Jinglun Huang

A novel multi-nitrogen 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane-based energetic co-crystal with 1-methyl-3,4,5-trinitropyrazole as a donor: experimental and theoretical investigations of intermolecular interactions

A novel multi-nitrogen energetic cocrystal, 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL-20), with 1-methyl-3,4,5-trinitropyrazole (MTNP) as a donor, in a 1u2006:u20061 molar ratio was prepared and characterized by X-ray diffraction. Instead of traditional aromatic donors such as 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrobenzene (TNB), multi-nitrogen azole compound was introduced in this study. CL-20:MTNP has a high crystal density of 1.932 g cm−3 at 293(2) K and superior detonation performance (νD = 9347 m s−1, P = 40.5 GPa) due to its high heat of formation, nitrogen content, and oxygen balance. Moreover, measured impact and friction sensitivities (IS = 6 J, FS = 180 N) show that it is more insensitive than CL-20, close to those of RDX and HMX. To analyze the intermolecular interaction of CL-20:MTNP, a series of theoretical analyses was employed including Hirshfeld surface analysis, non-covalent interaction plots, interaction energy calculations, and electrostatic surface potential distributions. The physicochemical performance implies that CL-20:MTNP can serve as a promising energetic material, and the methyl-substituted low-point explosives, acting as donor–acceptor, can be a new strategy for constructing a series of novel multi-nitrogen energetic cocrystals towards future high-performance energetic materials.

5,6-Di(2-fluoro-2,2-dinitroethoxy)furazano[3,4- b ]pyrazine: a high performance melt-cast energetic material and its polycrystalline properties

5,6-Di(2-fluoro-2,2-dinitroethoxy)furazano[3,4-b]pyrazine was synthesized in a three-step process starting from 3,4-diaminofurazan (DAF) including a significant nucleophilic substitution reaction under the catalytic effect of trisodium phosphate dodecahydrate. Characterization of this molecule indicates that it possesses a higher crystal density than that of 2,4,6-trinitrotoluene (TNT) at ambient temperature with acceptable melting-point and energetic properties approaching those of 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) but with a higher thermal stability and lower sensitivity towards impact and friction. To investigate its polycrystalline properties, differential scanning calorimetry (DSC), powder-X-ray-diffraction (PXRD) and ab initio calculation using the Viena Ab initio simulation package (VASP) were employed.

Synthesis and thermal decomposition performance of 3,6,7-triamino-7H-s-triazolo[5,1-c]-s-triazole

Abstract3,6,7-Triamino-7H-s-triazolo[5,1-c]-s-triazole was synthesized from triaminoguanidine hydrochloride and cyanogen bromide, and has been prepared at the 30-g scale. A single crystal of 3,6,7-triamino-7H-s-triazolo[5,1-c]-s-triazole was cultivated, and its crystalline density at 293xa0K was 1.726xa0gxa0cm−3. Its heat of formation (ΔHf,solidxa0=xa0470.5xa0kJxa0mol−1) was computed by using thexa0density functional theoryxa0(DFT) method, and its detonation pressure and detonation velocity were further predicted by EXPLO5 code (Dxa0=xa09483xa0mxa0s−1, Pxa0=xa030.4xa0GPa). The intermolecular interaction of the title compound was investigated by Hirshfeld surface analysis. Moreover, its thermodynamic performance was evaluated by non-isothermal kinetic methods based on the results of the differential scanning calorimeter (DSC), which shows that thexa0apparent activation energy (Ea) obtained by Kissinger, Ozawa and Starink methods is 223.55, 221.61 and 223.73xa0kJxa0mol−1, respectively. Meanwhile, the transformation of molecular structure was analyzed by the rapid scanning Fourier transform infrared spectroscopy (RSFT-IR) under the temperature range from 50 to 300xa0°C. The reaction pathway was further supported by quantum chemical calculations. 3,6,7-Triamino-7H-s-triazolo[5,1-c]-s-triazole processes good vacuum thermal stability, high detonation performance and low sensitivity. It is convincible that these physical–chemical properties make 3,6,7-triamino-7H-s-triazolo[5,1-c]-s-triazole a promising candidate worthy of further investigation.

