The Synthesis And Study Of Nitro Derivatives In Imidazole And Biimidazole

High-nitrogen energetic materials have the very high enthalpy, for they have a lot of high-energy chemical bonds, such as N-N, C=N and C-N. To some extent, heterocyclic ring hasstability. Modification in the base of heterocyclic has become another source of potentialenergy. Imidazole has five rings which contains C-N heterocycle. We can get a series ofnitroimidazole derivatives by nitrify imidazole, such as1,4-DNI,2,4-DNI,4,5-DNI,2,4,5-TNI and so on. But during the process of preparation, we found that2-nitroimidazole is one ofthe most difficult to prepare. For this situation, our article reports that making the biimidazole.In the process of preparation biimidazole, we check out the existence of2-amino-imidazoles and optimize the synthetic process. It avoids the difficulty of nitrification of thesecond place of the imidazole, as bisimidazole is connected by2,2′of carbon atom. We triedto use different nitrating agent and got1,1′-bisnitroimidazole and4,4′,5,5′-tetranitro-imidazole.In the first place, control the reaction condition, mixing the guanidine hydrochloride withoxalaldehyde, we can get crystal from glacial acetic acid. Target product: the sulphate of2-aminoimidazoles, melting point,268~277℃. The structure of2-aminoimidazole wascharacterized by IR and NMR spectroscopy and mass spectrometry. We optimize of thesynthesis of it, but the overall rate is still relatively low (about7％). It limits the change ofamino to nitro.Mixing oxalaldehyde with ammonia, we can get the target product bisimidazole. Putting itinto DMSO to recryst, then, gets the white needle crystal. The synthesized compounds werecharacterized by IR and NMR spectroscopy, mass spectrometry, and CHN analysis. Weexplore the effects of different factors on the yield. The optimum synthetic condition isT=35℃and t=4h. And the yield is60.8％. The biimidazole was performed in a mixed nitric acid and acetic anhydride conditionwhich are a weak nitrating agents. Control the reaction conditions, we can get some faintyellow1,1′-dinitroimidazole. The products were characterized by IR and NMR spectroscopy,mass spectrometry, and CHN analysis. We explore the effects of different factors on the yield.The optimum synthetic condition is T=60℃, t=6h, n（HNO3）：n（Bi）=3.6，and the yield is44.6%.The biimidazole was performed in a mixed nitric acid, sulphuric acetic condition. Keepthe reaction mixture at120℃at all times for about8h. Then, place the reaction mixture intoan ice bath, we can get some pale yellow solid. The products were characterized by IR andNMR spectroscopy, mass spectrometry, and CHN analysis. It is4,4′,5,5′-tetranitroimidazole.We explore the effects of different factors on the yield. The optimum synthetic condition is T=120℃, t=8h, n（HNO3）: n（Bi）=3.6, sodium nitrate18g. The yield can be up to58.7%.