Studies on Synthetic Technology and Reduced Sensitivity Technology of Hydrazinium Nitroformate

A practical synthetic route of hydrazinium nitroformate (HNF) was reported in this paper. The preparation of intermediate nitroform (NF) from isopropyl alcohol was investigated by utilizing anhydrous nitric acid (HNO3) as a nitrating system. The influence of various factors such as reaction temperature, time, and amount of anhydrous HNO3 on yield of NF, as well as the effect of temperature on the extraction efficiency was demonstrated. NF was obtained with an optimal yield of 53.6%, far beyond that reported in the literature (25%). The synthesis of HNF was followed by the neutralization reaction of NF with equal molar hydrazine hydrate (80%) instead of hydrazine anhydrous. With the purpose of decreasing the sensitivity, the crystal morphology of HNF was adjusted through varied crystallization methods such as antisolvent crystallization, sono-crystallization and sequential cooling crystallization. HNF crystals obtained from sequential cooling crystallization displayed excellent morphology with a length/diameter ratio (L/D) approximate to 1:1. Corresponding sensitivity performance toward external impulse, especially friction and electrostatic discharge, was improved greatly in comparison with that of crude HNF without the crystallization process. The synthetic route in this paper would provide a basis to promote the industrial production of NF and HNF.