Temperature and pressure dependent kinetics of the gas‐phase reaction of the hydroxyl radical with nitrogen dioxide
Temperature and pressure dependent kinetics of the gas‐phase reaction of the hydroxyl radical with nitrogen dioxide
复制标题
羟基自由基与二氧化氮气相反应的温度和压力依赖性动力学
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
K. Demerjian
中科院分区：
文献类型：
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作者：
T. Dransfield;K. K. Perkins;N. Donahue;James G. Anderson;M. Sprengnether;K. Demerjian
OH与NO2的反应在平流层和对流层化学中都是关键的；在每种情况下，它都是NOx转化为NOy的主要均相机制。速率常数是压力和温度的强烈函数，而压力-温度域的关键部分在现有数据中很少或含糊不清。这些条件包括对流层边界层和平流层下层的典型条件。在地表条件下，文献数据和主要推荐值之间存在60%的差异，而在较低的平流层条件下，可用的数据很少。我们的高压流动动力学系统非常适合研究这种反应，因为我们能够在保持无壁条件下扫描温度和压力，消除非均相化学的可能并发症。在这里，我们报告了该反应的温度和压力依赖性研究（220-300 K, 50-150 torr）；测量的速率常数与之前公布的240 K以下的值非常吻合，但比该温度以下的历史数据低10-20%。对所有可用数据的分析促使对室温以下的推荐速率常数进行大幅度（~ 20%）向下修正。
The reaction of OH with NO2 is pivotal in both stratospheric and tropospheric chemistry; in each case it is the dominant homogeneous mechanism for conversion of NOx to NOy. The rate constant is a strong function of pressure and temperature, and key portions of the pressure‐temperature domain are poorly or ambiguously covered by the available data. These include conditions typical of the tropospheric boundary layer and of the lower stratosphere. At surface conditions differences of 60% exist both in the literature data and between the major recommendations, while at lower stratospheric conditions there are few available data. Our High Pressure Flow kinetics system is ideally suited to studying this reaction, as we are able to scan both temperature and pressure while maintaining wall‐less conditions, eliminating the possible complications of heterogeneous chemistry. Here we report a temperature‐ and pressure‐dependent study (220–300 K, 50–150 torr) of this reaction; the measured rate constants are in excellent agreement with previously published values down to 240 K, but lie 10–20% lower than the historical data available below that temperature. An analysis of all available data motivates a large (∼ 20%) downward revision in the recommended rate constant below room temperature.