Atmospheric oxidation mechanism of naphthalene initiated by OH radical. A theoretical study.
Atmospheric oxidation mechanism of naphthalene initiated by OH radical. A theoretical study.
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DOI：
10.1039/c2cp23271e
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发表时间：
2012-02
期刊：
影响因子：
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通讯作者：
Zhijie Zhang;Ling Lin;Liming Wang
中科院分区：
文献类型：
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作者：
Zhijie Zhang;Ling Lin;Liming Wang
用密度泛函理论在B3LYP和BB1K水平上研究了羟基引发的萘(NAP)大气氧化反应机理。起始步骤主要是Nap的C(1)位上的OH加成生成自由基C(10)H(8)-1-OH(R1)，然后是C(2)上的O(2)加成生成过氧基R1-2OO，或被O(2)抽氢生成1-萘酚。在大气中，r1-2OO会与NO反应生成r1-2O，发生分子内氢从-OH到-OO的转移，形成r1-P2O1自由基，或者可能对r1-29OO双环自由基进行封环反应；而其他双环中间基的形成是可以忽略的，因为>；100kJmo1(-1)(相对于r1+O(2))具有极高的Gibbs能垒。该反应机理不同于苯的氧化机理，其中双环中间体起着重要作用。自由基R1-P2O1将解离为2-甲酰肉桂醛，而R1-2O将通过类环氧化物中间体转化为稳定的产物C(10)H(6)O(3)。在以前的实验研究中提出的一些反应路径被发现是无效的。
The atmospheric oxidation mechanism of naphthalene (Nap) initiated by the OH radical is investigated using density functional theory at B3LYP and BB1K levels. The initial step is dominated by OH addition to the C(1)-position of Nap, forming radical C(10)H(8)-1-OH (R1), followed by the O(2) additions to the C(2) position to form peroxy radical R1-2OO, or by the hydrogen abstraction by O(2) to form 1-naphthol. In the atmosphere, R1-2OO will react with NO to form R1-2O, undergo intramolecular hydrogen transfer from -OH to -OO to form R1-P2O1 radicals, or possibly undergo ring-closure to R1-29OO bi-cyclic radical; while the formation of other bi-cyclic intermediate radicals is negligible because of the extremely high Gibbs energy barriers of >100 kJ mol(-1) (relative to R1+O(2)). The mechanism is different from the oxidation mechanism of benzene, where the bi-cyclic intermediates play an important role. Radicals R1-P2O1 will dissociate to 2-formylcinnamaldehyde, while R1-2O will be transformed to stable products C(10)H(6)O(3) via epoxide-like intermediates. A few reaction pathways suggested in previous experimental studies are found to be invalid.