Synthesis,Characterization, and Energetic Properties of 6‐Amino‐tetrazolo[1,5‐b]‐1,2,4,5‐tetrazine‐7‐N‐oxide: A Nitrogen‐Rich Material with High Density

The synthesis and energetic properties of a novel N‐oxide high‐nitrogen compound, 6‐amino‐tetrazolo[1,5‐b]‐1,2,4,5‐tetrazine‐7‐N‐oxide, are described. Resulting from the N‐oxide and fused rings system, this molecule exhibits high density, excellent detonation properties, and acceptable impact and friction sensitivities, which suggests potential applications as an energetic material. Compared to known high‐nitrogen compounds, such as 3,6‐diazido‐1,2,4,5‐tetrazine (DiAT), 2,4,6‐tri(azido)‐1,3,5‐triazine (TAT), and 4,4′,6,6′‐tetra(azido)azo‐1,3,5‐triazine (TAAT), a marked performance and stability increase is seen. This supports the superior qualities of this new compound and the advantage of design strategy.     

The Pyridazine Scaffold as a Building Block for Energetic Materials: Synthesis,Characterization, and Properties

In the present studies, the synthesis of new energetic materials based on the pyridazine scaffold and their characterization is the main subject. For this purpose, desired 3,5‐dimethoxy‐4,6‐dinitropyridazine‐1‐oxide ( 7 ) was synthesized in the first instance. The persubstituted pyridazine precursor laid the groundwork for further preparative modification. The targeted functionalization through the regioselective introduction of various smaller amine nucleophiles such as methylamine or 2‐aminoethanol gave several new energetic materials. Among them are 3,5‐bis(methylamino)‐4,6‐dinitropyridazine‐1‐oxide ( 8 ), 3,5‐bis(methylnitramino)‐4,6‐dinitropyridazine‐1‐oxide ( 9 ), 3,5‐bis(dimethylamino)‐4,6‐dinitropyridazine‐1‐oxide ( 10 ), and 3,5‐bis((2‐hydroxyethyl)amino)‐4,6‐dinitropyridazine‐1‐oxide ( 11 ). With the aim of increasing the detonation performance, compound 8 was additionally nitrated and 3,5‐bis(methylnitramino)‐4,6‐dinitropyridazine‐1‐oxide ( 9 ) was obtained. These new energetic materials were characterized and identified by multinuclear NMR (¹H, ¹³C, ¹⁴N, ¹⁵N) and IR spectroscopy, elemental analysis and mass spectrometry. In addition, their sensitivities toward impact, friction and electrostatic discharge were thoroughly examined. Furthermore, obtained single‐crystals of the substances were characterized by low‐temperature single‐crystal X‐ray diffraction.     

1,1′‐Nitramino‐5,5′‐bitetrazoles

1,1′‐Dinitramino‐5,5′‐bitetrazole and 1,1′‐dinitramino‐5,5′‐azobitetrazole were synthesized for the first time. The neutral compounds are extremely sensitive and powerful explosives. Selected nitrogen‐rich salts were prepared to adjust sensitivity and performance values. The compounds were characterized by low‐temperature X‐ray diffraction, IR and Raman spectroscopy, multinuclear NMR spectroscopy, elemental analysis, and DTA/DSC. Calculated energetic performances using the EXPLO5 code based on calculated (CBS‐4M) heats of formation and X‐ray densities support the high performances of the 1,1′‐dinitramino‐5,5′‐bitetrazoles as energetic materials. The sensitivities toward impact, friction, and electrostatic discharge were also explored. Most of the compounds show sensitivities in the range of primary explosives and should only be handled with great care!     

2,4,6‐Trinitrotoluene – A Useful Starting Compound in the Synthesis of Modern Energetic Compounds

This review presents history, properties, and environmental fate of 2,4,6‐trinitrotoluene (TNT). Industrial methods of TNT production are discussed, as are several energetic derivatives of TNT. The performances and applications of these TNT derivatives are also described.     

Energetic Salts Based on Furazan‐Functionalized Tetrazoles: Routes to Boost Energy

Based on the backbone of the furazan‐tetrazole structure, routes were developed to improve the properties of energetic materials. Two types of high‐density energetic salts were designed, prepared, and fully characterized. Single‐crystal X‐ray analyses support the structural characteristics for two amino salts. A majority of the salts exhibited good detonation properties, high thermal stabilities, and relatively low impact and friction sensitivities. Hydroxylammonium and hydrazinium salts, 1 – 3 and 1 – 4 , which have relatively high densities (1.84 and 1.74 g cm^?3,, respectively), acceptable impact and friction sensitivities (14 J, 160 N and 28 J, 360 N), and good detonation pressures (38.3 and 32.2 GPa) and velocities (9323 and 9094 m s^?1), have performance properties superior to 1,3,5‐trinitro‐1,3,5‐triazinane (RDX) and triaminotrinitrobenzene (TATB).     

