Formation of All Three C2H4O Isomers—Ethylene Oxide (c-C2H4O), Acetaldehyde (CH3CHO), and Vinyl Alcohol (CH2CHOH)—in Ethanol-containing Interstellar Analog Ices
Oxygen-containing complex organic molecules are key precursors to biorelevant compounds fundamental for the origins of life. However, the untangling of their interstellar formation mechanisms has just scratched the surface, especially for oxygen-containing cyclic molecules. Here, we present the firs...
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2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4357/adc308 |
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| author | Jia Wang Chaojiang Zhang Joshua H. Marks Ralf I. Kaiser |
| author_facet | Jia Wang Chaojiang Zhang Joshua H. Marks Ralf I. Kaiser |
| author_sort | Jia Wang |
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| description | Oxygen-containing complex organic molecules are key precursors to biorelevant compounds fundamental for the origins of life. However, the untangling of their interstellar formation mechanisms has just scratched the surface, especially for oxygen-containing cyclic molecules. Here, we present the first laboratory simulation experiments featuring the formation of all three C _2 H _4 O isomers—ethylene oxide ( c –C _2 H _4 O), acetaldehyde (CH _3 CHO), and vinyl alcohol (CH _2 CHOH)—in low-temperature model interstellar ices composed of carbon monoxide (CO) and ethanol (C _2 H _5 OH). Ice mixtures were exposed to galactic cosmic-ray proxies with an irradiation dose equivalent to a cold molecular cloud aged (7 ± 2) × 10 ^5 yr. These biorelevant species were detected in the gas phase through isomer-selective photoionization reflectron time-of-flight mass spectrometry during temperature-programmed desorption. Isotopic labeling experiments reveal that ethylene oxide is produced from ethanol alone, providing the first experimental evidence to support the hypothesis that ethanol serves as a precursor to the prototype epoxide in interstellar ices. These findings reveal feasible pathways for the formation of all three C _2 H _4 O isomers in ethanol-rich interstellar ices, offering valuable constraints on astrochemical models for their formation. Our results suggest that ethanol is a critical precursor to C _2 H _4 O isomers in interstellar environments, representing a critical step toward unraveling the formation mechanisms of oxygen-containing cyclic molecules, aldehydes, and their enol tautomers from alcohols in interstellar ices. |
| format | Article |
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| institution | DOAJ |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
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| spelling | doaj-art-fe7567480abb4dfa8b4cbe9c44f480c12025-08-20T03:11:32ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01984213810.3847/1538-4357/adc308Formation of All Three C2H4O Isomers—Ethylene Oxide (c-C2H4O), Acetaldehyde (CH3CHO), and Vinyl Alcohol (CH2CHOH)—in Ethanol-containing Interstellar Analog IcesJia Wang0https://orcid.org/0000-0002-3795-8699Chaojiang Zhang1https://orcid.org/0000-0003-3727-901XJoshua H. Marks2https://orcid.org/0000-0003-0492-2494Ralf I. Kaiser3https://orcid.org/0000-0002-7233-7206W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa , Honolulu, HI 96822, USA ; ralfk@hawaii.edu; Department of Chemistry, University of Hawaii at Manoa , Honolulu, HI 96822, USAW. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa , Honolulu, HI 96822, USA ; ralfk@hawaii.edu; Department of Chemistry, University of Hawaii at Manoa , Honolulu, HI 96822, USAW. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa , Honolulu, HI 96822, USA ; ralfk@hawaii.edu; Department of Chemistry, University of Hawaii at Manoa , Honolulu, HI 96822, USAW. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa , Honolulu, HI 96822, USA ; ralfk@hawaii.edu; Department of Chemistry, University of Hawaii at Manoa , Honolulu, HI 96822, USAOxygen-containing complex organic molecules are key precursors to biorelevant compounds fundamental for the origins of life. However, the untangling of their interstellar formation mechanisms has just scratched the surface, especially for oxygen-containing cyclic molecules. Here, we present the first laboratory simulation experiments featuring the formation of all three C _2 H _4 O isomers—ethylene oxide ( c –C _2 H _4 O), acetaldehyde (CH _3 CHO), and vinyl alcohol (CH _2 CHOH)—in low-temperature model interstellar ices composed of carbon monoxide (CO) and ethanol (C _2 H _5 OH). Ice mixtures were exposed to galactic cosmic-ray proxies with an irradiation dose equivalent to a cold molecular cloud aged (7 ± 2) × 10 ^5 yr. These biorelevant species were detected in the gas phase through isomer-selective photoionization reflectron time-of-flight mass spectrometry during temperature-programmed desorption. Isotopic labeling experiments reveal that ethylene oxide is produced from ethanol alone, providing the first experimental evidence to support the hypothesis that ethanol serves as a precursor to the prototype epoxide in interstellar ices. These findings reveal feasible pathways for the formation of all three C _2 H _4 O isomers in ethanol-rich interstellar ices, offering valuable constraints on astrochemical models for their formation. Our results suggest that ethanol is a critical precursor to C _2 H _4 O isomers in interstellar environments, representing a critical step toward unraveling the formation mechanisms of oxygen-containing cyclic molecules, aldehydes, and their enol tautomers from alcohols in interstellar ices.https://doi.org/10.3847/1538-4357/adc308Laboratory astrophysicsAstrochemistryMass spectrometryComplex organic moleculesInterstellar molecules |
| spellingShingle | Jia Wang Chaojiang Zhang Joshua H. Marks Ralf I. Kaiser Formation of All Three C2H4O Isomers—Ethylene Oxide (c-C2H4O), Acetaldehyde (CH3CHO), and Vinyl Alcohol (CH2CHOH)—in Ethanol-containing Interstellar Analog Ices The Astrophysical Journal Laboratory astrophysics Astrochemistry Mass spectrometry Complex organic molecules Interstellar molecules |
| title | Formation of All Three C2H4O Isomers—Ethylene Oxide (c-C2H4O), Acetaldehyde (CH3CHO), and Vinyl Alcohol (CH2CHOH)—in Ethanol-containing Interstellar Analog Ices |
| title_full | Formation of All Three C2H4O Isomers—Ethylene Oxide (c-C2H4O), Acetaldehyde (CH3CHO), and Vinyl Alcohol (CH2CHOH)—in Ethanol-containing Interstellar Analog Ices |
| title_fullStr | Formation of All Three C2H4O Isomers—Ethylene Oxide (c-C2H4O), Acetaldehyde (CH3CHO), and Vinyl Alcohol (CH2CHOH)—in Ethanol-containing Interstellar Analog Ices |
| title_full_unstemmed | Formation of All Three C2H4O Isomers—Ethylene Oxide (c-C2H4O), Acetaldehyde (CH3CHO), and Vinyl Alcohol (CH2CHOH)—in Ethanol-containing Interstellar Analog Ices |
| title_short | Formation of All Three C2H4O Isomers—Ethylene Oxide (c-C2H4O), Acetaldehyde (CH3CHO), and Vinyl Alcohol (CH2CHOH)—in Ethanol-containing Interstellar Analog Ices |
| title_sort | formation of all three c2h4o isomers ethylene oxide c c2h4o acetaldehyde ch3cho and vinyl alcohol ch2choh in ethanol containing interstellar analog ices |
| topic | Laboratory astrophysics Astrochemistry Mass spectrometry Complex organic molecules Interstellar molecules |
| url | https://doi.org/10.3847/1538-4357/adc308 |
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