Construction of New Insensitive Explosives: Fused N5-Chain N1,N3,N5-(1,2,3,4-Tetrazole -5-Nitro)-1,3,5-Triamino-2,4,6-Trinitrobenzene Derivatives

A series of N1,N3,N5-(1,2,3,4-tetrazole-5-nitro)-1,3,5-triamino-2,4,6-trinitrobenzene derivatives containing fused N5-chain were investigated theoretically. Density functional theory has been employed to calculate their geometric, electronic structures, band gaps, and heats of formation at the B3LYP/6-31G** level. The detonation performance was evaluated by using Kamlet-Jacobs equations based on the calculated densities and HOFs. The thermal stability of these compounds was investigated by bond dissociation energies, energy gaps and molecular electrostatic potentials. Results show that there are good linear relationships between detonation velocity, detonation pressure and the number of nitro groups. Most of the designed derivatives have higher detonation velocity (D), detonation pressure (P), and specific impulse (Isp) than those of RDX. D and Isp of molecule L even outperform those of CL-20. Some of the title molecules have higher h50 (impact sensitivity) than RDX (except for D, H, L). According to the quantitative standard of energy and stability as insensitive high energetic materials (IHEMs), molecules I and J essentially satisfy this requirement. These results provide basic information for molecules design of novel IHEMs.

Theoretical Screening of Novel 5-picrylamino- 1,2,3,4-tetrazole (PAT) and 5,5′-styphnylamino-1,2,3,4-tetrazole (SAT) Derivatives: A New Molecular Design Strategy of Multi-Nitrogen Energetic Materials by Introducing Intermolecular Hydrogen Bonds and π–π Stacking Interactions

ABSTRACT On the basis of a design strategy that results in the introduction of intramolecular hydrogen-bonds and π–π stacking interactions leading to low-sensitive and high-energy materials (LSHMs), –NH2/–NO2 fused derivatives of 5-picrylamino- 1,2,3,4-tetrazole (PAT) and 5,5′-styphnylamino- 1,2,3,4-tetrazole (SAT) were designed and investigated theoretically. Density functional theory has been explored to investigate the geometric, electronic structures, band gaps, and heats of formation. The detonation performance was evaluated by using Kamlet-Jacobs equations based on the calculated densities and enthalpy of formation (EOF). The thermal stability of these compounds was studied by calculating bond dissociation energies and energy gaps. Proper numbers of 5-aminotetrazole (5-AT) moieties can enhance the EOFs of explosives, further improving the detonation performance as well as nitro group. Though introducing more nitro-groups into TATB frameworks, NH-moieties can retain the intramolecular hydrogen-bond, which can enhance the crystal-packing and physico-chemical stability. Meanwhile, noncovalent interaction (NCI) plots reflects that intermolecular interaction also has a crucial influence on the mechanical sensitivity for the designed derivatives, except for the energy gap (ΔE) and bond dissociation energy (BDE). UV/Vis spectra and 15N isotropic magnetic shielding were further computed for characterizing and predicting the molecular structure and reaction mechanism towards the future experiments. The predicted performance implies that the designed molecules are expected to be promising candidates for multi-nitrogen energetic materials.

Synthesis and Properties for Benzotriazole Nitrogen Oxides (BTzO) and Tris[1,2,4]triazolo[1,3,5]triazine Derivatives

Herein we first report a novel method of synthesis fused ring nitrogen-enriched compounds by intramolecular cyclization reaction. Some of them were characterized by IR, 1 H and 13 C NMR spectroscopy. Most of them exhibit outstanding positive heat of formation (155-376 kJ/mol). Densities of these compounds fall in the range between 1.7321-1.8847 g.cm -1 , which places them in a class of relatively dense energetic materials. Their physical properties were evaluated by Gaussian 09, and EXPLO5 6.02 calculations. Their detonation velocities and pressures were calculated to fall in the range of 6713-8441 m.s-1 and 14.47-30.61 Gpa.

Refractive index matching cooling fluids for diode pump solid state lasers

Diode pump solid state lasers (DPSSLs) have been widely used in various fields such as material processing, the military, and medical and scientific research because of their high efficiency, long life, good beam quality, and compact structure. In this paper, a variety of refractive index matching cooling fluids was used in DPSSLs. Liquids examined include nontoxic and minimally toxic mineral oil (M98511), (KN-X (4006, 4010, 4016)), dialkyl ester compounds (B109815 and D109648), and chlorinated paraffin (041102-52). Their properties, including refractive index, temperature coefficient of the refractive index (DN/dt), dynamic viscosity, absorption coefficient, and thermal conductivity, were studied. The DN/dt of the matching liquid coolant was −3.6u2009×u200910−4 to −3.9u2009×u200910−4, and complete absorption at 808u2009±u20095u2009nm was better than 0.001%. Additionally, the best absorption coefficient at 1064u2009±u20095u2009nm reached 0.144%, which was much better than the Cargille samples 2.256%.