Thermal Stability and Explosive Hazard Assessment of Diazo Compounds and Diazo Transfer Reagents
Thermal Stability and Explosive Hazard Assessment of Diazo Compounds and Diazo Transfer Reagents
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DOI：
10.1021/acs.oprd.9b00422
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发表时间：
2020-01-01
影响因子：
3.4
通讯作者：
Bull, James A.
中科院分区：
文献类型：
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作者：
Green, Sebastian P.;Wheelhouse, Katherine M.;Bull, James A.
尽管重氮化合物在学术界广泛用作金属卡宾前体，但由于担心其不稳定性、放热分解和潜在的爆炸行为，工业上通常避免使用重氮化合物。磺酰叠氮和其他重氮转移试剂的稳定性相对较好理解，但几乎没有关于重氮化合物的可靠数据。这项工作首先整理了重氮转移试剂和重氮化合物的灵敏度和热分析数据，作为一个可访问的参考资源。本文给出了模型给体/受体重氮化合物（苯基）-重氮乙酸乙酯的热重分析（TGA）、差示扫描量热法（DSC）和加速速率量热法（ARC）数据。我们还提供了一个严格的DSC数据集，其中包含43种其他重氮化合物，可以与其他高能材料进行直接比较，为学术和工业化学界提供明确的参考工作。有趣的是，这一系列化合物的起始温度（T-onset）范围很广，在75至160摄氏度之间变化。热稳定性的变化取决于取代基的电子效应和电荷离域量。建立了预测不同取代基重氮乙酸苯酯热稳定性的统计模型。对于选定的重氮化合物，估计了避免分解的最大推荐工艺温度（T-D24）。重氮化合物的平均分解焓（Δ H-D）为-102 kJ mol（-1）。使用相同的DSC方案分析了几种重氮转移试剂，发现它们具有更高的热稳定性，这与报道的值基本一致。对于磺酰叠氮试剂，观察到平均Δ H-D为-201 kJ mol（-1）。ARC实验的高质量热数据显示，（苯基）重氮乙酸乙酯的分解起始温度为60 ℃，而常见的重氮转移试剂对乙酰氨基苯磺酰叠氮（p-ABSA）的分解起始温度为100 ℃。吉田的相关性适用于DSC数据为每一个重氮化合物，以提供一个指标，他们的撞击感度（IS）和爆炸性。作为纯物质，没有一种测试的重氮化合物预计会爆炸，但许多重氮化合物（特别是供体/受体重氮化合物）预计会对撞击敏感。因此，建议对纯重氮化合物进行操作、搅拌和其他处理时应适当小心，以避免影响，特别是大量处理时。提供完整的数据集，以告知化学家使用重氮化合物和重氮转移试剂时的危害性质和程度。考虑到已证实的快速发热和气体释放的潜力，强烈建议在与重氮化合物进行反应时，充分控制温度并谨慎加入开始反应的试剂。
Despite their wide use in academia as metal-carbene precursors, diazo compounds are often avoided in industry owing to concerns over their instability, exothermic decomposition, and potential explosive behavior. The stability of sulfonyl azides and other diazo transfer reagents is relatively well understood, but there is little reliable data available for diazo compounds. This work first collates available sensitivity and thermal analysis data for diazo transfer reagents and diazo compounds to act as an accessible reference resource. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and accelerating rate calorimetry (ARC) data for the model donor/acceptor diazo compound ethyl (phenyl)-diazoacetate are presented. We also present a rigorous DSC dataset with 43 other diazo compounds, enabling direct comparison to other energetic materials to provide a clear reference work to the academic and industrial chemistry communities. Interestingly, there is a wide range of onset temperatures (T-onset) for this series of compounds, which varied between 75 and 160 degrees C. The thermal stability variation depends on the electronic effect of substituents and the amount of charge delocalization. A statistical model is demonstrated to predict the thermal stability of differently substituted phenyl diazoacetates. A maximum recommended process temperature (T-D24) to avoid decomposition is estimated for selected diazo compounds. The average enthalpy of decomposition (Delta H-D) for diazo compounds without other energetic functional groups is -102 kJ mol(-1). Several diazo transfer reagents are analyzed using the same DSC protocol and found to have higher thermal stability, which is in general agreement with the reported values. For sulfonyl azide reagents, an average Delta H-D of -201 kJ mol(-1) is observed. High-quality thermal data from ARC experiments shows the initiation of decomposition for ethyl (phenyl)diazoacetate to be 60 degrees C, compared to that of 100 degrees C for the common diazo transfer reagent p-acetamidobenzenesulfonyl azide (p-ABSA). The Yoshida correlation is applied to DSC data for each diazo compound to provide an indication of both their impact sensitivity (IS) and explosivity. As a neat substance, none of the diazo compounds tested are predicted to be explosive, but many (particularly donor/acceptor diazo compounds) are predicted to be impact-sensitive. It is therefore recommended that manipulation, agitation, and other processing of neat diazo compounds are conducted with due care to avoid impacts, particularly in large quantities. The full dataset is presented to inform chemists of the nature and magnitude of hazards when using diazo compounds and diazo transfer reagents. Given the demonstrated potential for rapid heat generation and gas evolution, adequate temperature control and cautious addition of reagents that begin a reaction are strongly recommended when conducting reactions with diazo compounds.