高固含量NTO的连续流合成及性能表征

Continuous Flow Synthesis and Characterization of NTO with High Solid Content

为改善3-硝基-1,2,4-三唑-5-酮(NTO)釜式硝化工艺的高放热安全风险、间歇合成效率低的问题,依据NTO硝化合成不同阶段的反应体系特点与动力学特征,设计了针对高固含量体系的连续流反应装置系统。以2,4-二氢-1,2,4-三唑-5-酮(TO)为原料,结合微通道反应技术与管式反应技术实现了NTO连续流合成,并优化了连续流合成工艺条件及装置。在硝化反应温度为45℃、反应停留时间为9 min,物料摩尔比n(TO):n(HNO_(3))=1:6的条件下,以81.4%的收率合成了NTO,纯度99.53%。利用核磁(NMR)、元素分析(EA)、红外(FTIR)等结构分析方法确认了合成产物结构,采用粉末X射线衍射(XRD)、热质联用(TG-DSC)、BAM感度仪、偏光显微镜对连续流合成产物和釜式合成产物进行了性能表征与对比。结果表明,在10℃·min^(-1)的升温速率下,其热分解峰温为276.23℃,热分解过程质量损失为85.12%,撞击感度大于40 J,摩擦感度大于360 N。与釜式合成NTO相比,连续流合成NTO的热分解峰温提高2.95℃,热分解过程质量损失增加4.44%,撞击与摩擦感度相当,晶体形貌规整、粒度分布更均一。连续流合成时间较釜式工艺缩短90%,收率较釜式工艺提高3.4%,制备效率与安全性有所提高。

To improve the thermal safety and synthetic efficiency during the synthesis process of 3⁃Nitro⁃1,2,4⁃triazol⁃5⁃one(NTO)by conventional methods,a continuous flow reaction system was designed and prepared based on the solid contents and kinetics at different reaction stages of nitration.The continuous flow synthesis of NTO was realized by combining microflu⁃idic reaction technology with tubular reaction technology,using 2,4⁃dihydro⁃1,2,4⁃triazol⁃5⁃one(TO)and 85%nitric acid as the main raw materials.The reaction conditions and continuous flow system were optimized.NTO with a purity of 99.53%and a yield of 81.4%was achieved at a reaction temperature of 45℃,a nitration residence time of 9 min,a molar ratio of n(TO)∶n(HNO_(3))equals 1∶6.The chemical structure of NTO synthesized by the continuous flow method was characterized by 1H and 13C NMR,element analysis(EA),infrared spectroscopy(FT⁃IR).In addition,the crystal form,particle morphology,thermal stability and mechanical sensitivity were characterized by the powder X⁃ray diffraction(XRD),thermal analyzer(DSC⁃TG),optical microscope and BAM technology.The results show that NTO grows into stableβ⁃form.At the heating rate of 10℃·min^(-1),the thermal decomposition peak temperature is 276.23℃and the mass loss rate during thermal decomposition is 85.12%.The impact sensitivity is over 40 J,and the friction sensitivity is over 360 N.Compared with NTO synthesized by the flask method,the thermal decomposition peak temperature is increased by 2.95℃,and the mass loss rate is elevated by 4.44%.The mechanical sensitivities is similar,the crystal morphology is regular and the particle size distribution range is narrowed.The continuous flow synthesis time is 90%shorter than that of the flask process,with 3.4%higher of the yiel,and the preparation ef⁃ficiency and safety are improved.