A SHOCK-TUBE INVESTIGATION OF MAJOR PATHWAYS IN THE HIGH-TEMPERATURE PYROLYSIS OF BENZENE
A SHOCK-TUBE INVESTIGATION OF MAJOR PATHWAYS IN THE HIGH-TEMPERATURE PYROLYSIS OF BENZENE
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DOI：
10.1021/j100256a043
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发表时间：
1985-01-01
影响因子：
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通讯作者：
WEI, HC
中科院分区：
文献类型：
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作者：
KIEFER, JH;MIZERKA, LJ;WEI, HC
在激波管中，用激光纹影技术研究了1mol%和2mol%苯在氪气中的高温热解，温度范围为1900-2400 K，压力范围为0.2- 1.0atm。一个完全成功的建模的密度梯度分布和一些飞行时间质谱实现了一个简单的自由基链机制，基本上只包括四个反应。在此温度范围内，解离反应仅为CH键断裂（）+C6 H6-* C6 H5 ++（M），其速率与温度和压力密切相关，当温度> 2300 K时，该反应接近二级反应。对这些数据的RRKM拟合表明112± 2kcal/mol的势垒，其对应于苯基自由基生成热的Δ Hfm = 80± 2kcal/mol，并且平均碰撞能量转移（-Δ E）all= 70 cm-1。该反应的外推值为2 × 1017 exp（~ 118000（cal）/RT）s-1（1900-2400 K）。该模型还表明，H+ C6 H6-C6 H5 + H2的抽提速率常数为2.5 × 10 ~（14）exp（-16000（cal）/RT）cm ~ 3/（mol·s）（1900-2200 K）。苯在燃料、裂解烯烃的产物和原料中普遍存在，因此苯的裂解具有明显的重要性。芳环还具有独特的稳定性，并且很可能在烟灰形成中起主要作用。1因此，这种热解已经在相当广泛的条件下通过各种方法进行了广泛的研究。
The high-temperature pyrolysis of benzene, 1 and 2 mol% in krypton, has been studied in the shock tube with the laser-schlieren technique over 1900-2400 K and 0.2-1.0 atm. A completelysuccessful modeling of the density gradient profiles and some time-of-flight mass spectra is achieved with a simple radical chain mechanism consisting of essentially just four reactions. The dissociation is solely CH bond scission ()+ C6H6-* C6H5++(M) whose rates are strongly dependent on both temperature and pressure in this range; this reaction is near second order for T> 2300 K. An RRKM fit to these data suggests a barrier of 112±2 kcal/mol, which corresponds to AHfm= 80±2 kcal/mol for the phenyl radical heat of formation, and an average collisional energy transfer of (-AE) all= 70 cm" 1 11. The extrapolated for this reaction is 2 X 1017 exp (-l 18000 (cal)/RT) s" 1 (1900-2400 K). The model also indicates a rate constant of 2.5 X 1014 exp (-16000 (cal)/RT) cm3/(mol s)(1900-2200 K) for the abstraction H+ C6H6— C6H5+ H2.Benzene pyrolysis hasan obvious importance derivingfrom the molecule’s common appearance in fuels, as well as in the products and feedstocks of pyrolytic olefin production. The aromatic ring also carries a unique stability and may well play a major role in soot formation. 1 As a consequence this pyrolysis has been ex-tensively studied over a rather broad range of conditions and by a variety of methods.