Study On The Synthesis And Reaction Mechanisms Of Arylpentazole Compounds

In recent years,multi-nitrogen have become research foucus in the field of energetic materials due to their advantages of high density,high energy,low enthalpy of formation,and pollution-free;at the same time,some of the multi-nitrogen compounds show good antibacterial effects,which makes it have broad application prospects in biomedicine.Among them,N₅^-ion has become a research hotspot of multi-nitrogen because of its high chemical reactivity,and stable structure.At present,the only way to obtain N₅^-ion is to cleave the C-N bond of the arylpentazole.However,the poor stability of arylpentazole compounds leads to the problems of many by-products,low product yield in the preparation process of N₅^-ion.Therefore,it is necessary to explore the synthesis,the thermal decomposition and related mechanisms of arylpentazole compounds.Firstly,the thermal stability of arylpentazole with different substituents was analyzed by the mass spectrometry and quantum chemistry calculations.The results show that when the substituents are located in the para and meta positions,the stronger the electricity supply of the substituents,the stronger the stability of the arylpentazole.When the substituent is located in the ortho position of the pentazole group,the steric hindrance effect of the group will greatly reduce the stability of the arylpentazole,even if the substituent has a strong electricity supply.Later,this thesis tested the characteristic curve of the ultraviolet-visible light absorption spectrum of 3,5-dimethyl-4-hydroxyphenylpentaazole（HMPP）with temperature changes,and explored its thermal decomposition process.From the test results,it can be determined that the characteristic ultraviolet-visible absorption of 3,5-dimethyl-4-hydroxyphenylpentaazole（HMPP）occurs at 284 nm,and the ultraviolet-visible absorption of 3,5-dimethyl-4-hydroxyphenyl azide（HMPA）occurs at 258 nm.Single crystal diffraction confirmed that the thermal decomposition products of HMPP.And on this basis,the thermal decomposition mechanism of HMPP was guessed.The theory of charge transfer complexes is used to try to enhance the thermal stability of HMPP.The experimental results found that:p-benzoquinone and 2,6-dichloro-1,4-benzoquinone can be used as electron acceptors to synthesize charge transfer complex with HMPP.And the decomposition temperature of the complex CT₁synthesized by p-benzoquinone and HMPP is slightly higher than that of HMPP itself.The experimental results of trying to synthesize supramolecular compounds found:α-/β-/γ-cyclodextrin all cannot obtain supramolecular inclusion compound with HMPP.However,by comparing the results of the UV-vis light absorption test,it is found that the cyclodextrin molecule still has a mitigation effect on the thermal decomposition of HMPP.It is guessed that there is a certain force between the the surface atoms of the cyclodextrin and HMPP,which may slightly increases the stability of HMPP.