Study On The Technique To Reduce The Sensitivity Of Hydrazinium Nitroformate And The New Method Of ProducingNitroform

Hydrazinium nitroformate (HNF) is a new type of compound with high energy and high oxygen content, which is mainly used to increase the energy properties as an oxidizer in the solid propellant. The sensitivity of HNF is affected by its purity and the characteristics of its crystal morphology. Therefore, it is important to control the process for producting high quality HNF and study the recrystallization process of HNF for reducing sensitivity.Nitroform was prepared by reacting isopropanol with nitric acid. The purity of nitroform could be reached99%by a new method of isolating. The new process for the isolation involved recrystallization, acidification, and extraction. In the process of preparing the HNF, various reaction conditions such as the water content of hydrazine, solvent dosage and reaction time on the HNF purity and yield were discussed. The result showed that the purity and yield of HNF reached99.7%and95.2%respectively under the optimum reaction conditions. The related structures were characterized and confirmed. In addition, the single crystal of HNF was obtained by controlling the evaporation of solvent.At22～55℃, the solubility of HNF in different solvents such as tetrahydrofuran, methanol, ethanol and acetonitrile were measured, respectively. The crystal was obtained by the solvent evaporation method, and the aspect ratio (L/D) was found to be relatively lower in methanol and acetonitrile solvents. Focus on the programmed cooling crystallization method, the impact factors on particle shape and size in the process of this crystallization method, such as solvent, the initial concentration, agitating, cooling rate and incubation time, were investigated. The optimal crystallization condition for producing cubic HNF particles was: acetonitrile as the solvent, the initial solution concentration of47%, the stirring speed of150r/min, the cooling rate of0.3℃/min, and raising the crystal time of100min. Five kinds of particle size categories of HNF particles such as40～60mesh,60～80mesh,80～100mesh,100～140mesh and140～200mesh size categories could be obtained simply by changing these different factors with different degree.The results were characterized by SEM and sensitivity (the impact sensitivity and friction sensitivity) test. The sensitivity test results showed that sensitivity of cubic, particles uniform and defectless HNF crystal decreased with different extent compared with the virgin HNF crystal. Impact sensitivity and friction sensitivity of HNF decreased along with decrease of particle size. The impact and friction sensitivity of HNF with70-80μm size reduced by30%and27%. Exploring new method for producing nitroform was very meaningful. New invention would be desicribed in terms of using some methyl ketone compounds and ethanol as the starting material. The optimal reaction condition was found through investigating reaction time, reaction temperature, and nitrating agent and its dosage. The result indicated that the optimal method for producing nitroform was reacting acetyl acetone with nitric acid and nitroform yield reached36.76%.