In order to explore new high-nitrogen energetic materials,2,3,5,6-tetra(1H-tetrazol-5-yl)pyrazine(H4TTP)was synthesized by oxidative condensation and azide-cyano cyclization reaction in a two-step process using 2,3-diamino-2-butene-dicarbonitrile(DAMN)as raw material.H4TTP was characterized by Fourier transform infrared spectroscopy(FTIR),nuclear magnetic resonance(NMR),mass spectrometry and elemental analysis.Based on the original process,the process was im-proved by adding tetrabutylammonium bromide(TBAB)as stabilizer and changing the final acidity value.On the basis of the single factor test,the reaction conditions were optimized by the response surface method with the yield of H4TTP as the re-sponse value.The effects of reaction temperature,reaction time,and molar ratio of pyrazine tetracosanoic acid(TCP)and sodium azide(NaN3)on the cyclization reaction were studied.A regression equation was established between the yield of H4TTP and the three correlates.The R2 value of the resulting model is 0.9992,indicating that the regression equation is highly fitted.The optimized conditions for the cyclization reaction are as follows:dimethyl sulfoxide(DMSO)as solvent,TBAB as stabilizer,the molar ratio of TCP and NaN3 is 1∶4.4,the reaction temperature is 124 ℃,the reaction time is 42h,the stir-ring rate is 400 r/min,and the yield of H4TTP is 89.73％.The experimental yield is basically consistent with the model predic-tion value of 90.61％,and the reasonableness of the selected model is further verified.Compared with the original process,the yield of cyclization reaction of the improved process is increased by about 7％.
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