3,5-Dinitropyrazole was prepared via four steps: nitration,σ-rearrangement,nitration andσ-rearrangement, using pyrazole as a raw material. Pyrazole was nitratedby the mixture acid,mixture of nitric acid and acetic anhydride,N2O5/organic solutionsystem, in the phase of nitration and further nitration. Nitric acid and acetic anhydridenitrition system, we mostly adopt the method reported, of which the yield hadincreased significantly to 60% and 68.2% respectively, compared with 49% and 57%reported. The increasing of nitration efficiency is attributed to the certain improvementon the conditions of the two nitration steps. In the N2O5/organic inert solution system,by inspected in the different systems,separately. The nitration and further nitration wastook place in 100% nitric acid, organic inert solution and organic inert solution/ionicliquid system with N2O5, which is a clean nitrating agent. As a result, the yield of thefirst nitration is 75%~85% with the temperature controlled around 0℃, while thesecond nitration is 70%~75%, around 20℃. By the catalysis of ionic liquid(TMPSHSO4), the nitration efficiency and the reaction speed of the nitration inN2O5/organic solution system had been improved respectively. Specifically, thenitration efficiency is close to N2O5/nitric acid system, and keep the selectiveadvantage as well, meanwhile, the influence of organic solution polarity iscounteracted. The temperature of rearrangement reaction was controlled between185~195℃, utilizing benzophenone, n-octano, beneonitrile as the solvent. The structureof the final product was confirmed by 1HNMR, IR and MS.
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