The rate constant of the reaction NCN + H2 and its role in NCN and NO modeling in low pressure CH4/O2/N2-flames.
The rate constant of the reaction NCN + H2 and its role in NCN and NO modeling in low pressure CH4/O2/N2-flames.
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NCN H2 反应的速率常数及其在低压 CH4/O2/N2 火焰中 NCN 和 NO 建模中的作用
DOI：
10.1039/c5cp01414j
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
G. Friedrichs
中科院分区：
文献类型：
--
作者：
N. Faßheber;N. Lamoureux;G. Friedrichs
NCN自由基的双分子反应在模拟烃类火焰中迅速生成no的过程中起着关键作用。在伪一阶激波条件下，以H2为过量组分，实验确定了NCN + H2反应的速率常数。利用NCN3热分解作为NCN自由基的定量高温源，在= 30383.11 cm−1处用差紫外激光吸收光谱对NCN3自由基进行了灵敏探测。实验在ρ≈4.1 × 10−6 mol cm−3和ρ≈7.4 × 10−6 mol cm−3两种不同的总密度下进行（对应于p = 324 mbar和p = 1665 mbar之间），发现了一个不受压力影响的反应。在1057 K < T < 2475 K的温度范围内，总速率常数可表示为：K /(cm3 mol−1 s−1)= 4.1 × 1013 exp(- 101 kJ mol−1/RT) （Δlog K =±0.11）。不依赖压力的反应和测量的活化能与主要的H提取反应通道一致，生成产物HNCN + H。NCN + H2反应与随后HNCN和HNC化学的一系列反应一起被实现到详细的GDFkin3.0_NCN机理中，用于NOx火焰建模。以两种富燃料低压CH4/O2/ n2火焰为例，量化了附加化学途径的影响。尽管H2的总体NCN消耗仍然很小，但在更新的机制下，NO的产量已经观察到显著差异。详细的通量分析表明，HNC主要由HCN/HNC异构化产生，并通过HNC→HNCO→NH2→NH→NO的新途径促进NO的形成。
Bimolecular reactions of the NCN radical play a key role in modeling prompt-NO formation in hydrocarbon flames. The rate constant of the so-far neglected reaction NCN + H2 has been experimentally determined behind shock waves under pseudo-first order conditions with H2 as the excess component. NCN3 thermal decomposition has been used as a quantitative high temperature source of NCN radicals, which have been sensitively detected by difference UV laser absorption spectroscopy at = 30383.11 cm−1. The experiments were performed at two different total densities of ρ ≈ 4.1 × 10−6 mol cm−3 and ρ ≈ 7.4 × 10−6 mol cm−3 (corresponding to pressures between p = 324 mbar and p = 1665 mbar) and revealed a pressure independent reaction. In the temperature range 1057 K < T < 2475 K, the overall rate constant can be represented by the Arrhenius expression k/(cm3 mol−1 s−1) = 4.1 × 1013 exp(−101 kJ mol−1/RT) (Δlog k = ±0.11). The pressure independent reaction as well as the measured activation energy is consistent with a dominating H abstracting reaction channel yielding the products HNCN + H. The reaction NCN + H2 has been implemented together with a set of reactions for subsequent HNCN and HNC chemistry into the detailed GDFkin3.0_NCN mechanism for NOx flame modeling. Two fuel-rich low-pressure CH4/O2/N2-flames served as examples to quantify the impact of the additional chemical pathways. Although the overall NCN consumption by H2 remains small, significant differences have been observed for NO yields with the updated mechanism. A detailed flux analysis revealed that HNC, mainly arising from HCN/HNC isomerization, plays a decisive role and enhances NO formation through a new HNC → HNCO → NH2 → NH → NO pathway.
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影响因子：
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作者：
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DOI：
10.1021/acs.jpca.5b01347
发表时间：
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期刊：
The journal of physical chemistry. A
影响因子：
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