BAM Fallhammer Research Articles

Study on synthesis and characterization of spherical copper(I) 5‐nitrotetrazolate (DBX‐1)

AbstractTraditional primary explosives often contain heavy metals, especially toxic lead, such as lead azide (LA) and lead styphnate (LS) that can cause environmental pollution problems. Copper(I) 5‐nitrotetrazolate (DBX‐1) is a green primary explosive without toxic heavy metals, which is considered as one of the most promising alternatives to LA. DBX‐1 is usually synthesized from sodium 5‐nitrotetrazolate dihydrate (NaNT ⋅ 2H2O) and copper(I) chloride (CuCl). However, most of the synthesized products are irregular flakes with poor flowability, which affects the loadability. In this study, dextrin was used as a crystal shape modifier to improve the morphology of the synthesized product. Taguchi analysis method was used to determine the optimal experimental conditions for obtaining the spherical DBX‐1 with smaller particle size. The synthesized products were characterized by SEM, FTIR, UV‐Vis, STA TG‐DSC and VST, and their sensitivity was determined by BAM fallhammer, BAM friction tester and electrostatic spark sensitivity tester. The experiment results showed that the optimal combination of synthesis parameters was the NaNT ⋅ 2H2O concentration of 4.4 wt.%, the reaction temperature of 100 °C, the reaction time of 75 min and the additional dextrin solution of 5.0 mL. The average particle size of the synthesized spherical DBX‐1 was 33.0 μm. The decomposition activation energy was calculated by Kissinger method and Ozawa method to be 178.5 and 178.8 kJ/mol, respectively. The compound had good chemical stability. In addition, the sensitivity of spherical DBX‐1 was lower compared to that of flaky DBX‐1 and LA.

IMPACT SENSITIVITY OF NITROMETHANE-BASED GREEN-PROPELLANT PRECURSOR MIXTURES

Nitromethane is a promising green propellant candidate. However, one potential issue for industrial use may be its high sensitivity to mechanical impact. In this paper, we assess the effect of adding several phlegmatizing substances (or inhibitors as we call them), on the impact sensitivity and the potential propulsive performance of the resulting mixtures. The impact sensitivity of the nitromethane mixtures was characterized using a BAM Fallhammer impact tester. The theoretical rocket performance of the mixtures was calculated utilizing the NASA CEA program. This study resulted in the identification of several nitromethane-inhibitor mixtures, which lack the high impact sensitivity of pure nitromethane but still retain much of its propulsive performance. The most promising approach was the addition of 6 wt.% of dimethyl sulfoxide: the theoretical specific impulse was only decreased by 3%, while the impact sensitivity was significantly lowered (> 10 J vs. < 5 J, as in pure nitromethane).

Preliminary Study on Characteristics of NC/HTPB-Based High-Energy Gun Propellants

This study mainly explored the characteristics of NC/HTPB-based high-energy gun propellants with RDX, CL-20 or TKX-50 by experimental method. Three series of test samples were prepared referring to the formulation of M1 single-base gun propellant (M1 SBP). The thermochemical characteristics, chemical stability, explosion heat, impact and friction sensitivities of prepared samples were determined by simultaneous differential scanning calorimetry–thermogravimetric analysis (STA DSC–TGA), vacuum stability tester (VST), bomb calorimeter (BC), BAM fallhammer and BAM friction tester, respectively, and compared with those of the reference sample M1. The experimental results indicated that the thermochemical characteristics of NC/HTPB-based high-energy gun propellants were similar to those of M1 SBP. The NC/HTPB-based high-energy gun propellants had good chemical stability and were superior to M1 SBP. The explosion heat of NC/HTPB-based high-energy gun propellants was close to and slightly larger than that of M1 SBP. In addition, the NC/HTPB-based high-energy gun propellants had lower impact and friction sensitivities than the M1 SBP. Therefore, the NC/HTPB-based high-energy gun propellants have the potential to replace the M1 SBP. The combustion performances of NC/HTPB-based high-energy gun propellants will be continuously studied and verified in the future.

Impact and Friction Sensitivities of PETN: I. Sensitivities of the Pure and Wetted Material

AbstractPentaerythritol tetranitrate (PETN) is a sensitive and brisant explosive. PETN is transported wetted (25 %) with water to limit its impact and friction sensitivities. Literature on its sensitivities in function of its water content is controversial as the measurements were performed by several operators and laboratories rendering difficult to compare the values. Literature studies of mechanical sensitivity methods show the weaknesses and problems of mechanical measurements. Indeed, it is important to analyze a sample with standardized machines and by a single operator. During this work, pure PETN samples with water contents of 0 to 35 % were prepared and the water content was measured by Karl‐Fischer titration. The sensitivities were analyzed by the “BAM Fallhammer” and the “BAM Friction Apparatus”. The resulting trends were analyzed and discussed with regard to their meaning for handling safety. The study should help to better assess dangers when working with wet PETN (10–25 %) in order to avoid accidents.

