Backbone Isomerization to Enhance Thermal Stability and Decrease Mechanical Sensitivities of 10 Nitro-Substituted Bipyrazoles

• Published in: ACS applied materials & interfaces Vol. 15; no. 41; pp. 48346 - 48353
• Main Authors: Meng, Jingwei, Fei, Teng, Cai, Jinxiong, Lai, Qi, Zhang, Jinya, Pang, Siping, He, Chunlin
• Format: Journal Article
• Language: English
• Published: American Chemical Society 18.10.2023
• Subjects: Energy, Environmental, and Catalysis Applications; trinitromethyl; bipyrazole; high-energy density oxidizer; thermostability; backbone isomerization
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.3c12574

The development of novel, environmentally friendly, and high-energy oxidizers remains interesting and challenging for replacing halogen-containing ammonium perchloride (AP). The trinitromethyl moiety is one of the most promising substituents for designing high-energy density oxidizers. In this study, a backbone isomerization strategy was utilized to manipulate the properties of 10 nitro group-substituted bipyrazoles containing the largest number of nitro groups among the bis-azole backbones so far. Another advanced high-energy density oxidizer, 3,3′,5,5′-tetranitro-1,1′-bis­(trinitromethyl)-1H,1′H-4,4′-bipyrazole (3), was designed and synthesized. Compared to the isomer 4,4′,5,5′-tetranitro-2,2′-bis­(trinitromethyl)-2H,2′H-3,3′-bipyrazole (4) (T d = 125 °C), 3 possesses better thermostability (T d = 156 °C), which is close to that of ammonium dinitramide (ADN) (T d = 159 °C), and it possesses better mechanical sensitivity (impact sensitivity (IS) = 13 J and friction sensitivity (FS) = 240 N) than that of 4 (IS = 9 J and FS = 215 N), thereby demonstrating a promising perspective for practical applications.