Abstract:

Abstract:

Abstract:3， 4-bis（3-cyanofurazan） furazan oxide（BCTFO） was synthesized from 3， 4-dicyanofurazan as raw material by multistep functional group transformation of cyanide. The structure of BCTFO was characterized by IR， ¹³C and ¹⁵N NMR and elemental analysis. Combined with the theoretical simulation of GIAO method， the attribution of ¹³C NMR and ¹⁵N NMR spectra was completed. The single crystal of BCTFO was cultivated for the first time， which belongs to monoclinic， C2/c space group. The unit cell parameters are a=19.742（4） Å， b=8.851（2） Å， c=29.275（7） Å，V=4951.3（19） ų，Z=8， ρ=1.75 g·cm^-3， F（000）=2600， S=1.043， R₁=0.0491， wR₂=0.1375. Based on the determined density （ρ=1.76 g·cm^-3） and calculated enthalpy of formation （Δ_fH（s）=806.7 kJ∙mol^-3）， the detonation velocity （D） and detonation pressure （P） of the BCTFO are estimated to be 8086 m·s^-1 and 27.3 GPa by using Explo5（V6.04）. Differential scanning calorimetry （DSC） and thermogravimetric analyzer （TG） were used to study the thermal decomposition process of BCTFO. The peak temperature of thermal decomposition was T_dec=235.4 ℃. The sensitivity of BCTFO was measured according to BAM standard method， the impact sensitivity is 16 J and the friction sensitivity is 330 N.

Abstract:Using 4，5-dicyano-2-aminoimidazole as raw material， 4，5-Bis-（chloro-dinitro-methyl）-2-diazoimidazole was prepared through three-step reactions of oximation， chlorination， diazotization. The structure was characterized by X-ray single crystal diffraction analysis， Fourier transform infrared spectroscopy（FT-IR）， nuclear magnetic resonance spectroscopy （1H NMR， 13C NMR） and high resolution mass spectrometry（HRMS）. The thermal properties were studied by differential scanning calorimeter and thermogravimetric analyzer. Its structure was optimized using Gaussian09 and its performance was estimated using Explo5 v6.01.. The results show that the crystal of 4，5-Bis-（chloro-dinitro-methyl）-2-diazoimidazole belongs to the triclinic P1 space group. The unit cell parameters are a=6.6196 （10） Å， b=8.1685（13） Å， c=13.0272（19） Å， V=666.96（18） Å， α=100.166（4）°，β=102.560（4）°， γ=97.153（5）°， Z=2， F（000）=368； D_c=1.848 g·cm^-3. Its thermal decomposition temperature is 122.14 ℃.The theoretical detonation velocity is 8574 m·s^-1 and the theoretical detonation pressure is 32.8 GPa. According to the BAM standard method， the impact sensitivity is 4 J and the friction sensitivity is 100 N.

Abstract:2，4，8，10-Tetranitro-benzopyrido-1，3a，6，6a-tetraazapentalene （NBTTP） was synthesized from 1H-benzotriazole and 2-chloro-3-nitropyridine via displacement， cyclization and nitration.The structure of NBTTP was characterized by FTIR and NMR. In addition， the reaction condition of cyclization was optimized. Its thermalbehavior was analyzed by TG-DTG， while its thermal decomposition behavior， kinetic parameters and thermodynamic parameters were obtained by DSC. The results shows that the highest yield was up to 83.44%， when the molar ratio of triethylphosphite and the BTP was 3∶1. NBTTP presents a main single exothermal event with initial at around 388.79 ℃ and maximum at around 406.23 ℃. Its non-isothermal kinetics equations of thermal decomposition may be described as dα/dt=（6.36×10¹⁴/β）（1-α）exp［-2.34×10⁵/（RT）］. The entropy （ΔS^≠）， enthalpy （ΔH^≠）， free energy （ΔG^≠） and self-accelerating decomposition temperature （T_SADT） were 23.60 J·mol^-1·K^-1， 228.97 kJ·mol^-1， 213.46 kJ·mol^-1 and 655.11 K， respectively.

Abstract:4-hydroxy-3，5-dinitropyrazole（H-DNOP， 2） was synthesized from 3，5-dinitro4-bromopyrazole（1） by hydrolysis and neutralization reaction. Three kinds of ionic energetic compounds （3-5） of DNOP were designed and synthesized by using its acidity. The structures of compounds 3-5 were characterized by FT-IR， NMR spectrum， elemental analysis as well as single-crystal X-ray diffraction， and their thermal stabilities were investigated by differential scanning calorimetry and thermogravimetry （DSC-TG）. The maximum decomposition temperature of hydrazine salt （3） was T_d=210.3 ℃. The impact sensitivity and friction sensitivity were measured by BAM method， while the detonation parameters were predicted based on the isodesmic reactions and the Kamlet-Jacobs equation. The results show that the measured impact sensitivity and friction sensitivity of the threecompounds 3-5 are all 36 J and 360 N， which are less sensitive than those of TNT（IS=15 J，FS=353 N） and RDX（IS=7.4 J，FS=120 N）. The theoretical detonation velocities of the three compounds are 7758-8288 m·s^-1， and the detonation pressures are 26.06-29.96 GPa， respectively.

