The Development of a New Synthesis Process for 3,3′‐Diamino‐4,4′‐azoxyfurazan (DAAF)

Abstract

Process optimization studies were performed for the preparation of the high explosive 3,3′‐diamino‐4,4′‐azoxyfurazan (DAAF). These process studies were pursued to address issues such as problematic waste generation products, particle size, impurities, and manufacturability. This paper describes the original synthesis method and inherent issues. An optimization process was designed to investigate the issues with purity and manufacturability. Particle size effects were addressed by adding a recrystallization step to the synthesis. Ultimately, a complete solution to all observed issues was found with a new synthesis process, which now allows DAAF to be prepared without any impurities, with good particle size and without the need for recrystallization. Importantly, the new synthesis process can be performed in an environmentally friendly manner, with the production of non‐hazardous waste.

Crystal Structures of Furazanes

“…The calculated density at 173 K is 1.842 g·cm −3 , which is similar to the previously reported density of 1.84 g·cm −3 (X-ray analysis at 153 K) [11]. Compound 3 is planar, only the nitro moiety is slightly tilted against the furazan plane by a torsion angle of O2-N3-C1-C2 = 4.4°.…”

1H, 13C and 15N Nuclear Magnetic Resonance Analysis of 3,3’,4,4’-Diaminoazoxyfurazan Obtained by Oxidation of 3,4-Diaminofurazan with Peroxyformic Acid

“…al. showed that for DAAF synthesized with Oxone, an endothermic peak assigned to the melting process was observed [4]. On the DTA curve of a sample of raw DAAF synthesized by our method, this endothermic peak was not observed.…”

“…In the Zelenin method [2] the byproduct is 3,3'-dinitro-4,4'-azoxyfurazan, which is sensitive to friction and impact. The last method, described by the Francois group [4], enables DAAF to be obtained in high yield (84%). The authors of this study [4] reported that they also obtained DAAF by using m-chloroperoxybenzoic acid (MCPBA), but did not provide details.…”

“…The structure of the DAAF molecule was confirmed by using 1 H and 13 C NMR spectroscopy [2,4] All chemicals were of analytical grade and were obtained from commercial sources (Avantor, Sigma-Aldrich). DAF was synthesized at the Military University of Technology by the Coburn method [5].…”

“…( [4]. The DAAF obtained by the Solodyk method [1] contains 3-6% impurities, such as its precursor DAF, 3-amino-4-nitrofurazan and 3-amino-4-nitrosofurazan [1].…”