Reactions of chlorine atoms with a series of aromatic hydrocarbons.
Reactions of chlorine atoms with a series of aromatic hydrocarbons.
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DOI：
10.1021/es0479437
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发表时间：
2005-06
影响因子：
11.4
通讯作者：
Lin Wang;J. Arey;R. Atkinson
中科院分区：
文献类型：
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作者：
Lin Wang;J. Arey;R. Atkinson
芳烃，包括多环芳烃（PAHs），存在于城市和农村的大气中。多环芳烃与氯原子的反应可能发生在海洋边界层和沿海地区。为了评估这些反应的重要性并研究这些反应是否形成任何独特的含氯产物，我们测量了Cl原子与甲苯-d8、1,3,5-三甲基苯（1,3,5- tmb）、萘、1-甲基萘-d10 （1- mn -d10）、1-和2-甲基萘（1-和2- mn）、1-和2-乙基萘（1-和2- en）以及二甲基萘（DMNs）在296 +/- 2 K下的气相反应的速率常数。用相对速率法测定了Cl原子与1,3,5- tmb的反应速率常数为2.42 × 10(-10) cm3分子（-1）s(-1)，得到的速率常数(以10（-10)cm3分子（-1）s（-1）为单位）为：萘<或= 0.0091 +/- 0.0003；1-mn, 1.21 +/- 0.16；2-mn, 1.05 +/- 0.13；1-en, 2.12 +/- 0.35；2-en, 1.38 +/- 0.27；1,2- dmn, 3.61 +/- 0.68；1,3- dmn, 2.90 +/- 0.22；1,4- dmn, 2.93 +/- 0.30；1,5- dmn, 2.31±0.19；1,6- dmn, 2.15 +/- 0.20；1,7- dmn, 3.05 +/- 0.34；1,8- dmn, 3.07±0.44；2,3- dmn, 2.93 +/- 0.49；2,6- dmn, 2.34 +/- 0.18；2,7- dmn, 2.00 +/- 0.22，其中指示误差为两个标准差，不包括1,3,5- tmb速率常数的不确定性。对甲苯-d8和1-MN-d10反应的氘同位素效应的测量表明，反应是通过初始的H-（或D-）原子抽离进行的。利用气相色谱法和现场直接空气采样常压电离串联质谱法从甲苯和1-MN反应中鉴定和定量的产物是甲苯和1-萘醛（约36%，产率下限）和1-萘醇（约12%，产率下限）的苯甲醛（84% +/- 7%产率）和苯甲醇（11% +/- 2%产率）。这些产物证实，h原子抽离是烷基苯和烷基萘的主要（如果不是唯一）反应途径，这与萘比烷基萘低100倍的反应速率常数和氘同位素效应相一致。
Aromatic hydrocarbons, including polycyclic aromatic hydrocarbons (PAHs), are present in urban and rural atmospheres. Reactions of PAHs with Cl atoms may occur in the marine boundary layer and in coastal regions. To assess the importance of these reactions and to investigate whether any unique chlorine-containing products are formed from these reactions, we have measured the rate constants for the gas-phase reactions of Cl atoms with toluene-d8, 1,3,5-trimethylbenzene (1,3,5-TMB), naphthalene, 1-methylnaphthalene-d10 (1-MN-d10), 1- and 2-methylnaphthalene (1- and 2-MN), 1- and 2-ethylnaphthalene (1- and 2-EN), and the dimethylnaphthalenes (DMNs) at 296 +/- 2 K. A relative rate technique was used, and, using our measured rate constant forthe reaction of Cl atoms with 1,3,5-TMB of 2.42 x 10(-10) cm3 molecule(-1) s(-1), the rate constants (in units of 10(-10) cm3 molecule(-1) s(-1)) are as follows: naphthalene, < or = 0.0091 +/- 0.0003; 1-MN, 1.21 +/- 0.16; 2-MN, 1.05 +/- 0.13; 1-EN, 2.12 +/- 0.35; 2-EN, 1.38 +/- 0.27; 1,2-DMN, 3.61 +/- 0.68; 1,3-DMN, 2.90 +/- 0.22; 1,4-DMN, 2.93 +/- 0.30; 1,5-DMN, 2.31 +/- 0.19; 1,6-DMN, 2.15 +/- 0.20; 1,7-DMN, 3.05 +/- 0.34; 1,8-DMN, 3.07 +/- 0.44; 2,3-DMN, 2.93 +/- 0.49; 2,6-DMN, 2.34 +/- 0.18; and 2,7-DMN, 2.00 +/- 0.22, where the indicated errors are two standard deviations and do not include the uncertainty in the rate constant for 1,3,5-TMB. The measured deuterium isotope effects for the toluene-d8 and 1-MN-d10 reactions indicate that the reactions proceed by initial H- (or D-) atom abstraction. The products identified and quantified from the toluene and 1-MN reactions using gas chromatography and in situ direct air sampling atmospheric pressure ionization tandem mass spectrometry were benzaldehyde (84% +/- 7% yield) and benzyl alcohol (11% +/- 2% yield) from toluene and 1-naphthaldehyde (approximately 36%, lower limit to yield) and 1-naphthyl alcohol (approximately 12%, lower limit to yield) from 1-MN. These products confirm that H-atom abstraction is the dominant, if not sole, reaction pathway for the alkylbenzenes and alkylnaphthalenes, consistent with the 100-fold lower rate constant measured for naphthalene compared to the alkylnaphthalenes and with the measured deuterium isotope effects.