5-Nitrotetrazol and 1,2,4-Oxadiazole Methylene-Bridged Energetic Compounds: Synthesis, Crystal Structures and Performances.

A new structural type for melt cast materials was designed by linking nitrotetrazole ring with 1,2,4-oxadiazole through a N-CH2-C bridge for the first time. Three N-CH2-C linkage bridged energetic compounds, including 3-((5-nitro-2H-tetrazol-2-yl) methyl)-1,2,4-oxadiazole (NTOM), 3-((5-nitro-2H-tetrazol-2-yl)methyl)-5-(trifluoromethyl)-1,2,4 -oxadiazole (NTOF) and 3-((5-nitro-2H-tetrazol-2-yl)methyl)-5-amine-1,2,4-oxadiazole (NTOA), were designed and synthesized through a two-step reaction by using 2-(5-nitro-2H-tetrazole -2-yl)acetonitrile as the starting material. The synthesized compounds were fully characterized by NMR (1H, 13C), IR spectroscopy and elemental analysis. The single crystals of NTOM, NTOF and NTOA were successfully obtained and investigated by single-crystal X-ray diffraction. The thermal stabilities of these compounds were evaluated by DSC-TG measurements, and their apparent activation energies were calculated by Kissinger and Ozawa methods. The crystal densities of the three compounds were between 1.66 g/cm3 (NTOA) and 1.87 g/cm3 (NTOF). The impact and friction sensitivities were measured by standard BAM fall-hammer techniques, and their detonation performances were computed using the EXPLO 5 (v. 6.04) program. The detonation velocities of the three compounds are between 7271 m/s (NTOF) and 7909 m/s (NTOM). The impact sensitivities are >40 J, and the friction sensitivities are >360 N. NTOM, NTOF and NTOA are thermally stable, with decomposition points > 240 °C. The melting points of NTOM and NTOF are 82.6 °C and 71.7 °C, respectively. Hence, they possess potential to be used as melt cast materials with good thermal stabilities and better detonation performances than TNT.

Enhanced friction and shock sensitivities of hexachlorodisilane hydrolyzed deposit mixed with KOH

In this work, the effects of potassium hydroxide (KOH) on friction and shock sensitivity of the hexachlorodisialne hydrolysis products were studied. A wide range of KOH content, from 0.02 to 21.5 wt%, in the mixture of KOH and HCDS hydrolyzed deposit was prepared by mixing the deposit with aqueous KOH solution and dried in glovebox. The lowest impact energy (LIE) and lowest friction force (LFF) were determined by BAM fall-hammer and friction test apparatus, respectively. It was found that both shock and friction sensitivities increased with an increase in the KOH content in the HCDS hydrolyzed deposit. In particular, the LIE and LFF decrease from 6 J to 326 N of the original deposit to less than 0.125 J and 7 N for deposit with 0.03 and 0.3 wt% KOH. Differential scanning calorimetry studies showed that a new exothermic peak was observed between 80 °C and 150 °C which is also accompanied by evolution of hydrogen. It is proposed that, the presence of KOH results in the formation of Si–Si–OK groups leading to the weakening of the neighboring Si–Si bonds. Any mechanical impact or friction will lead to the cleavage of the unstable Si–Si bonds and subsequently initiate a fast chain oxidation of adjacent Si–Si and Si–OH bonds to form more Si–O–Si groups, releasing H2 gas and heat. Recommendations were given for handling and disposing of these explosive deposits.

