Different Stoichiometric Ratios Realized in Energetic–Energetic Cocrystals Based on CL-20 and 4,5-MDNI: A Smart Strategy to Tune Performance

Abstract

A new 1:3 CL-20 (2,4,6,8,10,12-hexanitrohexaazaisowurtzitane)/4,5-MDNI (1-methyl-4,5-dinitroimidazole) cocrystal (1) in combination with the previously reported 1:1 CL-20/4,5-MDNI cocrystal (2) together have been first realized in different stoichiometric ratios based on CL-20 and 4,5-MDNI in energetic−energetic cocrystals. Subtle differences in intermolecular interactions and packing motifs may lead to the formations of the cocrystals 1 and 2 by structure comparisons. Moreover, properties (e.g., density, thermal properties, sensitivity, and detonation performances) varied significantly under different stoichiometric ratios and crystal structures. For instance, the comprehensive performances of cocrystal 1 (ρ: 1.813 g/cm 3 ; D: 8604 m/s, P: 34.45 GPa; IS: 16 J) were less excellent than those of cocrystal 2, whereas cocrystal 1 exhibited a detonation velocity superior to that of LLM-105 (2,6-diamino-3,5-dinitropyrazine-l-oxide, a relatively new insensitive explosive) and a low impact sensitivity close to that of LLM-105; thus, cocrystal 1 may act as a new high-energy insensitive explosive. Moreover, the findings of CL-20/4,5-MDNI cocrystals may offer new insights into the design and preparation of energetic cocrystals with different ratios and other energetic cocrystals, enrich better understanding of the formations for energetic cocrystals, and provide a smart strategy to tune performances.

Optimized energetic HNTO/AN co-crystal and its thermal decomposition kinetics in the presence of energetic coordination nanomaterials based on functionalized graphene oxide and cobalt

“…[17][18][19] Several energetic co-crystals with interesting features have been developed so far and the topic continues to attract current/future and increasingly intense international discussion to fulll the requirement of the next generation of EMs. [20][21][22] As one of the most interesting propellant oxidizer and explosive ingredient, AN displays prominent characteristics such a positive oxygen balance, low cost, availability, and 100% of gaseous decomposition products. 23 Nonetheless, AN exhibits unneglectable shortcomings such as low energy rate, poor ignitability, lower burning rate, high hygroscopicity, and an ambient temperature polymorphic solid-solid phase transition, acknowledged as one of the foremost reason for damaging and caking of AN-based energetic formulations, which inhibits its extensive employments, particularly as solid-propellant ingredient.…”

Nitramine-Based Energetic Cocrystals with Improved Stability and Controlled Reactivity

“…In fact, the above-mentioned intermolecular interactions are usually present together, and they may reach an equilibrium to stabilize the crystal lattice. For instance, the formation of the CL-20/4,5-MDNI 1:1 cocrystal is primarily dependent on three major types of intermolecular forces, namely, CH···O, NO 2 –π, and CH···N, whereas CL-20/4,5-MDNI 1:3 cocrystal lacks a sufficient CH···N interaction . The formation of the CL-20/1,4-DNI cocrystal also depends on these three types of intermolecular forces (Figure c) .…”

“…In fact, the above-mentioned intermolecular interactions are usually present together, and they may reach an equilibrium to stabilize the crystal lattice. For instance, the formation of the CL- 40 The formation of the CL-20/ 1,4-DNI cocrystal also depends on these three types of intermolecular forces (Figure 1c). 21 For the HMX/ANPZO cocrystal, two types of hydrogen bonds (N−H•••O and C−H••• O, which have lengths of 0.2452 and 0.2403 nm, respectively) can be formed.…”

Microchannel-confined crystallization: shape-controlled continuous preparation of a high-quality CL-20/HMX cocrystal

“…In energetic cocrystals, 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaiso-wurtzitane CL-20-based cocrystals are particular of great interest as one of the effective strategies to achieve a balance between performance and safety by reducing the high sensitivity of CL-20. [1][2][3][4][5][6][7][8][9][10][11] Until recently, more than ten CL-20-based cocrystals have been reported offering attractive properties. [2][3][4][5][6][7][8][9][10][11] In particular, the CL-20/1,3,5,7tetranitro-1,3,5,7-tetrazacyclooctane (HMX) cocrystal has become one of the most promising energetic cocrystals due to its high explosive power and good mechanical sensitivity.…”

“…[1][2][3][4][5][6][7][8][9][10][11] Until recently, more than ten CL-20-based cocrystals have been reported offering attractive properties. [2][3][4][5][6][7][8][9][10][11] In particular, the CL-20/1,3,5,7tetranitro-1,3,5,7-tetrazacyclooctane (HMX) cocrystal has become one of the most promising energetic cocrystals due to its high explosive power and good mechanical sensitivity. 3 Various methods have been employed for fabricating a nanoscale CL-20/HMX cocrystal, such as ultrasonic sprayassisted electrostatic adsorption, 12 spray flash evaporation, 13 and bead-milling.…”