Shock and Detonation Physics Group, Los Alamos National Laboratory , Los Alamos, New Mexico 87545 United States.
J Phys Chem A. 2014 Apr 10;118(14):2559-67. doi: 10.1021/jp4125793. Epub 2014 Mar 31.
Initiation of the shock driven chemical reactions and detonation of nitromethane (NM) can be sensitized by the addition of a weak base; however, the chemical mechanism by which sensitization occurs remains unclear. We investigated the shock driven chemical reaction in NM and in NM sensitized with diethylenetriamine (DETA), using a sustained 300 ps shock driven by a chirped Ti:sapphire laser. We measured the solutions' visible transient absorption spectra and measured interface particle and shock velocities of the nitromethane solutions using ultrafast dynamic ellipsometry. We found there to be a volume-increasing reaction that takes place around interface particle velocity up = 2.4 km/s and up = 2.2 km/s for neat NM and NM with 5% DETA, respectively. The rate at which transient absorption increases is similar in all mixtures, but with decreasing induction times for solutions with increasing DETA concentrations. This result supports the hypothesis that the chemical reaction mechanisms for shocked NM and NM with DETA are the same. Data from shocked NM are compared to literature experimental and theoretical data.
弱碱的加入可以敏化冲击驱动的硝甲烷（NM）化学反应和爆炸，然而，敏化发生的化学机制仍不清楚。我们使用啁啾钛宝石激光持续 300ps 的冲击，研究了 NM 和用二乙烯三胺（DETA）敏化的 NM 的冲击驱动化学反应。我们测量了溶液的可见瞬态吸收光谱，并使用超快动态椭圆测量了硝甲烷溶液的界面颗粒和冲击速度。我们发现，在界面颗粒速度约为 2.4km/s 和 2.2km/s 时，分别在纯 NM 和含 5%DETA 的 NM 中发生了体积增大的反应。在所有混合物中，瞬态吸收增加的速率相似，但随着 DETA 浓度的增加，诱导时间减少。这一结果支持了冲击 NM 和含 DETA 的 NM 的化学反应机制相同的假设。冲击 NM 的实验数据与文献中的实验和理论数据进行了比较。
