Observation of the simplest Criegee intermediate CH[subscript 2]OO in the gas-phase ozonolysis of ethylene
Ozonolysis is one of the dominant oxidation pathways for tropospheric alkenes. Although numerous studies have confirmed a 1,3-cycloaddition mechanism that generates a Criegee intermediate (CI) with form R[subscript 1]R[subscript 2]COO, no small CIs have ever been directly observed in the ozonolysis...
| Main Authors: | , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
American Association for the Advancement of Science (AAAS)
2015
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| Online Access: | http://hdl.handle.net/1721.1/96419 https://orcid.org/0000-0002-7609-4205 |
| Summary: | Ozonolysis is one of the dominant oxidation pathways for tropospheric alkenes. Although numerous studies have confirmed a 1,3-cycloaddition mechanism that generates a Criegee intermediate (CI) with form R[subscript 1]R[subscript 2]COO, no small CIs have ever been directly observed in the ozonolysis of alkenes because of their high reactivity. We present the first experimental detection of CH[subscript 2]OO in the gas-phase ozonolysis of ethylene, using Fourier transform microwave spectroscopy and a modified pulsed nozzle, which combines high reactant concentrations with rapid sampling and sensitive detection. Nine other product species of the O[subscript 3] + C[subscript 2]H[subscript 4] reaction were also detected, including formaldehyde, formic acid, dioxirane, and ethylene ozonide. The presence of all these species can be attributed to the unimolecular and bimolecular reactions of CH[subscript 2]OO, and their abundances are in qualitative agreement with published mechanisms and rate constants. |
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