Optimization of Synthesis Parameters and Characterization of Green Primary Explosive Copper(I) 5‐Nitrotetrazolate (DBX‐1)

AbstractSince the early 20th century, lead azide (LA) has been commonly used as a primary explosive. However, lead pollution in the air and soil has attracted more and more attention, particularly in military training grounds and shooting ranges. Copper(I) 5‐nitrotetrazolate (DBX‐1) is considered as one of the most promising alternatives to LA. DBX‐1 is typically prepared from sodium 5‐nitrotetrazolate dihydrate [NaNT(H2O)2] and copper(I) chloride (CuCl). But little is known about its optimal synthesis parameters. In addition, NaNT(H2O)2 is not commercially available. In this study, NaNT(H2O)2 was prepared by ourselves. Taguchi's experimental design method was used to determine the optimal experimental conditions for obtaining the maximum yield of DBX‐1. The synthesized NaNT(H2O)2 and DBX‐1 were identified by means of SEM, NMR, FTIR, EA, UV‐Vis and STA TG‐DSC, and the sensitivity of DBX‐1 was determined using BAM fallhammer, BAM friction tester and electrostatic spark sensitivity tester. The experimental results indicated that the optimal synthesis parameters of DBX‐1 were as follows: the reaction temperature was 100 °C, the reaction time was 30 min, the concentration of NaNT(H2O)2 was 0.075 wt.% and the molar ratio of NaNT(H2O)2 to CuCl was 1.15, and then the maximum yield after purification could reach 72.2 %. The decomposition activation energies of DBX‐1 calculated by Kissinger and Ozawa methods were 178.6 and 179.0 kJ/mol, respectively. In addition, the impact sensitivity, friction sensitivity and electrostatic spark sensitivity of DBX‐1 were 51 mJ, 0.4 N and 7.3 mJ, respectively, which were almost the same as those for LA.

Study on Synthesis and Characterization of Primary Explosive KDNBF with Different Morphologies

AbstractTraditional primary explosives are usually heavy metal salts, especially salts of lead, such as lead azide (LA) and lead styphnate (LS), which can cause environmental pollution problems. The potassium salt of 4,6‐dinitrobenzofuroxan (KDNBF) has attracted more and more attention due to its advantages of no heavy metal pollution to the environment and appropriate sensitivity. There are many reports on the thermal properties and applications of KDNBF, but few reports on the morphological properties. In addition, little is known about the optimal synthesis conditions of KDNBF with different morphologies in the preparation process. In this study, Taguchi's experimental design method was used to determine the optimal experimental conditions for obtaining the maximum yields of KDNBF with different morphologies. The synthesized KDNBF was identified by means of SEM, NMR, FTIR, EA, and TG‐DSC, and its sensitivity was measured using BAM fallhammer, BAM friction tester, and electrostatic spark sensitivity tester. The experimental results indicated that the maximum yields of flaky and spherical KDNBFs could reach 85.6 % and 82.6 % after purification under the optimal experimental condition, respectively. The spherical KDNBF powder had a relatively denser structure than the flaky KDNBF powder. The thermal analyses showed that the activation energies of the decomposition reaction of the flaky and spherical KDNBF powders calculated by the Kissinger method were 171.5 and 188.5 kJ mol−1, respectively, and the Ozawa method were 170.7 and 186.9 kJ mol−1, respectively. The thermal stability of spherical KDNBF powder was higher than that of flaky KDNBF powder. In addition, the sensitivity tests showed that the spherical KDNBF powder was less sensitive than the flaky KDNBF powder.

Optimization of the Process Parameters for the Synthesis of High Purity 4,6‐Dinitrobenzofuroxan (4,6‐DNBF)

Abstract4,6‐Dinitrobenzofuroxan (4,6‐DNBF) is explosive and can also be used as an important intermediate in the synthesis of other explosives. It can be prepared by nitrating benzofuroxan (BF) with mixed nitric/sulfuric acid. However, little is known about its optimal synthesis parameters in the preparation process. In this study, Taguchi's experimental design method was used to improve the yield of 4,6‐DNBF. A L9 (34) orthogonal array with four control factors and three levels of each control factor was used to design nine experimental conditions. The experimental data were transformed into a signal‐to‐noise (S/N) ratio to analyze and evaluate the experimental conditions of the optimal parameter combination for the maximum yield of 4,6‐DNBF. The verification results indicated that the optimal synthesis parameters were as follows: nitration temperature was 40 °C, mass ratio of BF to H2SO4, was 1 : 15, volume ratio of HNO3 to H2SO4 was 1 : 2.0 and reaction time was 4 hours, and then the maximum crude yield and the maximum yield after purification could reach 73.2 % and 49.0 %, respectively. Furthermore, the synthesized 4,6‐DNBF was identified by scanning electron microscopy (SEM), nuclear magnetic resonance spectrometer (NMR), Fourier transform infrared spectrometer (FTIR), elemental analyzer (EA), ultraviolet‐visible spectrometer (UV‐Vis) and thermogravimetry‐differential scanning calorimetry (TG‐DSC), and its sensitivity was determined using BAM fallhammer, BAM friction tester, and electrostatic spark sensitivity tester.

