Study On Synthesis And Properties Of TNINA

Compared with the traditional High Energy Density Materials(HEDMs),the nitrogenou s poly-heterocyclic energy compounds are a seires of representative HEDMs,their energy mai nly originates from C-N bond,N-N bond and ring tension.The nitro groups connecting wit h multiple nitrogen atoms in the ring structure not only increase theirs energy and density,bu t also improve their oxygen balance.The nitrogenous poly-heterocyclic energy compounds re ceive widely concern for the high energy,high density and good safety performance.This p aper described the synthesis of a new nitrogenous poly-heterocyclic energy compound:N-(1,4,6-trinitrohexahydroimidazo[4,5-d]imidazol-2(1H)-ylidene)nitramide(TNINA).The five-menbered ring 4,5-diamine-2-iminoimidazolidine was first synthesized by using 2,3,5,6-tetrahydroxypiperazine-1,4-dicarbaldehy and guanidine hydrochloride as sta rting materials.Then the reaction of 4,5-diamine-2-iminoimidazolidine with formaldehy de can be controlled to give hexahydroimidazo[4,5-d]imidazole-2(1H)-imine under the c ondition of weak acid.TNINA was synthesized by three stages of nitration reaction us ing hexahydroimidazo[4,5-d]imidazole-2(1H)-imine as material.TNINA and its interme diates were characterized by IR,NMR and MS.The factors effecting nitration reaction were investigated through single factor exp eriments.After optimizing the reaction conditions,in the first nitration step,the yield of hexahydroimidazo[4,5-d]imidazole-2(1H)-imine was about 90%after 60 min’s reactio n at 0 ℃;in the second nitration step,the yield of 4,6-dinitroh-exahydroimidazo[4,5-d]imida zole-2(1H)-imine was85%with n(Ac2O):/n(HNO3)=102:84 for reacting 30 mi ns at 38 ℃;in the third nitration step,for acylatiing 2 h at 100 ℃ and then nitratin g 3 h at 50 ℃,the yield was 72%with V(Ac2O):V(HN03)=3:1.The thermal stability of TNINA was analyzed by DSC and TG.The initial deco mposition temperature is 209.1 ℃ and the peak of decomposition temperature is 214.4℃.Only a very narrow exothermic peak was observed which meant the exothermic p rocess finished instantaneously.The structure of TNINA is optimized by Gaussian 03 with the B3LYP method at 6-31++G(d,p)basis set.The theoretical density of TNINA estimated by the method o f Monte-Carlo is 1.91 g·cm-3.By calculating with the Kamlet-Jacobs equation,heat of detonation of TNINA is 1317.07 cal·g-1,detonation velocity is 8.836 km·s-1,detonation pressure is 35.8 GPa,the value of h50 is 41 cm.All results show that TNINA has b etter detonation properties and sensitivity than RDX.