Base-promoted decarboxylative gem-diazo-C-coupling: Synthesis , characterization and performance of nitrotriazolylformazans

Formazans, containing the characteristic chain of atoms -NN-CRN-NH- (R = -CN or tetrazyl) are nitrogen-rich and conjugated compounds exhibiting unique properties. In this work, new cyano and tetrazylformazans and their series of nitrogen-rich energetic salts were synthesized via base-promoted gem-diazo coupling reaction. The resulting derivatives were well characterized, and their performances were further investigated. The experimental results indicated that the decomposition temperatures of 1-12 lie between 159 degrees C and 279 degrees C. All of them are much less impact sensitive (>= 20 J) than trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and 1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). They have relatively high positive heats of formation between 987.7 and 1457.3 kJ mol(-1), which are much higher than those of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20), RDX and HMX. The calculated detonation pressures (p) range between 23.2 and 30.2 GPa and calculated detonation velocities (D) between 7480 and 8274 m s(-1). Interestingly, compound 4 shows excellent laser ignition combustion performance.

Automated summary

In this study, new nitrogen-rich energetic salts were synthesized and characterized. The results showed that these compounds have high heats of formation, low impact sensitivity, and good combustion performance.