Synthesis And Hydrogenolysis Of Non-benzyl Substituted Hexaazaisowurtzitane

Hexanitrohexaazaisowurtzitane(HNIW,CL-20)is one of the best explosives in the world today,and it has been widely used in solid propellants,composite explosives,gun powders,etc.In traditional preparation of CL-20,two-step hydrogenysis from HBIW is required to obtain the best precursor TAIW.However,expensive palladium catalyst is used in both two-step hydrogenolysis,making the cost of producing CL-20 very high.Therefore to explore a new way to synthesize non-benzyl substituted hexaazaisowurtzitane and cheaper route to prepare CL-20 is of great significance.In this paper,using 1-aminomethylnaphtalene,2-aminomethylnaphtalene and 2-furylmethylamine as condensation reactants,several non-benzyl substituted hexaazaisowurtzitanes were synthesized,and their hydrogenolysis process was carried out respectively.The synthesis process was studied as follows:First of all,a new method of preparing TAIW can be achieved by only one-step hydrogenolysis of the condensation product,and the by-product of hydrogenolysis can be recycled in the synthesis schedule.(1)The condensation reactants 1-aminomethylnaphtalene and 2-aminomethylnaphtalene were synthesized by delepine reaction with 1-bromomethylnaphthalene and 2-bromomethylnaphthalene respectivily.(2)Two novel non-benzyl cage precursors hexa(1-naphtylmethylene)hexaazaisowurtzitane(H(1-Np)IW)and hexa(2-naphtylmethylene)hexaazaisowurtzitane(H(2-Np)IW)were obtained by condensation of 1-aminomethylnaphtalene and 2-aminomethylnaphtalene with glyoxal respectively,the yield was 45.3% and 56.7% correspondingly.(3)TAIW was obtained by only one-step hydrogenolysis of H(1-Np)IW and H(2-Np)IW,the yields were 54.2% and 57.0% respectively,which avoided the use of the palladium catalyst in the secondary hydrogenolysis of traditional CL-20 preparation process,and reduced the cost of CL-20.(4)Meanwhile,the by-product methylnaphthalene can be recycled as raw material for the synthesis of aminomethylnaphtalene after separation and further bromination,which not only reduced the cost of preparing CL-20,but also reduced the environmental pollution caused by the by-product.Secondly,a novel non-benzyl substituted hexaazaisowurtzitane—tetraacetyldi-(2-naphtylmethylene)hexaazaisowurtzitane,was obtained by shortening the hydrogenolysis time of H(2-Np)IW.Its structure was characterized,and the yield was 56.5%.The experimental result shows that different hydrogenolysis products can be obtained by controlling the time of hydrogenolysis,and the two naphthalene methylene groups can be removed by only prolonging the time of hydrogenolysis to obtain TAIW rather than secondary hydrogenolysis by changing the reaction system.Finally,hexafurfurylhexaazaisowurtzitane(HFIW)was successfully synthesized by condensation of 2-furylmethylamine with glyoxal,and the yield was 13.5%.We attempted to hydrogenolysize HFIW,and the hydrogenolysis products were preliminarily determined.The hydrogenolysis of HFIW was attempted to studied.It was found that the stability of HFIW was poor and the cage structure of HFIW can be easily broken during the hydrogenolysis process.The hydrogenolysis products were preliminarily determined and the hydrogenolysis process of HFIW was predicted.