1,5‐Di(nitramino)tetrazole: High Sensitivity and Superior Explosive Performance

Highly energetic 1,5‐di(nitramino)tetrazole and its salts were synthesized. The neutral compound is very sensitive and one of the most powerful non‐nuclear explosives to date. Selected nitrogen‐rich and metal salts were prepared. The potassium salt can be used as a sensitizer in place of tetracene. The obtained compounds were characterized by low‐temperature X‐ray diffraction, IR and Raman spectroscopy, multinuclear NMR spectroscopy, elemental analysis, and DSC. Calculated energetic performances using the EXPLO5 code based on calculated (CBS‐4M) heats of formation and X‐ray densities support the high energetic performances of the 1,5‐dinitraminotetrazolates as energetic materials. The sensitivities towards impact, friction, and electrostatic discharge were also explored.     

[Mn(AZT)_2(H_2O)_4](HTNR)_2·4H_2O的合成、晶体结构、热行为及感度性质(英文)

通过酸性2,4,6-三硝基间苯二酚(HTNR)的锰盐与3-叠氮-1,2,4-三唑(AZT)在水溶液中反应,制备得到一种新颖的锰配合物[Mn(AZT)2(H2O)4](HTNR)2·4H2O.通过元素分析和红外光谱对配合物进行了表征,用X射线单晶衍射分析确定其晶体结构.该配合物为三斜晶系,空间群为P1,中心锰(Ⅱ)离子为六配位的畸变的八面体结构,分子内和分子间强烈的氢键作用构成了有序的三维(3D)网状结构.采用差示扫描量热(DSC)和热重-微分热重(TG-DTG)分析技术研究了配合物的热分解特性,并预测了它的热分解反应机理.利用Kissinger方法和Ozawa-Doyle方法研究了其第一放热分解峰的分解动力学过程.其分解过程包括一个吸热峰和三个放热峰,在600℃的分解产物为MnO和MnO2的混合物.同时.对这个配合物进行了感度(撞击感度、火焰感度、摩擦感度)性能分析,结果表明,它对外界刺激具有很强的响应性和选择性.     

A Hyper‐conjugated Structure: The Research into the Picryl Chloride Functionalized 1‐Picrylamino‐tetrazol‐5‐one

A hyper conjugated structure, picryl chloride functionalized 1‐picrylamino‐tetrazol‐5‐one, was synthesized by a nucleophilic substitution reaction. The single crystals of 1‐picrylamino‐tetrazol‐5‐one were cultured and determined by X‐ray single‐crystal diffractometer. The thermal behavior was investigated by differential scanning calorimetry (DSC) and thermogravimetry‐derivative thermogravimetry (TG‐DTG) technologies. Additionally, the sensitivities towards friction and impact were tested. The results show that the hyper conjugated structure adopts a π–π stacking, besides, many strong interactions such as nitro–π and hydrogen bonding interactions were observed. All of them together make a contribution to its enhanced thermal stability and reduced sensitivities. 1‐Picrylamino‐tetrazol‐5‐one turns out to be a representative of hyper conjugated structures in energetic materials, and may further strengthen the functionalization of picryl chloride with energetic tetrazoles.     

3,4,5‐Trinitropyrazole‐Based Energetic Salts

High‐density energetic salts that are comprised of nitrogen‐rich cations and the 3,4,5‐trinitropyrazolate anion were synthesized in high yield by neutralization or metathesis reactions. The resulting salts were fully characterized by ¹H, ¹³C NMR, and IR spectroscopy; differential scanning calorimetry; and elemental analysis. Additionally, the structures of the 3,5‐diaminotriazolium and triaminoguanidinium 3,4,5‐trinitropyrazolates were confirmed by single‐crystal X‐ray diffraction. Based on the measured densities and calculated heats of formation, the detonation performances (pressure: 23.74–31.89 GPa; velocity: 7586–8543 ms^?1; Cheetah 5.0) of the 3,4,5‐trinitropyrazolate salts are comparable with 1,3,5‐triamino‐2,4,6‐trinitrobenzene (TATB; 31.15 GPa and 8114 ms^?1). Impact sensitivities were determined to be no less than 35 J by hammer tests, which places these salts in the insensitive class.     

