Synthesis and Properties of 3,6‐Dinitropyrazolo[4,3‐c]‐pyrazole (DNPP) Derivatives

Abstract

A series of novel fused‐ring pyrazolo[4,3‐c]pyrazole derivatives featuring N‐dinitromethyl and N‐fluorodinitromethyl energetic groups (compounds 3–7) were synthesized using a nine‐step reaction. All these compounds were characterized using multinuclear nuclear magnetic resonance (NMR) spectroscopy, infra‐red (IR) spectroscopy, and elemental analysis. X‐ray diffraction analysis was performed, and the single‐crystal structures of compounds 3, 4, 6, and 7 were obtained. For these newly prepared energetic materials, the thermal stability was determined using differential scanning calorimetry (DSC), while the sensitivities were evaluated using BAM drop hammer and friction test. The calculated heat of formation values and the measured densities were used to determine the detonation parameters, including detonation velocity and pressure, using the EXPLO5 program. Of all the prepared compounds, dipotassium 1,4‐bis(dinitromethyl)‐3,6‐dinitro‐1,4‐dihydropyrazolo[4,3‐c]pyrazole (3) was crystallized as a three‐dimensional energetic metal‐organic framework (MOF) and showed outstanding detonation performances, which even outperformed the traditional primary explosive lead azide. Compound 7 exhibited a high crystal density of 1.939 g cm−3, the high decomposition temperature of 213 °C and desirable impact and friction sensitivities (IS: 12 J; FS: 240 N). These combined properties and performances make these novel fused‐ring energetic compounds suitable candidates for high‐performance energetic materials.

Continuous Crystallization Process of Cefminox Sodium in MSMPR Crystallizer

“…Apelblat equation and CNIBS/R‐K equation were used to correlate the kinetic solubility of cefminox sodium in binary mixed solvents (water–ethanol, water–acetone). [ 27–30 ] Apelblat equation was shown in Equation (4): $$$$\begin{equation}\ln {x_{\rm{A}}} = A + \frac{B}{T} + C\ln T\end{equation}$$$$where x A is the molar fraction kinetic solubility of solute; A , B , C are model parameters, and T is absolute temperature. CNIBS/R‐K equation was shown in Equation (5): $$$$\begin{equation}\ln {x_{\rm{A}}} = {B_0} + {B_1}{f_{\rm{b}}} + {B_2}f_{\rm{b}}^2 + {B_3}f_{\rm{b}}^3 + {B_4}f_{\rm{b}}^4\end{equation}$$$$where f b is the molar fraction of water in binary mixed system, B 0 , B 1 , B 2 , B 3 , B 4 are the equation model parameter.…”

Recent Advances in Synthesis and Properties of Nitrated-Pyrazoles Based Energetic Compounds

“…In addition, Zhang et al [ 145 ] introduced the dinitromethyl group and fluorodinitromethyl group into DNPP molecule and synthesized five fused-ring energetic derivatives ( 131 – 132 ) shown in Figure 41 . Among these compounds, the dipotassium salt ( 131a ) was formed as an interesting three-dimensional metal-organic framework (MOF) and exhibited outstanding detonation performances (9.02 km·s −1 of D and 33.6 GPa of P ), which were comparable to that of Pd(N 3 ) 2 .…”

Synthesis, thermal behaviors, and energetic properties of asymmetrically substituted tetrazine-based energetic materials

“…For the purpose of gaining high energy while keeping good stability, high nitrogen content energetic materials (HNCEMs) were developed in the past few decades ( Lin et al, 2018 ; Tarchoun et al, 2020 ; Wu et al, 2020 ; Lei et al, 2021a ; Feng et al, 2021 ; Herweyer et al, 2021 ; Tang et al, 2021 ). The common HNCEMs are pyrazole ( Li et al, 2018 ; Zhang W. et al, 2020 ; Lei et al, 2021b ; Lai et al, 2022 ), triazole ( Manship et al, 2020 ; Wozniak et al, 2020 ; Yan et al, 2020 ), tetrazole ( Gamekkanda et al, 2020 ; Yu et al, 2019 ; Jafari et al, 2018 ), and tetrazine ( Chavez and Hiskey, 1999 ; Hiskey et al, 2001 ; Chavez et al, 2004 ; Gao et al, 2006 ; Sinditskii et al, 2012 ; Ma et al, 2021 ) heterocyclic compounds. Among them, tetrazine compounds have a high nitrogen content of 68.3%, and their skeleton shows good thermal stability and low mechanical sensitivity.…”