Studies On Synthesis, Characterization And Properities Of The Novel Azide And Diazo Energetic Compounds

At present, lead azide (LA) is only military primary explosive in the world, but thedisadvantages are very sensitive to mechanical stimulation, low sensitivity to flame andacupuncture, very dangerous to achieve detonation in the absence of constraints, and heavymetal lead content up to71.14%. The types of industrial primary explosives are also less,which have dinitrodiazophenol (DDNP), zinc tri(carbohydrazide) perchlorate (GTX) andnickel hydrazine nitric (NHN), and so on. In searching for finding an alternative and betterperformance primary explosive, this paper was combined environmental–friendly primaryexplosives of the new concept standards, and followed with the development direction ofhigh–energy–insensitive energetic coordination compounds. Moreover, this papersystematically studied the synthesis, crystal structures, thermal decomposition,non–isothermal kinetics, heat of combustion, sensitivity properties and applied research of40species of azide and diazo energetic compounds. It can provide basic data for newprimary explosives. The main contents and conclusions are summarized as follows:(1) Design philosophyThe main challenge is high nitrogen–content on designing of energetic compound, andhigh energy and low sensitivity that it should be safe enough to prepare and handle.Designing the molecular structure of azide energetic compounds is [M(L1)x(N3)2]n, and itcan form single–core, multi–core,1D linear or2D plane structures. And designing themolecular structure of the diazo energetic compounds is [M(L2)x](ClO4)2, and it can form3D MOFs structures with choosing a bidentate ligand, which will be one of thedevelopment of energetic compounds.M are metal cations such as Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II),which have a very significant catalysis for combustion and explosion.Due to high nitrogen–content and high energy low sensitivity of energetic ligands L isalso contradictory, ligands L should consider the energetic structures and nitrogen contents,and are to identify10kinds of the high–nitrogen straight–chain ligands (N%=37.00~47.00%) and azole–ring ligands (N%=40.00~84.00%). In addition, we can draw the highest occupied molecular orbital (HOMO) and the lowest figure unoccupiedmolecular orbital (LUMO) figure of the energetic ligands by Gaussian03software, whichwere predicted a possible coordination nitrogen atoms of the energetic ligands. Theoreticalpredictions and experimental results of crystal structures are consistent.(2) Synthesis and crystal structures characterization of energetic compoundsThis paper was prepared the39kinds of energetic azide compounds and five kinds ofdiazo energetic compounds, of which42new kinds of energetic compounds wereunreported previously. Eight kinds of energetic azide compounds and one kind of diazoenergetic compound were obtained with the slow evaporation of solvent for the first time.The maximum nitrogen–content of energetic compound is manganese1,5–aminotetrazoleazide (74.34%), which is to determine the molecular structurethe and highestnitrogen–content energetic compound in the world.The molecular structures of energetic compounds illuminate the coordination modes ofazido ligand, energetic ligands and the central metal ion, and prove single–core, multi–core,1D chain,2D planar and3D MOFs structures. The obtained results provide the theoreticalfoundations for further studing on the relationships between their structure characteristicsand configuration properties.(3) The thermal decomposition, heat of combustion and sensitivity performanceThe thermal decomposition, heat of combustion, impact sensitivity, friction sensitivityand flame sensitivity of azide and diazo energetic compounds were investigated. The resultsshow that the main exothermic peak temperatures of11kinds of copper compounds in the45kinds of energetic compounds are180.8~275.4oC, which basically meet the200oC ofenvironment–friendly new concept in primary explosives standard. At the same time, theheat of combustion is reduced and sensitivity is more sensitive with the increase of nitrogencontent of energetic compounds. We can infer that thermal decomposition, heat ofcombustion and sensitivity performance of azide and diazo energetic compounds with metalions, the number and coordination modes of energetic ligands, coordination modes of azidoions, oxygen balance, nitrogen content and other factors are associated.(4) The leading indicator for energetic compounds used as potential primaryexplosives: minimum initiating charge determination The minimum initiating charge was tested for azide and diazo energetic compoundsaccording GJB method. The results showed that copper1,1’–diazo–1,3,4–triazole perchloric(50mg) can successfully detonate PETN in the diazo energetic compounds, which haspotential applications in industrial detonator. The copper hydrazine azide (30mg) cansuccessfully detonate RDX in azide straight–chain energetic compounds. The copper1,5–aminotetrazole azide (30mg) and lead1,5–aminotetrazole azide (10mg) cansuccessfully detonate RDX. They have potential applications in military detonators.(5) Landmark research results: potential military primary explosives andindustrial primary explosivea) Copper1,5–Aminotetrazole AzideCompared with LA primary explosive, the advantages are that detonation velocity is6200m s1when the charge density is1.78g cm3, plasma sensitivity is1.508mJ, and theminimum initiating charge for successfully detonating RDX is30mg. Therefor, it is anenvironmentally friendly potential military primary explosive.b) Lead1,5–Aminotetrazole AzideCompared with LA primary explosive, the advantages are that detonation velocity is4686m s1when the charge density is3.33g cm3, plasma sensitivity is1.975mJ, theminimum initiating charge for successfully detonating RDX is10mg, it can reduce thepollution by increasing the nitrogen content and reducing the lead content. It is a promisingmilitary primary explosive and get a preliminary application.c) Copper1,1’–Diazo–1,3,4–triazole PerchloricCompared with GTX industrial primary explosive, the advantages are no endothermicpeak of thermal analysis, exothermic peak of275.4oC, high heat of combustion (it is1.6times than that of GTX and equal with that of RDX and HMX) and high nitrogen content.Compared with NHA industrial primary explosive, the advantages are regular crystal, goodfluidity, heat resistance reaches above200oC and low minimum initiating charge.Therefore, it is an environmentally friendly potential industrial primary explosive.