Rate constants for the reactions of C2H5, C2H5O and C2H5O2 radicals with NO3 at 298 K and 2.2 torr
Rate constants for the reactions of C2H5, C2H5O and C2H5O2 radicals with NO3 at 298 K and 2.2 torr
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C2H5、C2H5O 和 C2H5O2 自由基与 NO3 在 298 K 和 2.2 torr 下反应的速率常数
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
R. Wayne
中科院分区：
文献类型：
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作者：
P. Biggs;Carlos E. Canosa;J. Fracheboud;D. Shallcross;R. Wayne
采用激光诱导荧光细胞检测乙氧基自由基和光学吸收细胞检测硝酸盐自由基的放电-流动系统，测定了温度为298 K， P= 2.2 Torr条件下，C2H5+ NO3→产物(1)、C2H5O + NO3→产物(2)、C2H5O2+ NO3→产物(3)的反应速率常数。这些反应的主要产物是反应(1)的C2H5O和NO2，反应(2)的C2H5O2和NO2，反应(3)的C2H5O、O2和NO2。因此，反应(2)和(3)是高度耦合的，为了确定这些反应的速率常数k2和k3，进行了两种类型的实验。在第一组实验中，通过反应(1)原位生成C2H5O并与NO3反应，在第二组实验中，单独生成C2H5O2并与NO3反应。利用数值模型推导出以下速率常数：k1=（4.0±1.0）× 10-11 cm3分子- 1 s-1， k2=（3.5±1.0）× 10-12 cm3分子- 1 s-1， k3=（2.5±1.5）× 10-12 cm3分子- 1 s-1。所引用的误差不是统计得出的，而是表示数值模拟与实验数据充分拟合的范围。从QRRK处理的角度讨论了反应(1)和(2)的机理，并考虑了反应(3)的大气影响。
A discharge-flow system equipped with a laser-induced fluorescence cell to detect the ethoxyl radical and an optical absorption cell to detect the nitrate radical has been used to measure the rate constants for the reactions C2H5+ NO3→ products (1), C2H5O + NO3→ products (2), C2H5O2+ NO3→ products (3), at T= 298 K and P= 2.2 Torr. The major products of these reactions are C2H5O and NO2 for reaction (1), C2H5O2 and NO2 for reaction (2) and C2H5O, O2 and NO2 for reaction (3). Reactions (2) and (3) are therefore highly coupled and, in order to determine the rate constants k2 and k3 for these reactions, two types of experiment were performed. In the first set of experiments, C2H5O was generated in situ via reaction (1) and allowed to react with NO3 and, in the second set of experiments, C2H5O2 was generated separately and allowed to react with NO3. A numerical model was then used to derive the following rate constants : k1=(4.0 ± 1.0)× 10–11 cm3 molecule–1 s–1, k2=(3.5 ± 1.0)× 10–12 cm3 molecule–1 s–1 and k3=(2.5 ± 1.5)× 10–12 cm3 molecule–1 s–1. The errors quoted are not statistically derived, but rather represent ranges over which the numerical simulations fit the experimental data adequately. The mechanisms for reactions (1) and (2) are discussed in terms of the QRRK treatment and the atmospheric implications of reaction (3) are considered.