The Unique Synthesis of a Green Metal‐Free Primary Explosive: 3,3′‐azo‐5,5′‐diazido‐1,2,4‐triazole

AbstractThe unique synthesis of 3‐azido‐5‐amino‐1,2,4‐triazole (1) and a possible reaction process were described. The target compound 3,3′‐azo‐5,5′‐diazido‐1,2,4‐triazole (2) was obtained by further coupling reaction of compound 1 with potassium permanganate. Compound 2 was well characterized by NMR spectra, IR spectroscopy, elemental analysis, differential scanning calorimetry (DSC), and single crystal X‐ray diffraction. The sensitivities towards impact and friction of 2 were characterized by BAM Fallhammer and BAM Friction. Compound 2 exhibited good density (1.68 g cm−3), good thermal stability (193 °C), high heat of formation (1345.1 kJ mol−1/5.468 kJ g−1), excellent detonation performance (26.7 GPa, 8345 m s−1 ) and acceptable sensitivity (IS=6 J, FS=72 N, EDS=0.224 J). Moreover, compound 2 was tested for its priming ability by detonating RDX. The result indicates that compound 2 could be used as a potential green metal‐free primary explosive.

Influence of Temperature on Impact Sensitivity of Matchhead Composition while in Contact with Different Process Materials

This research work aims to understand the influence of temperature (upto 80°C) on the impact sensitivity of matchhead composition with various process contact materials (Steel, aluminium, brass) and to find out the critical temperature for process safety. The BAM fall hammer was modified with a heating element for the measurement of impact sensitivity. The Limiting Impact Energy (LIE) at ambient temperature condition with steel surface on the top and bottom was found to be 3.73J. The lowest critical temperature was found to be 60.14°C for the matchhead composition when it is in contact with steel, which was used as the contact material for both top and bottom.

Influence of Different In-Process and Building Materials with Varying Hardness on Impact Sensitivity of the Matchhead Composition

The objective of this research work is to study the influence of different in-process contact materials (steel, aluminium and brass) and building contact materials (concrete and wood), and its hardness on the impact sensitivity of matchhead composition. The BAM fall hammer was used for measurement of impact sensitivity. The result demonstrated that the in-process and building contact materials, and its hardness imparted variation to the sensitivity between 3.33J and 15.892J. The least LIE was found at 3.33J for the steel at 115 HRB and 117 HRB; 3.72J for aluminium at 53 HRB; 4.7J for brass at 82 HRB; 12.16J for concrete at 35 RHN, and 13.14J for wood at 16 HRB. The limited impact energy was lowest when there was contact between steel and steel as in-process material and contact between concrete and concrete as building contact material. The impact sensitivity was higher for material with higher hardness for all building and in-process contact materials. Brass and wood is suggested to be used as process and building materials in order to reduce the risk of explosions due to impact sensitivity.

Thermal and Impact Sensitivity of Pyrotechnic Compositions Containing the Potassium Perchlorate, Aluminium and Graphite

The research article aims to study the impact and thermal sensitivity of pyrotechnic compositions which contain potassium perchlorate (KClO4), aluminium (Al) and graphite (C). Simultaneous DSC-TGA (Differential Scanning Calorimetry and Thermogravimetric Analysis) were used for studying the thermal sensitivity, and BAM fall hammer was used for studying the impact sensitivity. The onset temperature of the exothermic reaction is between 521°C to 528°C for all the studied compositions. The lowest onset temperature of 521°C and limiting impact energy of 16.67 J were found for the composition containing 64% of potassium perchlorate (KClO4), 33% aluminium (Al) and 3% graphite (C). The highest exothermic energy of 936 J/g was released for pyrotechnic composition consisting of 72% potassium perchlorate (KClO4), 25% aluminium (Al) and 3% graphite (C), which is close to the exothermic energy release of 910 J/g for pyrotechnic composition consisting 64% potassium perchlorate (KClO4), 33% aluminium (Al) and 3% graphite (C). Potassium chloride (KCl) was generated after the exothermic reaction, which was confirmed from the endothermic peak at around 773°C.

