3,5-二硝基吡唑的合成工艺研究

Synthesis of 3,5-dinitropyrazole

以3-硝基吡唑为原料,经过发烟硝酸-乙酸酐体系硝化、邻二氯苯重排、乙醚提纯制备3,5-二硝基吡唑。考察了硝化和重排两步反应的条件,得出硝化的最佳工艺条件为:n(3-硝基吡唑)∶n(发烟硝酸)∶n(乙酸酐)=1∶1.5∶2.25,反应温度50℃,反应时间4 h,得率85.9%;重排工艺的最佳工艺条件为:重排试剂为邻二氯苯,重排温度为170℃,重排时间8 h,乙醚对重排产物提纯,得率78.3%。用较佳的高效液相色谱条件对工艺中各产物的纯度进行了鉴定。

3,5-Dinitropyrazole was prepared by the nitration of 3-nitropyrazole with fuming nitric acid-acetic anhydride,rearrangement with o-dichlorobenzene,purification with ether. The conditions of the nitration and rearrangement were investigated. The optimum conditions of nitration were： n（ 3-nitropyrazole） ∶ n（ fuming nitric acid） ∶ n（ acetic anhydride） = 1∶ 1. 5∶ 2. 25,reaction temperature 50 ℃,reaction time 4 h,yield 85. 9%. The optimum conditions for the rearrangement process were： rearrangement reagent o-dichlorobenzene,rearrangement temperature 170 ℃,rearrangement time 8 h,yield 78. 3%. The purity of each product in the process was identified by better HPLC conditions.