A Study of the 3,3,3‐Trinitropropyl Unit as a Potential Energetic Building Block

Compared with the well‐established 2,2,2‐trinitroethyl group in the chemistry of energetic materials, the 3,3,3‐trinitropropyl group is less investigated regarding its chemical and energetic properties. Thus, investigations on the syntheses of several compounds containing the 3,3,3‐trinitropropyl group were performed and their properties compared with the 2,2,2‐trinitroethyl group. All materials were thoroughly characterized, including single‐crystal X‐ray diffraction studies. The thermal stabilities were examined using differential thermal analysis (DSC) and the sensitivities towards impact, friction, and electrostatic discharge were tested using a drop hammer, a friction tester, and an electrical discharge device. The energies of formation were calculated and several detonation parameters such as the velocity of detonation and the propulsion performance were estimated with the program package EXPLO5.     

New Correlation between Electric Spark and Impact Sensitivities of Nitramine Energetic Compounds for Assessment of Their Safety

Electric spark and impact sensitivities of nitramine energetic compounds are two important sensitivity parameters, which are closely related to many accidents in working places. For nitramines, in contrast to electric spark sensitivity, their impact sensitivity can be easily measured or predicted by various methods. A new approach is introduced to correlate electric spark and impact sensitivities of nitramine energetic compounds by the use of three structural parameters. The predicted results of the novel model for 20 nitramines are compared with two of the best available models, which are based on complex quantum mechanical approach and the measured values of activation energies of thermolysis. The root‐mean‐square (rms) and maximum deviations of the new model are 1.06 and 2.41 J, respectively. For further 14 nitramines, where the measured electric spark or impact sensitivities were not available, the estimated electric spark sensitivities by the new model are close to those predicted based on experimental data of activation energies of thermolysis.     

Synthesis and Investigation of 2,6‐Bis(picrylamino)‐3,5‐dinitro‐pyridine (PYX) and Its Salts

2,6‐Bis(picrylamino)pyridine ( 1 ; pre‐PYX) and 2,6‐bis(picrylamino)‐3,5‐dinitropyridine ( 2 ; PYX) were synthesized using an improved literature method. Compounds 1 and 2 were reinvestigated in detail and the X‐ray structures ( 1 : ρ=1.698 g cm^?3 at 173 K; 2 : ρ=1.757 g cm^?3 at 298 K) are given. The reactions of 2 with different bases, such as alkali metal hydroxides (sodium, potassium, rubidium, cesium), and N‐bases (ammonia, hydrazine, hydroxylamine, guanidinium carbonate, aminoguanidine bicarbonate) are reported, as well as metathesis reactions producing energetic salts. Several energetic compounds were synthesized and characterized for the first time using vibrational (IR, Raman) and multinuclear NMR spectroscopy, mass spectrometry, elemental analysis, and DSC. The crystal structures of four energetic salts were determined using low temperature single‐crystal X‐ray diffraction. Heats of formation for the metal‐free species were calculated using the Gaussian 09 software. Detonation parameters were estimated using the EXPLO5 program. The sensitivities towards impact, friction, and electrostatic discharge were also determined.     

3,6,7‐Triamino‐[1,2,4]triazolo[4,3‐b][1,2,4]triazole: A Non‐toxic,High‐Performance Energetic Building Block with Excellent Stability

A novel strategy for the design of energetic materials that uses fused amino‐substituted triazoles as energetic building blocks is presented. The 3,6,7‐triamino‐7H‐[1,2,4]triazolo[4,3‐b][1,2,4]triazolium (TATOT) motif can be incorporated into many ionic, nitrogen‐rich materials to form salts with advantages such as remarkably high stability towards physical or mechanical stimuli, excellent calculated detonation velocity, and toxicity low enough to qualify them as “green explosives”. Neutral TATOT can be synthesized in a convenient and inexpensive two‐step protocol in high yield. To demonstrate the superior properties of TATOT, 13 ionic derivatives were synthesized and their chemical‐ and physicochemical properties (e.g., sensitivities towards impact, friction and electrostatic discharge) were investigated extensively. Low toxicity was demonstrated for neutral TATOT and its nitrate salt. Both are insensitive towards impact and friction and the nitrate salt combines outstanding thermal stability (decomposition temperature=280 °C) with promising calculated energetic values.     

