Measurements of the kinetics of the OH‐initiated oxidation of isoprene
Measurements of the kinetics of the OH‐initiated oxidation of isoprene
复制标题
OH引发的异戊二烯氧化动力学的测量
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
P. Stevens
中科院分区：
文献类型：
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作者：
B. Chuong;P. Stevens
[1] 在 300 K、100 和 150 Torr 总压下，使用湍流技术结合激光诱导荧光检测 OH 自由基，研究了 OH 引发的异戊二烯氧化机制。在 150 Torr 总压力下，OH 与异戊二烯的反应速率常数测量为 (10.8 ± 0.5) × 10−11 cm3 molecular−1 s−1，且与 100 至 150 Torr 之间的压力无关，与大多数先前的绝对测量值非常一致。在 O2 和 NO 存在的情况下，在 150 Torr 总压下测量了 OH 自由基的传播和由于有机硝酸盐形成而导致的自由基终止导致 OH 的损失，并与该反应系统的动力学模拟进行了比较。这些实验的结果与 NO 与异戊二烯基羟烷基过氧自由基反应的总速率常数 (1.1 ± 0.8) × 10−11 cm3 molecular−1 s−1 一致，双分子通道（NO 氧化为 NO2）的支化比为 0.85 ± 0.10，三分子通道（形成有机物）的支化比为 0.15 ± 0.10。硝酸盐）。尽管这里报告的有机硝酸盐产率是间接测量的结果，但它表明异戊二烯可能是比之前估计的更重要的氮氧化物汇。
[1] The mechanism of the OH-initiated oxidation of isoprene has been studied at 300 K and 100 and 150 Torr total pressure using a turbulent flow technique coupled with laser-induced fluorescence detection of the OH radical. The rate constant for the reaction of OH with isoprene was measured to be (10.8 ± 0.5) × 10−11 cm3 molecule−1 s−1 at 150 Torr total pressure and independent of pressure between 100 and 150 Torr, in excellent agreement with most previous absolute measurements. In the presence of O2 and NO, propagation of OH radicals and loss of OH through radical termination resulting from the formation of organic nitrates were measured at 150 Torr total pressure and compared to simulations of the kinetics of this reaction system. The results of these experiments are consistent with an overall rate constant of (1.1 ± 0.8) × 10−11 cm3 molecule−1 s−1 for the reaction of NO with isoprene-based hydroxyalkyl peroxy radicals, with branching ratios of 0.85 ± 0.10 for the bimolecular channel (oxidation of NO to NO2) and 0.15 ± 0.10 for the termolecular channel (formation of organic nitrates). Although the organic nitrate yield reported here is the result of indirect measurements, it suggests that isoprene may be a more significant sink of NOx than previously estimated.