Study On The Performance Of New Energetic Oxidant N,2,2,2-Tetranitroacetimidic Acid

Oxidant is an important part of the solid propellant,N,2,2,2-tetranitroacetimidic acid(TNAA,C2HN5O9)is a new potential energetic halogen-free oxidizing agent with 30.0%of oxygen balance.In this paper,we studied TNAA synthesis,solubility,sensitivity,moisture absorption,thermal decomposition behavior,chemical compatibility.and detonation performance,etc.It provides a strong technical and theoretical support for the application of new energetic oxidant-TNAA.1,1-diamino-2,2-dinitroethylene was prepared from 2-methyl-4,6-dihydroxypyridine,and then TNAA was got by the FOX-7 nitrification.The structure data of TNAA was obtained by NMR,FTIR and X-ray diffraction.And it's crystal spatial structure belongs to monoclinic system and P21/c space group,the crystal density is 1.844g/cm-3.TNAA incompatibled with most solvent-containing reactive groups,such as methanol,acetone,water,DMF,ethyl acetate,ether,etc.And TNAA solubility tests showed TNAA had good performance in dichloromethane and chloroform of 11.54g/100g and 2.7g/100g respectively,but insolubled in non-polar solvents such as tetrachloromethane and n-hexane.TNAA with weight loss of 4.59%at 75? after 48 hours,and when TNAA at a temperature of 30.0? and the air humidity of more than 70%,there will be significant moisture absorption of 1.36%weight reduction after 24 hours.This showed that cool and dry environment would be better for TNAA storage.By mechanical sensitivity tests,TNAA impact sensitivity(28%,2kg,250mm)amount to AP and friction sensitivity(72%,1.5kg,90°swing angle)amount to RDX.The thermal behavior of TNAA was studied under the non-isothermal conditions with differential scanning calorimeter(DSC)method.TNAA has a melting point of 91.6? and a decomposition peak temperature of 147.8?.In order to obtain the kinetic parameters of the obvious exothermic decomposition reaction for TNAA,a multiple heating method(Kissinger's method and Ozawa's method)was employed.The values of the apparent activation energy Ek is 130.24 kJ·mol-1 obtained by Kissinger's method,and E0 is 130.51 kJ mol-1 by Ozawa's method,respectively.The values of pre-exponential constant(logA)is 16.11 s-1 and the critical temperature of thermal explosion(Tb)of the compound is 137.86 ?,the initial decomposition temperature(Tp0)is calculated to be 127.10?,respectively.The formation heat and detonation parameters of TNAA were calculated by density functional theory(DFT)and Kamlet formula.The formation heat of TNAA is-123.63kJ·mol-1,the detonation heat is 4391.33kJ·kg-1,the detonation velocity is 8.15 km·s-1 the detonation pressure is 29.88GPa,the burst temperature is 4382.72K,the explosion capacity is 679.33 L·kg-1.The results showed that TNAA is a kind of energetic material with detonation energy higher than TATB but lower than HMX.And the compatibility of TNAA with common solid propellant components were studied by differential scanning calorimeter(DSC)method.The results show that TNAA/HMX,TNAA/RDX,TNAA/CL-20 and TNAA/Al possess good compatibility of A,TNAA and AP have moderate compatibility of between B and C,and the compatibility of TNAA with TNT,AN,FOX-7,NC is C,while TNAA/HTPB,TNAA/1#Centralite,TNAA/Mg,TNAA/PbC03 and TNAA/Boron would have badly chemical reaction,so the compatibility all are D.