酸化反応で長年存在が予測されていた分子を初めて直接観測 (Scientists confirm existence of molecule long believed to occur in oxidation)

2026-03-13 スウェーデン王立工科大学（KTH）

＜関連情報＞

• https://www.kth.se/en/om/nyheter/centrala-nyheter/scientists-confirm-existence-of-molecule-long-believed-to-occur-in-oxidation-1.1462925
• https://www.science.org/doi/10.1126/sciadv.aeb6495

気相ラジカル反応における捉えどころのない四酸化物の観測は、ラッセル機構を支持する Observing elusive tetroxides in gas-phase radical reactions supports the Russell mechanism

Barbara Nozière and Roger Patrick
Science Advances  Published:13 Mar 2026

Abstract

Organic peroxy radicals (RO₂) are important intermediates for oxidation processes in aerobic chemical systems. Their self- and “cross”-reactions (i.e., with themselves and other RO₂) are increasingly receiving attention in a wide range of applications, from atmospheric chemistry to cancer therapies. However, their mechanism has been debated for decades. The Russell mechanism, widely assumed for these reactions today, is characterized by a tetroxide intermediate, only observed once and partially since its postulate in 1957. Here we report the observation of tetroxides in the gas-phase reactions of different RO₂ by direct mass spectrometry, in which ionic and gas-phase dimerization could be ruled out. Within the uncertainties in the kinetic profiles, the lifetime for CH₃OOOOCH₃ was determined to be in the range 0.2 and 200 milliseconds, consistent with an intermediate and supporting the Russell mechanism.