Study On Synthesis And Process 1,1-Diamino-2,2-dinitroethylene (FOX-7)

1,1-Diamino-2,2-dinitroethylene(FOX-7) was a new energetic materials, which had large explosive power,low sensitivity and good chemical stability. It had been attracting widespread attention since it was synthesized for the first time in 1998.Among all the papers published, three preparation methods had reported, however, during the nitrification process, large amounts of acid was needed, strict requirements for temperature were necessary and large waste acid was produced. Therefore, it was important to search an efficient and stable nitrification system to synthesis FOX-7.Mixed acid was a commonly nitrification system used for nitrification. It had strong nitrification ability and could selective nitration by changing conditions, but the reaction was often very violent which could prone to danger. In the paper, FOX-7 was prepared from acetamidine hydrochloride and diethyl malonate by condensation, nitration and hydrolysis. The conditions of condensation and nitration process were optimized.The conditions of synthesis of 2-methylpyrimidine-4,6-dione process were as follows: Reaction time was 3 h, the molar ratio of acetamidine hydrochloride and diethyl malonate was 1:1, the reaction temperature was 90℃. The yield was 91.2%.The improved nitration conditions with mixed acid were as follows:the molar ratio of concentrated sulfuric acid and substrate was 9:1, the volume ratio of organic solvents and concentrated sulfuric acid 1:1, the reaction time was 3 h, the reaction temperature was 10℃, the highest yield was 89.6%.FOX-7 was obtained for the first time by using N2O5-cncentrated sulfuric system. The optimal conditions were as follows:Nitrating agent was N2O5-CH2Cl2, the molar ratio of N2O5 and 2-methyl-pyrimidine-4,6-dione was 2:1, the molar ratio of concentrated sulfuric acid and 2-methyl-pyrimidine-4,6-dione was 9:1, the reaction temperature was 10℃. reaction time was 2 h, the highest yield was up to 86.7%.The structures of the synthetic products were characterized by Mass Spectra (M S).Infrared Spectroscopy (IR) and 1H Nuclear Magnetic Resonance (1HNMR).The results proved that the structures of the products conformed to the design requirement.