Gas-phase reactions of OH with methyl amines in the presence or absence of molecular oxygen. An experimental and theoretical study.
Gas-phase reactions of OH with methyl amines in the presence or absence of molecular oxygen. An experimental and theoretical study.
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在存在或不存在分子氧的情况下，OH 与甲胺发生气相反应。
DOI：
10.1021/jp406522z
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Onel L
中科院分区：
文献类型：
--
作者：
Onel L
在298 ~ 1600 K温度范围内，用激光诱导荧光法测定了OH与甲胺（MA）、二甲胺（DMA）、三甲胺（TMA）和乙胺（EA）反应的速率系数。298 K时，在5-25 Torr的氮气浴中，反应速率系数（1011×k/cm ~ 3 molecule ~（-1）s ~（-1））分别为：kOH+MA= 1.97 ± 0.11，kOH +DMA= 6.27 ± 0.63，kOH +TMA= 5.78 ± 0.48，kOH +EA= 2.50 ± 0.13。这些反应都表现出负的温度依赖性，其特征在于：kOH+MA=（1.889 ± 0.053）× 10-11（T/298 K）−（0.56±0.10），kOH+DMA=（6.39 ± 0.35）× 10-11（T/298 K）−（0.75±0.18），kOH+TMA=（5.73 ± 0.15）× 10-11（T/298 K）−（0.71±0.10），kOH +EA=（2.54 ± 0.08）× 10-11（T/298 K）−（0.68±0.10）。OH和OD反应具有非常相似的动力学。在MP2/aug-cc-pVTZ水平上对反应的势能面进行了表征，并改进了CCSD（T）和CCSD（T*）-F12 a计算的稳定点单点能。所有反应的PES的特征在于形成反应前和反应后的复合物和浸没的屏障。计算出的速率系数与实验结果吻合良好;在典型的化学精度范围内，整体速率系数对势垒高度的变化相对不敏感，但分支比变化显著。与MA，DMA和EA的OH/OD的反应的速率系数不随添加的氧而变化，但TMA的速率系数的显着降低观察到从化学活化的过氧自由基的OH再循环一致。OH再生与压力有关，在298 K和大气压下并不显着，但回收效率随着温度的升高而强烈增加。计算了OH循环的PES。有证据表明，TMA在248 nm处光解的主要过程是H原子的损失。
The rate coefficients for the reaction of OH with the alkyl amines: methylamine (MA), dimethylamine (DMA), trimethylamine (TMA), and ethylamine (EA) have been determined using the technique of pulsed laser photolysis with detection of OH by laser-induced fluorescence as a function of temperature from 298 K to ∼600 K. The rate coefficients (1011×k/cm3molecule–1s–1) at 298 K in nitrogen bath gas (typically 5–25 Torr) are:kOH+MA= 1.97 ± 0.11,kOH+DMA= 6.27 ± 0.63,kOH+TMA= 5.78 ± 0.48,kOH+EA= 2.50 ± 0.13. The reactions all show a negative temperature dependence which can be characterized as:kOH+MA= (1.889 ± 0.053) × 10–11(T/298 K)−(0.56±0.10),kOH+DMA= (6.39 ± 0.35) × 10–11(T/298 K)−(0.75±0.18),kOH+TMA= (5.73 ± 0.15) × 10–11(T/298 K)−(0.71±0.10), andkOH+EA= (2.54 ± 0.08) × 10–11(T/298 K)−(0.68±0.10). OH and OD reactions have very similar kinetics. Potential energy surfaces (PES) for the reactions have been characterized at the MP2/aug-cc-pVTZ level and improved single point energies of stationary points obtained in CCSD(T) and CCSD(T*)-F12a calculations. The PES for all reactions are characterized by the formation of pre- and post-reaction complexes and submerged barriers. The calculated rate coefficients are in good agreement with experiment; the overall rate coefficients are relatively insensitive to variations of the barrier heights within typical chemical accuracy, but the branching ratios vary significantly. The rate coefficients for the reactions of OH/OD with MA, DMA, and EA do not vary with added oxygen, but for TMA a significant reduction in the rate coefficient is observed consistent with OH recycling from a chemically activated peroxy radical. OH regeneration is pressure-dependent and is not significant at 298 K and atmospheric pressure, but the efficiency of recycling increases strongly with temperature. The PES for OH recycling have been calculated. There is evidence that the primary process in TMA photolysis at 248 nm is the loss of H atoms.
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影响因子：
14.7
作者：
Seakins PW
通讯作者：
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影响因子：
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作者：
E. C. Tuazon;Pilar Martin;S. M. Aschmann;J. Arey;R. Atkinson
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DOI：
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发表时间：
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期刊：
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影响因子：
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作者：
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