December 2010

Vinyl Alcohol


Vinyl alcohol (CH2CHOH) was discovered in 2001 in Sgr B2(N) by Turner & Apponi using the 12 m telescope at Kitt Peak National Observatory. The report notes that lines for both the anti and syn conformations of vinyl alcohol were observed. The detection has evidently not been confirmed to date by subsequent observations.

Vinyl alcohol (or ethenol) is the least stable of the three C2H4O isomers, which also include the known astromolecules acetaldehyde and ethylene oxide. While vinyl alcohol can rearrange (tautomerize) into acetaldehyde, too much energy is required for this to occur in the gas phase at low temperature, so vinyl alcohol has a long lifetime in the ISM once it is formed. A number of studies have proposed plausible formation pathways:
 
  • 2003: Hudson & Moore found that vinyl alcohol could be formed through either proton or ultraviolet irradiation of ices composed of water and acetylene.
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  • 2005: Bennett et al. reported that all three C2H4O isomers are formed if carbon dioxide/ethylene ice is irradiated with high energy electrons; vinyl alcohol forms by insertion of hot O atom into one of the CH bonds of ethylene.
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  • 2008: Wang et al. generated vinyl alcohol in cold plasma discharges of various small saturated alcohols such as ethanol.

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