Study on Nitration Technology of 2,6-Diamino-3,5-dinitropyrazine

The nitration reaction process for the synthesis of 2,6-diamino-3,5-dinitropyrazine was investigated using 2,6-dinmethoxypyrazine as raw material under different nitration systems including mixed acid system,oleum-nitric acid system and oleum-KNO3system.The effect of mixed acid ratio,reaction time and reaction temperature on the yield of nitration reaction product were explored.The optimal process conditions of the nitration were detemined as reaction temperature 25℃,reaction time 3h,20%oleum-KNO3system(the molar ratio is 3.5∶1)in which KNO3 is in excess of 100%and the dosage of 2,6-dimethoxypyrazine 0.1mol.Under these conditions,the yield of 2,6-dimethoxy-3,5-dinitropyrazine is 67.8%.