Secondary channels in the thermal decomposition of monomethylhydrazine (CH3NHNH2)
Secondary channels in the thermal decomposition of monomethylhydrazine (CH3NHNH2)
复制标题
一甲基肼 (CH3NHNH2) 热分解的次级通道
DOI：
--
复制
发表时间：
2014
期刊：
影响因子：
--
通讯作者：
C. Law
中科院分区：
文献类型：
--
作者：
Peng Zhang;S. Klippenstein;L. B. Harding;Hongyan Sun;C. Law
在极低压热解研究中的质谱观察（Golden等人，Int. J. Chem. Kinet.，1972，4，433-448）表明产生NH3和H2及其副产物的分子通道起主导作用。相比之下，最近基于从头算过渡态理论的主方程理论研究（Zhang et al.，程序燃烧。Inst.，2011，33，425-432）表明，简单的N-N和C-N键裂变主导动力学。MMH分子分解通道的可能作用进一步探讨通过额外的调查势能面。这些调查认为三重态通道的作用，漫游自由基通道，和一些以前未探索的分子分解途径。新的基于从头算过渡态理论的主方程计算为MMH分解动力学的温度和压力依赖性提供了修订的预测，与最近的激波管测量结果非常一致（Li等人，Flame，2014，161，16-22）。这些计算仍然表明分子消除通道的贡献非常有限。一个漫游路径建议提供直接形成氨的主要途径。简要讨论了二次抽提反应在超低压热解实验中的可能作用。
Mass spectrometric observations in a very low pressure pyrolysis study (Golden et al., Int. J. Chem. Kinet., 1972, 4, 433–448) of the decomposition of the prototypical rocket fuel monomethylhydrazine (MMH) indicated a dominant role for the molecular channels producing NH3 and H2 and their coproducts. In contrast, a recent ab initio transition state theory based master equation theoretical study (Zhang et al., Proc. Combust. Inst., 2011, 33, 425–432) indicated that simple N–N and C–N bond fissions dominate the kinetics. The possible role of molecular decomposition channels in MMH is explored further through additional investigations of the potential energy surface. These investigations consider the role of triplet channels, of roaming radical channels, and of some previously unexplored pathways for molecular decomposition. New ab initio transition state theory based master equation calculations provide revised predictions for the temperature and pressure dependence of the MMH decomposition kinetics that are in excellent agreement with recent shock tube measurements (Li et al., Comb. Flame, 2014, 161, 16–22). These calculations continue to suggest only a very limited contribution from the molecular elimination channels. A roaming pathway is suggested to provide the dominant route for direct formation of ammonia. The possible role of secondary abstraction reactions in the very-low-pressure pyrolysis experiments is briefly discussed.