Pyrolysis of acetylene behind reflected shock waves
Pyrolysis of acetylene behind reflected shock waves
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反射冲击波后乙炔的热解
DOI：
10.1002/kin.550191104
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发表时间：
1987
影响因子：
1.5
通讯作者：
R. D. Kern
中科院分区：
文献类型：
--
作者：
C. Wu;H. Singh;R. D. Kern
使用与飞行时间质谱仪耦合的激波管，在 1900–2500 K 和 0.3–0.55 atm 的温度和压力范围内研究了乙炔的热分解。一系列在 Ne-Ar 混合物中稀释的 1.0–6.2% C2H2 混合物在反射激波区产生了 0.24–2.0 × 1017 个原子 cm−3 的碳原子密度范围。 C2H2、C4H2 和 C6H2 的浓度分布是在 750 μs 的典型观察时间内构建的。在本研究的高温结束时，发现 C8H2 和痕量 C4H3 的浓度相对较低。提出了一种乙炔热解机制，该机制成功地模拟了这项工作以及其他几个小组采用各种分析技术获得的结果。建模过程中采用了两个 C2H 生成热值（134 ± 2 和 127 ± 1 kcal/mol）；使用后一个值获得了对数据的更好拟合。乙炔分解的第一步涉及两个通道之间的竞争。在混合物 ( 200 ppm ) 中，主要的初始步骤是二级反应。二级反应的速率常数由以下方程描述
模型预测的苯浓度低于 TOF 可检测限。根据所提出的机制，在 6.2% C2H2 混合物中观察到了 C4H3。
The thermal decomposition of acetylene has been studied in the temperature and pressure regimes of 1900–2500 K and 0.3–0.55 atm using a shock tube coupled to a time-of-flight mass spectrometer. A series of mixtures varying from 1.0–6.2% C2H2 diluted in a Ne-Ar mixture yielded a carbon atom density range of 0.24–2.0 × 1017 atoms cm−3 in the reflected shock zone. Concentration profiles for C2H2, C4H2, and C6H2 were constructed during typical observation times of 750 μs. C8H2 and trace amounts of C4H3 were found in relatively low concentrations at the high-temperature end of this study. A mechanism for acetylene pyrolysis is proposed, which successfully models this work and the results obtained by several other groups employing a variety of analytical techniques. Two values of the heat of formation for C2H(134 ± 2 and 127 ± 1 kcal/mol) were employed in the modeling process; superior fits to the data were attained using the latter value. The initial step of acetylene decomposition involves competition between two channels. In mixtures ( 200 ppm, the dominant initial step is second order. The rate constant for the second-order reaction is described by the equation
Benzene concentrations predicted by the model are below the TOF detectability limit. C4H3 was observed in the 6.2% C2H2 mixture in accordance with the proposed mechanism.