Lithium Nitropyrazolates as Potential Red Pyrotechnic Colorants

Abstract

Strontium-based red pyrotechnic colorants have fallen into disrepute due to the harmful influence of this alkaline earth metal on adolescents. In this context, the energetic character, safety, and combustion to benign nitrogen gas of nitropyrazoles are used for the design of the corresponding lithiated materials, which are investigated as potential replacements in the current work. For this purpose, the lithium salts of 3,4-dinitro-1H-pyrazole, 3,5-dinitro-1H-pyrazole, 4-amino-3,5-dinitro-1H-pyrazole, 3,4,5-trinitro-1H-pyrazole, and 4-hydroxy-3,5-dinitro-1H-pyrazole were extensively characterized by standard analytical methods, low-temperature single-crystal X-ray diffraction, studies of the thermo-chemical behavior, and sensitivity assessments. Our assumption that the high nitrogen contents and the low oxygen balances of these compounds would adjust a cool, reductive flame atmosphere essential for red emissions by lithium was put to the test.