トロポパウスの化学を再考: HO2*が誘発した酸化が効率的なアセトンシンクとして利用される
Ive Hermans1, Thanh L Nguyen, Pierre A Jacobs
1Department of Chemistry, Celestijnenlaan 200F, B-3001 Heverlee, Belgium.
Journal of the American Chemical Society
|August 12, 2004
まとめ
アセトンはHO2ラジカルと反応し,新しい化合物を形成します. この反応は,トロポパウズ近くで顕著になり,酸エステンの豊富さを説明し,アセトンシンクとして作用します.
科学分野:
- 大気化学 大気化学
- トロポスフィアの上部とストラトスフィアの下部 (UTLS) 研究
- 化学動力学 化学動力学
背景:
- アセトンは,上層トロポスフィアと下層ストラトスフィアの化学における重要な分子です.
- アセトンとHO2基間の反応は,以前見過ごされていた.
- 酸は,熱帯圏地域で観察される豊富な有機酸です.
研究 の 目的:
- アセトンがHO2基と反応する過程を研究する.
- UTLSにおけるこの反応の重要性を判断する.
- トロポパウズ付近で観察された酸の豊富さを説明するために.
主な方法:
- 検証された計算方法論を用いた理論的研究.
- 変化する温度条件下における化学均衡の変化の分析.
- アセトン,HO2,およびNOを含む反応経路の運動モデリング.
主要な成果:
- アセトンとHO2ラジカルの反応により, (CH3) 2C=O + HO2* <=> (CH3) 2C(OH) OO*の急速な均衡が形成されます.
- 室温では,均衡は反応物質に好意を示し,反応を無意味にします.
- トロポパウズ (T <= 220 K) の近くでは,均衡が製品にシフトし,アセトンの効率的な除去を可能にします.
- その後の酸化窒素 (NO) との反応により,酸エステンが形成されます.
結論:
- アセトンのHO2ラジカルとの反応は,UTLSにおけるアセトンの除去のための重要な経路である.
- この反応経路は,熱断層の近くで見られた高い濃度の酸エステンを説明する.
- このアセトンシンクメカニズムには,空中交通によって発生するNOが役割を果たします.
関連する概念動画
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In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
02:04Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids
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01:46Oxidative Cleavage of Alkenes: Ozonolysis
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Ozone is a symmetrical bent molecule stabilized by a resonance structure.
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02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
Introduction
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02:37Oxidation of Alcohols
In this lesson, the oxidation of alcohols is discussed in depth. The various reagents used for oxidation of primary and secondary alcohols are detailed, and their mechanism of action is provided.
The process of oxidation in a chemical reaction is observed in any of the three forms:
The process of oxidation in a chemical reaction is observed in any of the three forms:
01:15Oxidations of Aldehydes and Ketones to Carboxylic Acids
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Aldehydes readily undergo oxidation in strong oxidizing agents such as potassium permanganate and chromic acid. The oxidation can also be carried out using mild oxidizing agents such as silver oxide. In fact, aldehydes can be easily oxidized...
Aldehydes readily undergo oxidation in strong oxidizing agents such as potassium permanganate and chromic acid. The oxidation can also be carried out using mild oxidizing agents such as silver oxide. In fact, aldehydes can be easily oxidized...