2026-08-25 カリフォルニア大学リバーサイド校(UCR)
＜関連情報＞
- https://news.ucr.edu/articles/2026/08/25/study-finally-captures-how-smog-begins
- https://www.nature.com/articles/s41467-026-73307-6
- https://www.nature.com/articles/s41467-025-61739-5
イソプレンオゾン分解におけるクリーギー中間体の直接測定 Direct measurement of Criegee intermediates in isoprene ozonolysis
Lei Yang,Katia Hatem,Mixtli Campos-Pineda & Jingsong Zhang
Nature Communications Published:20 May 2026
DOI:https://doi.org/10.1038/s41467-026-73307-6
Abstract
Isoprene is the most abundant unsaturated hydrocarbon in the troposphere. Carbonyl oxides, also called Criegee intermediates, are highly reactive transient species in the ozonolysis of alkenes that play important roles in tropospheric oxidation. Despite decades of efforts, direct observation of Criegee intermediates in isoprene ozonolysis has not been achieved. Here we show the first direct measurement of Criegee intermediates produced in isoprene ozonolysis. Ultra-violet spectra of Criegee intermediates are captured with cavity ringdown spectroscopy and match oscillatory π* ← π transitions of CH2OO. The in-situ concentration time profiles of Criegee intermediates allow direct kinetic studies and benchmark the isoprene ozonolysis reaction network. The results indicate that CH2OO dominates stabilized Criegee intermediate chemistry in the low-pressure region, while the role of larger stabilized four-carbon Criegee intermediates could be important in tropospheric oxidation.
エテンのオゾン分解におけるクリーギー中間体CH₂OOの直接測定 Direct measurement of the Criegee intermediate CH2OO in ozonolysis of ethene
Mixtli Campos-Pineda,Lei Yang & Jingsong Zhang
Nature Communications Published:15 July 2025
DOI:https://doi.org/10.1038/s41467-025-61739-5
Abstract
The transient species produced from reactions of unsaturated hydrocarbons with ozone, carbonyl oxides, termed “Criegee intermediates”, play a key role in tropospheric oxidation mechanisms. Direct observation and characterization of Criegee intermediates in ozonolysis in situ were proven difficult in decades of efforts. Here, we report the direct measurement of the simplest Criegee intermediate, CH2OO, from ozonolysis of ethene by cavity ring-down spectroscopy in a flow cell reactor. The transient CH2OO is quantified rapidly by near-ultraviolet absorption spectra via its B̃(1A′) ← X̃(1A′) transition. Time profiles of CH2OO produced in ozonolysis under quasi-steady state conditions are observed. These CH2OO concentration profiles benchmark the modeling of the ethene ozonolysis reaction network and mechanism, allowing for determination of the yield and various kinetic data of CH2OO.
