Synthesis Of Nitropyrazole Derivatives And Its Energetic Salts

Recently,much attention have been focused on the development of modern high energy density materials?HEDMs?in the flied of energetic materials.High energy and low sensitivity are always the central theme of weaponry,similarly,are common foundation problems that propellants and explosives are facing.However,high energy and low sensitivity is usually a contradiction.Therefore,rational design strategies for explosives molecular structure are necessary to solve this problem effectively.Nowadays,using energetic salts of heterocyclic with high nitrogen content as HEDMs has made great progress.Salt-based energetic materials often tend to exhibit lower vapor pressures and higher thermal stability than their atomically similar nonionic analogues.In addition,their properties are readily improved and optimized through judicious combination of different anions and cations,as well as a result of independent modification of cationic and anionic components.Pyrazole ring is considered to be the ideal structural unit to design nitrogen-rich heterocycle energetic materials.At the same time,the introduction of a nitro group can improve the oxygen balance and density of molecules,which is helpful to improve detonation performance.Studies show that azole compounds with two nitro groups have higher energy,are good structural units to build energetic compounds.In addition,fused-ring compounds compared with single-ring compounds have a more compact structure and higher density.They are beneficial to improve detonation performance.In this research,three parts of investigations have been designed and accomplished based on reviewing the history,current research status of part of elemental explosives,nitropyrazole derivatives and energetic salts:?1?We designed two new fused ring compounds containing nitropyrazole structural unit and developed synthetic routes.In this route,3,4-dinitro-5-hydrazinopyrazole is a key intermediate.?2?Firstly we synthesized 3,4,5-trinitropyrazole by literature methods,then we made it as a precursor for the study of 5-hydrazino substitution reaction,as a result,we can't obtain the 5-hydrazino substituted product by direct or indirect nucleophilic substitution.Secondly,during the study of 5-hydrazino substitution reaction,We superficially studied and compared different reaction conditions of part of intermediates,simultaneously,obtained the crystal data of compound 1-methoxymethyl-3,4,5-trinitro-pyrazole and analyzed its structure simply.?3?3,4-dinitro-5-amino pyrazole was synthesized,the target product were characterized by IR,NMR and MS.We used the improved method of Hofmann degradation reaction,that is to say we used KF/Al₂O₃ as the catalyst and the yield is over 87%.