The Synthesis And Study Of 4,4',5,5'-tetranitro-2,2'-biimidazole Salts

During the early years,polynitroimidazoles compounds were to be closely watched for their excellent medicinal properties.Reddy Damavaipu found that they were able to be used as melt cast explosive carrier because of their fine explosive performance.Most of the polynitroimidazoles compounds have large ? bond which leads to the fact that these that these compounds have preferable thermal stability and are insensitive to the stimulation from the environment.Such a good property makes them have a positive applying aspect and become potential replacement of the traditional energetic materials.The 4,4',5,5'-tetranitro-2,2'-biimidazole(TNBI)is a kind of derivative of polynitroimidazoles compounds,which keeps a similar energy level and stability with RDX and a relatively low melting point but a strong hygroscopicity.Thus,it is significant to study its synthesis technology and improve its property through its salts.The TNBI came from a two-step synthesis starting with glyoxal.And the TNBI was used to synthesize three different TNBI salts which had been characterized.Firstly,the glyxal and ammonium acetate were used to synthesize TNBI through a twostep process.The TNBI was characterized by IR,1H NMR and MS,while the heat property has also been analyzed.Several factors have been studied relating to the yield of 2,2'-biimidazole including reaction temperature,reaction time and the resource of nitrogen.Orthogonal experiment was used to optimize the synthesis technology and the accepted condition was that the reaction temperature was 40?,reaction time was 4h and the resource of nitrogen was ammonium acetate.The yield of this condition was 48.7%.Several factors have been studied relating to the yield of TNBI including reaction temperature,reaction time n(NaNO3):n(BI)and Nitrification agent.Orthogonal experiment was used to optimize the synthesis technology and the accepted condition was that the reaction temperature was 80?,reaction time was 6h,n(NaNO3):n(BI)was 7:1.The yield under this condition was 58.7% while the total yield of TNBI was 28.6%.Three salts of TNBI including hydrazinium salt,hydroxylaminium salt and guanidnium salt have been successfully synthesized with the ingredients of TNBI,hydrazine hydrochloride,hydroxylamine hydrochloride and Guanidine hydrochloride.The three salts all have been characterized by IR,1H NMR,EA and their heat property has also been analyzed.Several factors have been studied that can influence the yield of TNBI salts including reaction temperature,reaction time,reaction solvent,etc.The yield of hydrazinium salt was 87.1%,hydroxylaminium salt was 79.5% and guanidnium salt was 91.2%.The density of the salts have been characterized in result that the hydrazinium salt was 1.78g/cm3,hydroxylaminium salt was 1.81g/cm3 and guanidnium salt was 1.70g/cm3.The Kamlet method was used to calculate the exploring speed and pressure.The hydrazinium salt was 8454m/s and 30 Gpa,hydroxylaminium salt was 8370m/s and 31 Gpa,guanidnium salt was 7810m/s and 24 Gpa.