A “Green” Primary Explosive: Design, Synthesis, and Testing

This account presents the synthesis and the characterization of triazine-tetrazine nitrogen heterocyclic compounds. Some compounds were characterized by NMR and IR spectroscopy, mass spectrometry, differential scanning calorimetry (DSC), and single-crystal X-ray diffraction. The physical and chemical properties were obtained by EXPLO5 v6.01, gas pycnometer, BAM Fallhammer, BAM Friction tester, and several detonation tests. The results show that the new metal-free polyazido compound 3,6-bis-[2-(4,6-diazido-1,3,5-triazin-2-yl)-diazenyl]-1,2,4,5-tetrazine (4) with high heat of formation (2820 kJ mol–1/6130.2 kJ kg–1) and excellent detonation velocity and pressure (D = 8602 m s–1, P = 29.4 GPa) could be used as ingredient in secondary explosives. 3,6-Bis-[2-(4,6-diazido-1,3,5-triazin-2-yl)-hydrazinyl]-1,2,4,5-tetrazine (3) can detonate research department explosive (RDX, cyclonite) as a primer (Δf H m = 2114 kJ mol–1/4555.2 kJ kg–1, D = 8365 m s–1, P = 26.8 GPa), whose initiation capacity is comparable to that of the traditional primary explosive Pb(N3)2. Therefore, the metal-free compound 3 can potentially replace lead-based-primary explosives, which would be advantageous for the environment. 1 Introduction 2 Strategies to Form High-Nitrogen Compounds with High Heat of Formation 3 Metal-Free Strategies to Prepare Primary Explosives 4 Concluding Remarks

A “Green” Primary Explosive: Design, Synthesis, and Testing

This account presents the synthesis and the characterization of triazine-tetrazine nitrogen heterocyclic compounds. Some compounds were characterized by NMR and IR spectroscopy, mass spectrometry, differential scanning calorimetry (DSC), and single-crystal X-ray diffraction. The physical and chemical properties were obtained by EXPLO5 v6.01, gas pycnometer, BAM Fallhammer, BAM Friction tester, and several detonation tests. The results show that the new metal-free polyazido compound 3,6-bis-[2-(4,6-diazido-1,3,5-triazin-2-yl)-diazenyl]-1,2,4,5-tetrazine (4) with high heat of formation (2820 kJ mol–1/6130.2 kJ kg–1) and excellent detonation velocity and pressure (D = 8602 m s–1, P = 29.4 GPa) could be used as ingredient in secondary explosives. 3,6-Bis-[2-(4,6-diazido-1,3,5-triazin-2-yl)-hydrazinyl]-1,2,4,5-tetrazine (3) can detonate research department explosive (RDX, cyclonite) as a primer (Δf H m = 2114 kJ mol–1/4555.2 kJ kg–1, D = 8365 m s–1, P = 26.8 GPa), whose initiation capacity is comparable to that of the traditional primary explosive Pb(N3)2. Therefore, the metal-free compound 3 can potentially replace lead-based-primary explosives, which would be advantageous for the environment.1 Introduction2 Strategies to Form High-Nitrogen Compounds with High Heat of Formation3 Metal-Free Strategies to Prepare Primary Explosives4 Concluding Remarks

Size Reduction of HNS to Nanoscale by in Tandem Application of Chemo‐mechanical methods

AbstractThe present study was undertaken to evaluate and compare the extent of particle size reduction of HNS and its characterization by applying sequentially the solvent based crystallization, ultrasonication, and ball‐milling. It was found that submicron ultrafine HNS (UF‐HNS) of mean diameter ∼0.5 μm with a size range extending to micron scale (∼3 μm) was produced by the solvent‐antisolvent crystallization process. This HNS was subsequently subjected to long duration ultrasonication up to 28 h and planetary ball milling up to 8 h. The HNS particles were characterized for morphology and particle size by scanning electron microscope (SEM), laser diffraction‐based and dynamic light scattering based particle size analyzer (PSA). The structural analysis was done by FTIR and thermal stability by the thermo‐gravimetric analyzer (TGA). The residual solvent content was estimated by headspace GC‐MS. Impact and friction sensitivity were evaluated by BAM fall hammer and friction sensitivity tester. Compared to ultrasonication varying from 4 h to 28 h, planetary ball milling of the micron‐sized HNS caused the size reduction to maximum extent and resulted in production of nano‐scale HNS (∼300 nm average diameter) with a very narrow size distribution of less than 1 μm which had lower impact sensitivity, thermal stability and lesser residual solvent content compared to micron‐sized HNS (UF‐HNS). Thus, nanoscale HNS with a very narrow size distribution was produced by application of the mechanical method of ball milling sequentially to the solvent based crystallization process.

