The Preparation And Performance Study Of Positive Oxygen-balance Energetic Materials Based On Pyrazole And Its Derivatives

In the past few decades,the field of energetic materials has been looking for new energetic oxidizers（HEDOs）that can replace ammonium perchlorate（AP）.Among the compounds that have been explored,energetic derivatives based on nitrogen-containing five-membered heterocycles have received extensive attention from the scientific community.This work focuses on the study of synthesis and performance of polynitro energetic compounds and their derivatives based on pyrazole.The specific content and results are as follows:（1）The design and preparation of 3,5-dinitro-4-nitroamino-1-（trinitromethyl）pyrazoleFrom 4-chloropyrazole,compound 3,5-dinitro-4-nitroamino-1-（trinitromethyl）pyrazole,OB(Ω_CO2=15.26%),was obtained for the first time with 5 steps reaction.The main product and intermediates were fully characterized by IR spectroscopy,elemental analysis,NMR spectroscopy.（2）Synthesis the derivatives of 3,5-dinitro-4-nitroamine-1-（trinitromethyl）pyrazoleCombining 3,5-dinitro-4-nitramino-1-（trinitromethyl）pyrazole reacts with potassium iodide dipotassium 3,5-dinitro-4-nitroamine-1-（dinitromethyl）pyrazole was obtained,which was acidify by H₂SO₄,monopotassium 3,5-dinitro-4-nitroamine-1-（dinitromethyl）pyrazole was precipitated at low temperature,and 4-diazo-3-nitro-5-oxo-1-（dinitromethyl）pyrazole obtained under high temperature conditions.The chloroform solution of 3,5-dinitro-4-nitroamino-1-（trinitromethyl）pyrazole is heated to reflux,then obtaining the compound 3,5-dinitro-4-amino-1-（trinitromethyl）pyrazole.The structures of the above compounds were characterized by NMR,FTIR,LC-MS,element analysis,and single crystal X-ray diffraction.（3）Performance study of 3,5-dinitro-4-nitroamino-1-（trinitromethyl）pyrazole and its energetic derivativesThe decomposition temperature of related compounds was tested by DSC,Among which dipotassium 3,5-dinitro-4-nitramino-1-（dinitromethyl）pyrazole has good thermal stability(T_dec=282℃).With the DSC-TG-FTIR method,we studied the thermal decomposition mechanism of monopotassium 3,5-dinitro-4-nitramino-1-（dinitromethyl）pyrazole.Sensitivity of energetic compounds were tested using the BAM technology.Through density functional theory（DFT）,Multiwfn program,isodesmic reaction,Kamlet-Jacobs equation,the density,heats of formation and detonation performance of related compounds were calculated.Among all the synthesized compounds,dipotassium 3,5-dinitro-4-nitramino-1-（dinitromethyl）pyrazole(T_dec=282℃,IS=0.25 J,FS=40-48 N,D=7.572 km·s^-1,P=27.54 GPa,Ω_CO2=4.01%,ρ=2.068 g·cm^-3)and 4-diazo-3-nitro-5-oxo-1-（dinitromethyl）pyrazole(T_dec=138℃,IS=1<1 J,FS=40 N,D=9.135 km·s^-1,P=37.50 GPa,Ω_CO2=-9.27%,ρ=1.837g·cm^-3),which were expected to become a novol green lead-free primary explosive;Compound 3,5-dinitro-4-amino-1-（trinitromethyl）pyrazole(T_dec=133℃,IS=<1 J,FS=30 N,D=9.016 km·s^-1,P=37.4 GPa,Ω_CO2=4.97%,ρ=1.917 g·cm^-3)have excellent comprehensive properties which have application potential in the field of HEDOs.