イソプレンのガス相光酸化における予期せぬエポキシド形成
Fabien Paulot1, John D Crounse, Henrik G Kjaergaard
1Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125, USA. paulot@caltech.edu
Science (New York, N.Y.)
|August 8, 2009
まとめ
重要な炭化水素であるイソプレンのバイオスフィアの排出は,酸化され,ヒドロキシヒドロペロキシドとジヒドロキシエポキシドを形成します. この発見はイソプレンとイソプレンを結びつける.
科学分野:
- 大気化学 大気化学
- バイオジオケミカルサイクル
- オーガニック・エアロゾール・フォーメーション
背景:
- 非メタン炭化水素のバイオスフィアの排出量は,人為的な源を上回っている.
- イソプレンは,生物学的炭化水素排出量の40%以上を占めています.
- アイソプレンの大気中の酸化は,ヒドロキシルラジカル (OH) によって行われる重要なプロセスです.
研究 の 目的:
- 原始的な大気条件下でのイソプレンの主要酸化産物の解明.
- イソプレン由来中間物質の後の酸化経路を調査する.
- 主要な酸化産物の大気流量とそのエアロゾール形成における役割を定量化するために.
主な方法:
- 制御された条件下での化学酸化実験.
- ヒドロキシヒドロペロキシドおよびディヒドロキシエポキシドを含む反応製品の分析.
- エポキシドの流れをシミュレートするための地球大気モデリング.
主要な成果:
- イソプレンの酸化は主にヒドロキシヒドロペロキシドを生成する.
- さらにOHの酸化により,ダイヒドロキシエポキシドを効率的に生成し,OHをリフォームします.
- グローバルなシミュレーションは,年間約100TgCのエポキシドの流れを示しています.
結論:
- ヒドロキシヒドロペロキシドおよびディヒドロキシエポキシドは,イソプレンの大気分解の主要産物である.
- これらの溶解性が高いエポキシドは,ガス相イソプレン化学と有機エアロゾール形成の間の重要なリンクを代表しています.
- この発見は,バイオジェニックの揮発性有機化合物が空気質と気候に及ぼす影響の仕組み的な理解を提供します.
関連する概念動画
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