1-AminoTriazole Transition-Metal Complexes as Laser-Ignitable and Lead-Free Primary Explosives

This unique complex study describes two isomeric aminotriazoles as auspicious nitrogen-rich ligands for energetic coordination compounds (ECCs) to replace the commonly used highly poisonous and environmentally harmful lead-based primary explosives. The triazoles were obtained by easily scalable and convenient synthetic routes starting solely from commercially available starting materials. 1-Amino-1,2,3-triazole ( 1 , 1-ATRI) and, for the first time, 1-amino-1,2,4-triazole ( 2 , 1A-1,2,4-TRI) were employed as ligands to form highly energetic transition-metal(II) complexes. The desired characteristics could be altered successively by using various nonpoisonous metal(II) centers (Cu²⁺, Mn²⁺, Fe²⁺, and Zn²⁺) and anions (Cl⁻, NO₃⁻, ClO₃⁻, ClO₄⁻, picrate, styphnate, 2,4,6-trinitro-3-hydroxyphenolate, and 2,4,6-trinitro-3,5-dihydroxyphenolate). The 14 synthesized coordination compounds were characterized comprehensively by XRD, IR and UV/Vis spectroscopy, elemental analysis, and differential thermal and thermogravimetric analyses. Ball-drop impact, electrostatic discharge (ESD), and mechanical (impact and friction) sensitivities were determined according to BAM standard methods. In addition to laser ignition experiments, selected ECCs were evaluated in classical secondary explosive initiation tests (detonators filled with pentaerythritol tetranitrate (nitropenta)), which revealed their enormous potential and proved them to be very attractive for future applications in explosives.     

Energetic Salts Based on an Oxygen‐Containing Cation: 2,4‐Diamino‐1,3,5‐triazine‐6‐one

A family of energetic salts with high thermal stability and low impact sensitivity based on an oxygen‐containing cation, 2,4‐diamino‐1,3,5‐triazine‐6‐one, were synthesized and fully characterized by IR and multinuclear (¹H, ¹³C) NMR spectroscopy, elemental analysis, and differential scanning calorimetry. Insights into their sensitivities towards impact, friction, and electrostatics were gained by submitting the materials to standard tests. The structures of 2,4‐diamino‐1,3,5‐triazine‐6‐one nitrate, 2,4‐diamino‐1,3,5‐triazine‐6‐one sulfate, 2,4‐diamino‐1,3,5‐triazine‐6‐one perchlorate, 2,4‐diamino‐1,3,5‐triazine‐6‐one 5‐nitrotetrazolate were determined by single‐crystal X‐ray diffraction; their densities are 1.691, 1.776, 1.854, and 1.636 g cm^?3, respectively. Most of the salts decompose at temperatures over 180 °C; in particular, the salts 2,4‐diamino‐1,3,5‐triazine‐6‐one nitrate and 2,4‐diamino‐1,3,5‐triazine‐6‐one perchlorate, which decompose at 303.3 and 336.4 °C, respectively, are fairly stable. Furthermore, most of the salts exhibit excellent impact sensitivities (>40 J), friction sensitivities (>360 N), and are insensitive to electrostatics. The measured densities of these energetic salts range from 1.64 to 2.01 g cm^?3. The detonation pressure values calculated for these salts range from 14.6 to 29.2 GPa, and the detonation velocities range from 6536 to 8275 m s^?1; these values make the salts potential candidates for thermally stable and insensitive energetic materials.     

Trimerization of 4‐Amino‐3,5‐dinitropyrazole: Formation,Preparation, and Characterization of 4‐Diazo‐3,5‐bis(4‐amino‐3,5‐dinitropyrazol‐1‐yl) pyrazole (LLM‐226)

4‐Amino‐3,5‐dinitropyrazole (LLM‐116, 1 ) undergoes trimerization to 4‐diazo‐3,5‐bis(4‐amino‐3,5‐dinitropyrazol‐1‐yl) pyrazole (LLM‐226) upon heating. A mechanism is proposed and discussed. LLM‐226 is a new diazo‐based energetic material, thermally stable, and insensitive to impact, friction, and spark. The material may be prepared by heating 1 and 4‐diazo‐3,5‐dinitropyrazole ( 2 ) in a mixture of toluene and butyl acetate at 110°C or heating 1 alone in dichlorobenzene at 160°C. The characterization of LLM‐226 including X‐ray crystallographic analysis and small‐scale safety properties will be discussed.     