Abstract:Planar heteroaromatic compounds containing amino and nitro functional groups usually have excellent detonation performances. Hereby， the ─NH─ bond bridging two high-nitrogen fused rings was adopted aiming at constructing a nitrogen-rich energetic compound with a planar structure. The resulting compound is expected to have a regular packing in crystal and favorable detonation performance and stabilities. Reaction of 2，6-diamino-3，5-dinitropyrazine （2） with K₂CO₃ gives rise to 6-（2，6-diamino-3，5-dinitropyrazine）-1，2，4-triazole［4，3-b］［1，2，4，5］tetrazine （3） in a high yield of 81.3%. Compound 3 was characterized by NMR， IR， single crystal X-ray diffraction. The thermal decomposition process of 3 was studied by differential scanning calorimetry （DSC）， and its decomposition temperature （onset） is as high as 254.6 ℃. The detonation performances of 3 （D=7568 m·s^-1， P=23.5 GPa） were calculated by Gaussian 09 and Explo5 software.

Abstract:In order to obtain energetic materials with excellent performance， a new type of energetic ionic salt 4-hydroxy-3，5-dinitropyrazole guanidine salt （DNPOG） was synthesized by nitration， hydrolysis， acidification and salt formation reaction with 4-chloropyrazole as raw material. The structure was characterized by FTIR， NMR and EA analysis. The crystal structure of DNPOG was triclinic with space group P-1， relative molecular mass M_r=233.17 g·cm^-1， a=4.8958（5） Å， b=8.1933（8） Å， c=11.9669（11） Å， Z=2， and crystal density D_c=1.750 g·cm^-3. The contribution of hydrogen bond and π-π conjugation in DNPOG to the intermolecular interaction force was calculated and studied， and the hydrogen bond accounted for 47%. The thermal decomposition characteristics were investigated by differential scanning calorimetry （DSC） and thermogravimetry （TG）. The peak temperature of the first decomposition was 212.5 ℃. The detonation and safety properties of DNPOG were studied. The detonation velocity is 7871 m·s^-1， the detonation pressure is 23.8 GPa， the formation enthalpy is -160.2 kJ·mol^-1， the impact sensitivity is 20 J， and the friction sensitivity is 240 N. The results show that DNPOG is layered accumulation， with good thermal stability and low sensitivity， which is a kind of low sensitivity explosive with excellent performance.

Abstract:Using 1，4-dihydrazide succinate as raw material， 1，2-bis（3，3"-dinitroamine-1H-1，2，4-triazol-5-yl）ethane monohydrate （1） was synthesized by the one-pot “MNNG ring method”. And the synthetic conditions of this reaction were carefully optimized. The corresponding 1，3-propanediamine salt （2） was obtained through the reaction of compound 1 and 1，3-propanediamine. The detailed single crystal structure of compound 2 was determined by X-ray single crystal diffraction. FT-IR， NMR and elementary analysis were used to characterize the structures of compounds 1 and 2. Moreover， the thermal properties of compounds 1 and 2 have been studied by TG-DSC. The results showed that the initial decomposition temperature of compounds 1 and 2 are 184 ℃ and 214 ℃， respectively. The main detonation parameters of compounds 1 and 2 were calculated by using EXPLO5 （v6.02） software. The calculated detonation velocity of compound 1 is 8602 m·s^-1 and its calculated detonation pressure is 28.10 GPa. For compound 2， the calculated detonation velocity and detonation pressure are 7740 m·s^-1 and 19.10 GPa， respectively. Furthermore， their mechanical sensitivities were tested by BAM sensitivity test. The impact sensitivity of compound 1 is 35 J and its friction sensitivity is 108 N. The impact sensitivity of compound 2 is greater than 40 J， and its friction sensitivity is more than 360 N.

Abstract:The azo functionality is not only a bridging block， but also can generally increase the density and heat of formation of energetic nitrogen-rich heterocycles. Therefore， building new energetic materials through the bridging method has gradually become a research hotspot in this field. This article reviewed synthesis method， physical and chemical properties and detonation properties of azo-bridged nitrogen-rich heterocycles focusing on azoles and azines from C—NH₂ and N—NH₂ oxidative couplings. This review will provide some references for the research and development of new azo-bridged nitrogen-rich heterocycles.

Abstract:Gem-dinitro group is an attracting moiety in designing novel high energy density compounds due to their high density and oxygen content comparing to the nitro group. The planar structure of gem-dinitro group is beneficial to improve the density， oxygen balance and detonation properties when cooperating with nitrogen-rich heterocycles. In this review， the method of preparing gem-dinitro salts from different precursors was listed， the advantages of using N₂O₄ or N₂O₅ or mixed acid as the nitration agent to prepare gem-dinitro compounds and their scopes of application were summarized， their energetic characteristics were discussed. It is hoped that this review could provide reference for the design and synthesis of new high-energy insensitive energetic materials.

Abstract:Dichloroglyoxime is an efficient industrial bactericide and an important starting material for construction of nitrogen heterocyclic framework， which can be utilized as a pivotal precursor for a variety of high nitrogen energetic materials with excellent performances. Three synthetic methods of dichloroglyoxime， such as chlorine method， NCS/DMF method and NCS/DMF improved method， were introduced， and their advantages and disadvantages were also discussed. Based on the reaction characteristics of dichloroglyoxime， the methods of constructing N-heterocyclic frameworks， such as isoxazole，furoxan， furoxan， bistetrazole and oxadiazolone， were systematically described. Additionally， the physicochemical properties and detonation performances of typical energetic materials were also discussed. Using dichloroglyoxime as starting materials， it is expected to design and synthesize some new energetic materials with excellent performances，and comprehensively promote the innovation ability of energetic materials.