania w małowrażliwej amunicji.
EN
Phlegmatized FOX-7 (1,1-diamino-2,2-dinitroethylene - DADNE) and its mixture with HMX were prepared and their detonation properties were investigations. The detonation velocity, detonation pressure, acceleration ability and detonation energy were established. The sensitivity on mechanical stimuli (friction, impact and shock wave) was determined. Thermal stability and compatibility of composition were also tested. This work continues the investigation of new compositions for low vulnerability ammunition.
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The crystal quality and the internal microstructure of crystals have a great influence on the sensitivity of energetic materials. Besides, the particle size and the particle size distribution are of great importance to the processing technology of energetic materials. Particle properties can especially be influenced by applying different crystallization techniques, such as cooling crystallization, membrane crystallization, emulsion crystallization and others. The objective of the investigations was to determine the interrelationship between the properties of the gained crystals and the process parameters. Special attention was directed to the qualitative and quantitative examination of crystal defects and their dependence on the experimental conditions. Besides, the morphology and structure of crystals were calculated by molecular modelling. The effect of crystal defects on the sensitivity of the material was tested on different collectives of particles having varying amount of crystal defects.
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