Improvement Of The Synthetically Process Of 2,6-Diamino-3,5-Dinitropyrazine-1-Oxide

The new synthetically process of the new insensitive energetic material 2,6-diamino-3,5-dinitropyrazine-l-oxide (LLM-105) was investigated.2,6-dichloropyrazine as starting materials, the synthetic route has four steps:substitution, nitration, amination, and oxidation in turn, the overall yield of LLM-105 is up to 54%. Investigated the effects of methoxylation reaction, the different nitration system, the different amination system and the volume proportion of trifluoroacetic acid and hydrogen peroxide on the total yield of LLM-105. Optimize the synthesis conditions and the best process conditions.(1)Methoxylation of 2,6-dichloropyrazine to 2,6-dimethoxypyrazine.2,6-dimethoxypy-razine is a solid at room temperature, easy to dry, undergo nitration at room temperature. The best process conditions:25% sodium methoxidc methanol solution,250% of the amount of sodium methoxid, reflux 3h. (2) Nitrated 2,6-dimethoxypyrazine to 2,6-dimethoxy-3,5-dinitro pyrazine undergo 20% oleum and potassium nitrate nitration system. The best process conditions:the mass ratio of 20% fuming sulfuric acid and 2,6-dimethoxypyrazine is 11.4:1, the molar ratio of Potassium nitrate and 2,6-dimethoxypyrazine is 5:1, reaction conditions at room temperature for 3h,68.2% yield. (3) Aminated 2,6-dimethoxy-3,5-dinitropyrazine to 2,6-dimethoxy-3,5-dinitropyrazine, protic solvent ethyl alcohol as ammoniated solvent. The best process conditions:the mass ratio of Ethanol and 2,6-dimethoxy-3,5-dinitropyrazine is 16:1, under the reaction conditions of 60℃,2h,97% yield. (4) Oxidized 2,6-Diamino-3,5-dinitropyrazine (ANPZ) to LLM-105. The best process conditions:the mass ratio of Trifluoroacetic acid and ANPZ is 23:1, the volume ratio of trifluoroacetic acid and 30%hydrogen peroxide is 3:2, reaction conditions 45℃,6h,88.9%yield. We scale-up the synthesis of LLM-105 to the 70g and 140g scale find the yield had a slight increase, up to 91.4% and 92.0% respectively.We try to recycle trifluoroacetic acid in the synthesis process of LLM-105, but the result is not satisfactory. Trifluoroacetic acid accounted for half of the cost of in the synthesis process of LLM-105, so the recycle is with high economic value. Besides we also tried to investigate new synthetic route of LLM-105, three new synthetic routes were designed, but all failed.