CRIEGEE INTERMEDIATE CH₂OO IN THE OXIDATION OF ETHANE

Prozument, Kirill

Permalink

https://hdl.handle.net/2142/122332 Copy

Description

Title

CRIEGEE INTERMEDIATE CH₂OO IN THE OXIDATION OF ETHANE

Author(s)

Prozument, Kirill

Contributor(s)

• Sivaramakrishnan, Raghu
• Seifert, Nathan A.

Issue Date

2023-06-20

Keyword(s)

Radicals

Abstract

The family of Criegee intermediates, commonly designated as QOO, where Q is CH₂, CH₃CH, and so on, has been predicted by Rudolf Criegee in 1949 and discovered recently in laboratory studies. These highly unstable and reactive species are important in the atmosphere where they are formed by ozonolysis of alkenes. To investigate its chemistry, CH₂OO has been produced in various laboratory settings by either ozonolysis of CH₂CH₂, photodissociation of CH₂I₂ followed by oxidation, or oxidation of CH₄ under the discharge conditions. At Argonne, we observe CH₂OO resulting from the oxidation of CH₃CH₃ in a continuous-flow SiC microreactor heated to 1700 K. Cold (Trₒt = 7 K) Criegee intermediate is detected in the supersonic molecular beam emerging from the hot microreactor and using the chirped-pulse Fourier transform millimeter-wave spectrometer, which operates in the 60–90 GHz region and is equipped with a fast narrowband digitizer for averaging 10⁷ free induction decay traces in 5 minutes. The branching ratios of CH₂OO to the main oxidation products HO₂ and CH₂O are measured as a function of reactor temperature. We discuss the possible chemical pathways and the thermodynamic conditions within the reactor and outside of it that may lead to the formation and retention of the “fragile” CH₂OO intermediate in this experiment.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Handle URL

https://hdl.handle.net/2142/122332

DOI

https://doi.org/10.15278/isms.2023.6870

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