An Efficient Method of Preparation and Comprehensive Properties for Energetic Salts Based on Nitrofurazan‐Functionalized Hydroxytetrazoles

AbstractBased on the advantages of the furazan and tetrazole ring, the nitro and N‐oxide groups were introduced into furazan‐tetrazole backbone to four kinds of novel nitrofurazan‐functionalized hydroxytetrazole energetic salts. Various method have been employed to confirm their structures, such as multinuclear NMR, FTIR spectroscopy and elemental analysis. Salt guanidinium 5‐(4‐nitro‐furazan‐3‐yl)‐tetrazole‐1‐olate (5) and salt potassium 5‐(4‐hydroxyamino‐furazan‐3‐yl)‐tetrazole‐1‐olate (6) has been further elucidated by single‐crystal X‐ray diffraction. The non‐isothermal decomposition kinetics and thermodynamics for different salts were investigated by using TG‐DSC with different heating rate. The physico‐chemical properties and detonation performance were also studied and calculated by EXPLO5 program, in which salt hydroxylammonium 5‐(4‐nitro‐furazan‐3‐yl)‐tetrazole‐1‐olate (3) have a relatively high density of 1.839 g⋅cm−3 at 296 K and good detonation properties (vD = 9228 m⋅s‐1, P = 38.0 GPa), which is superior to that of RDX. The sensitivities towards impact and friction were also determined by BAM method (BAM Fallhammer Test for IS; BAM Friction Test for FS), in which the salt 5 showed very insensitive property (IS>60 J, FS>360 N) and can be comparable to that of TATB. Furthermore, the specific impulse of salt 3 (281 s) was even better than that of ammonium perchlorate (AP) (157 s) as neat compounds.

Investigation of Shear-Induced Exothermic Thermite Reaction in Al-Fe2O3 Epoxy Cast Composites

ABSTRACTThermite composites are lightweight and high-strength multifunctional energetic structural materials with a high reaction energy. In this study, the shear induced reaction of Al-Fe2O3-epoxy thermite composites using a modified BAM Fallhammer tester is investigated. The standard BAM Fallhammer tester is modified for better transport of impact energy under low velocity impact conditions. The mean Al particle size and the volume ratio of Al to Fe2O3 are varied using the factorial design of experiments to find their effect on the reactivity. From the experimental results, we observed that the epoxy binder increases the reaction sensitivity of the thermite mixture. Also, the composites containing smaller sized Al particles exhibit increased reaction sensitivity, whereas the sensitivity of the composites containing larger Al particles is higher in the fuel-rich (non-stoichiometric) composition compared to the stoichiometric composition.

Amination of Nitroazoles — A Comparative Study of Structural and Energetic Properties

In this work, 3-nitro-1H-1,2,4-triazole (1) and 3,5-dinitro-1H-pyrazole (2) were C-aminated and N-aminated using different amination agents, yielding their respective C-amino and N-amino products. All compounds were fully characterized by NMR (1H, 13C, 15N), IR spectroscopy, differential scanning calorimetry (DSC). X-ray crystallographic measurements were performed and delivered insight into structural characteristics as well as inter- and intramolecular interactions of the products. Their impact sensitivities were measured by using standard BAM fallhammer techniques and their explosive performances were computed using the EXPLO 5.05 program. A comparative study on the influence of those different amino substituents on the structural and energetic properties (such as density, stability, heat of formation, detonation performance) is presented. The results showed that the incorporation of an N-amino group into a nitroazole ring can improve nitrogen content, heat of formation and impact sensitivity, while the introduction of a C-amino group can enhance density, detonation velocity and pressure. The potential of N-amino and C-amino moieties for the design of next generation energetic materials is explored.

Energetic salts based on nitroiminotetrazole-containing acetic acid

2-(5-Nitroiminotetrazol-1-yl)acetic acid (4) was synthesized from 100% nitric acid and ethyl 2-(5-aminotetrazol-1-yl)acetate (2), which was easily obtained by reaction of ethyl aminoacetate hydrochloride, sodium hydroxide, and cyanogen azide. Compound 4 was also formed with 100% nitric acid and 2-(5-aminotetrazol-1-yl)acetic acid which was prepared from sodium 5-aminotetrazolate and 2-chloroacetic acid. New energetic materials comprised of nitroiminotetrazolate salts with nitroiminotetrazolate and carboxylate anions have been characterized spectroscopically as well as with single crystal X-ray diffraction and elemental analyses. In addition, the heats of formation (ΔHf), and detonation pressures (P) and velocities (D) were calculated. All compounds were insensitive (>40 J) for impact with BAM Fallhammer.