Preparation,Crystal Structure,and Thermal Analysis of Two Energetic Salts Based on Nitro Phenolic Compounds with Diamino‐glyoxine

As a key research objective for environmentally friendly energetic materials, energetic salts without heavy metal have received wide attention. The energetic salts DAG · PA · H₂O ( 1 ) and DAG · TNR · H₂O ( 2 ) were synthesized by using diamino‐glyoxine (DAG) and picric acid (PA) or 2, 4,6‐trinitro‐resorcinol (TNR) as raw materials, and their structures were characterized by elemental analysis, FT‐IR, ¹H NMR, and ¹³C NMR spectroscopy. Single crystals of the title salts were cultured and their structures were determined by X‐ray single‐crystal diffraction. Both salts belong to the triclinic space group P1 with density values of 1.764 and 1.751 g · cm^–3, respectively. The thermal decomposition behaviors of both salts were investigated by differential scanning calorimetry (DSC), the non‐isothermal kinetic parameters and the critical temperature of thermal explosion were calculated. The heats of formation for the salts were also determined through the combustion heats date measured by using the oxygen bomb calorimetry. In addition, the detonation pressure (P) and detonation velocities (D) of the salts were predicted by using the K‐J equations, and their sensitivities towards impact and friction were tested. The results indicated that the title salts have potential applications in the field of energetic materials.     

Multiply Nitrated High‐Energy Dense Oxidizers Derived from the Simple Amino Acid Glycine

Various energetic polynitro esters, carbamates, and nitrocarbamates that were derived from the amino acid glycine were fully characterized by single‐crystal X‐ray diffraction, vibrational spectroscopy (IR and Raman), multinuclear NMR spectroscopy, elemental analysis, and differential scanning calorimetry (DSC). Owing to their positive oxygen balance, the suitability of these compounds as potential oxidizers in energetic formulations was investigated and discussed. In addition, the heats of formation of the products were calculated by using the Gaussian 09 program package at the CBS‐4M level of theory. From these values and the calculated densities (from the X‐ray data), several detonation parameters, such as detonation pressure, velocity, energy, and temperature, were computed by using the EXPLO5 code. Furthermore, their sensitivities towards impact, friction, and electrostatic discharge were tested by using a drop hammer, a friction tester (both BAM certified), and a small‐scale electrical‐discharge device, respectively.     

Liquid chromatography/negative ion atmospheric pressure photoionization mass spectrometry: a highly sensitive method for the analysis of organic explosives

Gas chromatography/mass spectrometry (GC/MS) is applied to the analysis of volatile and thermally stable compounds, while liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (LC/APCI‐MS) and liquid chromatography/electrospray ionization mass spectrometry (LC/ESI‐MS) are preferred for the analysis of compounds with solution acid‐base chemistry. Because organic explosives are compounds with low polarity and some of them are thermally labile, they have not been very well analyzed by GC/MS, LC/APCI‐MS and LC/ESI‐MS. Herein, we demonstrate liquid chromatography/negative ion atmospheric pressure photoionization mass spectrometry (LC/NI‐APPI‐MS) as a novel and highly sensitive method for their analysis. Using LC/NI‐APPI‐MS, limits of quantification (LOQs) of nitroaromatics and nitramines down to the middle pg range have been achieved in full MS scan mode, which are approximately one order to two orders magnitude lower than those previously reported using GC/MS or LC/APCI‐MS. The calibration dynamic ranges achieved by LC/NI‐APPI‐MS are also wider than those using GC/MS and LC/APCI‐MS. The reproducibility of LC/NI‐APPI‐MS is also very reliable, with the intraday and interday variabilities by coefficient of variation (CV) of 0.2–3.4% and 0.6–1.9% for 2,4,6‐trinitrotoluene (2,4,6‐TNT). Copyright © 2008 John Wiley & Sons, Ltd.     

A New Energetic Material and its Risk Research

Bis (1, 5‐diamino‐4‐methyl‐tetrazolium) azotetrazolate ( BMDATZT ) was synthesized with high yield in this work. The yield is 97.46%. The structure was characterized by IR, ¹H NMR, and MS. The single crystal of BMDATZT?2H₂O was first cultivated. The heat of formation, detonation pressure, and detonation velocity were first calculated. The crystalline density of BMDATZT?2H₂O is 1.573 g/cm³. BMDATZT has high detonation pressure and detonation velocity (P =25.06 GPa, D = 7.805 km s^?1), which are higher than those of 2,4,6‐Trinitrotoluene (TNT). Its thermal and mechanical sensitivities are moderate. Therefore, it is a kind of insensitive nitrogen‐rich energetic ionic salt with good performance, and it has potential application prospect in gas generating agent, explosive and solid propellant.