Enzymatic nitration of triazoles by horseradish peroxidase for a safe synthesis of energetic materials

Nitration is an essential process for the synthesis of energetic materials. However, conventional nitration processes are prone to exothermic decomposition, which can lead to runaway reactions and catastrophic explosions. In addition, the use of strong acid causes corrosion of equipment and poses environmental contamination. This study examined enzymatic nitration as a safer and environmentally friendly method for synthesizing these materials. An enzymatic process using horseradish peroxidase (HRP) was adopted to nitrate a triazole, 3-amino-1,2,4-triazole. The reaction proceeded under mild aqueous conditions without the use of strong acids or extreme temperatures, highlighting the safety advantages of this enzymatic method. Ultraviolet-visible (UV-Vis) spectrophotometry, and quantitative nuclear magnetic resonance (qNMR) analyses confirmed the generation of 3-nitro-1,2,4-triazole from 3-amino-1,2,4-triazole. The temperature-dependent behavior was observed: the yield of 3-nitro-1,2,4-triazole was calculated to be 91.4%. These findings demonstrate that HRP-catalyzed nitration can serve as a practical and environmentally benign alternative to traditional acid-based nitration systems.