Synthesis And Property Study Of DTDA Energetic Complexes

In this article, AHDNE was prepared using FOX-7 as raw material, which can react with many compounds to give new energetic materials due to the strong activity of the adjacent amino-hydrazino group. K?AHDNE? was synthesized using AHDNE as raw material, ancillary ligand was introduced to generate coordination compound Cd?NH₃?₆?AHDNE?2 and Zn?NH₃?₄?AHDNE?2, unexpectedly, the compounds of N'-?2,2-dinitroethlideneamino?-2,2-dinitroacetamidine ?DTDA? were obtained, namely Cd?NH₃?₆?DTDA?-H₂O and Zn?NH₃?₄?DTDA?·H₂O. DTDA is changed from two molecules of AHDNE:in alkali solution, the catalytic action of the alkaline-metal ions makes the hydrazino of adjacent amino-hydrazino in AHDNE leave, forming DNANT. And then DNANT reacts with another AHDNE to give DTDA. Moreover, Zn reacts with K?AHDNE? in ethylenediamine aqueous solution, C=C bond in AHDNE was broken because of the catalytic influence of Zn2+, and the single crystal{K[CH?NO₂?₂]}n was obtained. The structures were determined by X-ray diffractometer.Cd?NH₃?₆?DTDA?·H₂O:monoclinic; P2?1?/c;Zn?NH₃?₄?DTDA?·H₂O:monoclinic; P2?1?/c;{K[CH?NO₂?₂]}n:triclinic; P-1.Combining DSC and TG/DTG curves, thermal behavior of Cd?NH₃?₆?DTDA?·H₂O and {K[CH?NO₂?₂]}n were investigated, apparent activation energy and pre-exponential factor were calculated, and the thermal decomposition dynamic equations were obtained. The continuous specific heat capacity of Cd?NH₃?₆?DTDA?·H₂O and{K[CH?NO₂?₂]}n were determined, and the time-to-explosion of them were calculated. Thermal stability was valued by measuring the impact sensitivity, the impact sensitivity of Cd?NH₃?₆?DTDA?·H₂O was 19.6 J, and that of {K[CH?NO₂?₂]}n was 15.7 J, which was much lower than that of K?AHDNE? ?5 J? but higher than that of K?NNMPA? ?16.7 J?.Moreover, in this article, the constant-volume combustion heat of fourteen kinds of energetic materials including FOX-7 were studied, standard molar enthalpy of combustion and standard molar enthalpy of formation were calculated, the change rule of structure-property was also discussed. Combustion heat tends to rise with the increase of the number of C atoms in molecule. As for FOX-7 and its five closed-loop derivatives, the sequence of combustion heat for the six compounds is DNDH> MDNZ> DNDX> DNDZ> DDNI> FOX-7. The determined specific heat capacity demonstrated that the specific heat capacity decreases with the increase of the number of C atoms in heterocyclic ring ?FOX-7> DNDZ> DNDX> DNDH?, and the change rule of specific heat capacity for these compounds is just contrary to that of their combustion heats. To the isomers, both combustion heat and specific heat capacity follow the same change rule ?MDNZ> DNDX?. The measurement of DNDZ and DDNI show that the introduction of hydroxyl group can markedly decrease the combustion heat and specific heat capacity. Combustion heat of K?DNDZ?, K?AHDNE?, K?FOX-7? and G?FOX-7? also obey the above principle, specific heat capacity of them are higher than that of FOX-7, the effect of K⁺ is smaller than that of G⁺. The study of combustion heat provides rich thermal data to energetic materials.