Sodium 5‐nitrotetrazolate dihydrate (NaNT) is a useful precursor compound for the synthesis of lead‐free primary explosives; however, currently employed syntheses for the compound are tedious, dangerous, and plagued by impurities. Through comprehensive analysis, we elucidate the identity of the most detrimental impurities and further report an improved procedure for preparation of NaNT, which greatly improves the purity, while avoiding the handling of acid copper(II) nitrotetrazolate, a highly sensitive explosive intermediate. In the new procedure, 5‐aminotetrazole is diazotized with sodium nitrite, cupric sulfate, and nitric acid. Copper is precipitated as its oxide and the aqueous solution evaporated. After soxhlet extraction with acetone, large crystals of NaNT are obtained. The prepared material is suitable for preparation of lead azide replacement DBX‐1 [copper(I) 5‐nitrotetrazolate] as evidenced by successful use in M55 stab detonators.

In the present work resonance acoustic mixing was applied to afford a practical and environmentally friendly approach to produce and scale up cocrystals. Scale-up options for producing cocrystals are limited. Solution-phase cocrystallizations, although amenable to scale-up in stirred tanks, may be limited due to multiple solubility constraints on both coformers and the product cocrystals, resulting in challenges to find feasible processing conditions. While mechanochemical methods such as liquid-assisted grinding (LAG), solid drop grinding (SDG), and ball-milling have been shown to be more general than solution-phase methods, they are also more difficult and impractical to scale up. In the present work a resonant acoustic mixer was used to intimately mix active pharmaceutical ingredient (API) compound and coformer at high frequency, in the presence of a small amount of solvent, to induce conversion to cocrystals with no grinding media required. Carbamazepine (CBZ) and nicotinamide (NCT) were used as a model system for successfully producing CBZ:NCT cocrystals. Thus, it was shown that resonant acoustic mixing provides the mixing intensity required of lab-scale mechanochemical methods, such as liquid -assisted grinding, but now on a platform more amenable to larger-scale manufacture. Resonant acoustic mixing in general has been demonstrated to be scalable to volumes greater than 200 L and thus affords a potential new platform for cocrystallization processes.

A novel cocrystal (NEX‐1) of CL‐20 and MDNT is presented herein. The CL‐20: MDNT cocrystal, obtained in high yield by resonant acoustic mixing, shows new properties versus the discrete components. This is the first example of cocrystallization of CL‐20 where the new material is less sensitive to friction than CL‐20 itself, while demonstrating similar impact and ESD sensitivity. The CL‐20: MDNT cocrystal shows promise in the production of new energetic materials of interest by the cocrystallization of well‐characterized components.

Resonant acoustic mixing (RAM) was applied to the preparation of an energetic‐energetic cocrystal comprised of CL‐20 and HMX in a 2 : 1 mol ratio. We have prepared the cocrystal using the RAM technology in a resource‐efficient manner providing near quantitative yield. The cocrystalline product from the RAM preparation is consistent with the product from solution crystallization.

Copper(I) 5-nitrotetrazolate (DBX-1) has emerged in recent years as a primary explosive that could serve as a replacement for lead azide (LA), a widely used explosive that has fallen out of favor due to its toxicity and chemical compatibility issues. While there is a significant amount of interest in this material, the development of DBX-1 has been hampered by the tedious and poorly understood chemical process for its preparation. To consistently produce DBX-1, two explosive intermediates must be isolated, and one of them requires purification. In this article, we present an improved process for the synthesis of DBX-1. In this process, neither of these intermediates needs to be handled by an operator, and the purification step is no longer necessary. It would be practical to perform the entire process under remote control, a necessity for energetic material manufacturing. We discuss the implications of our findings for the development of a robust process for the reproducible production of high quality DBX-1.