Vinyl alcohol

Vinyl alcohol

Names
IUPAC name Ethenol
Other names Hydroxyethene Hydroxyethylene
Identifiers
CAS Number	557-75-5 Y
3D model (Jmol)	Interactive image
ChEMBL	ChEMBL76101 Y
ChemSpider	10726 Y
ECHA InfoCard	100.008.350
PubChem	11199
InChI InChI=1S/C2H4O/c1-2-3/h2-3H,1H2 Y Key: IMROMDMJAWUWLK-UHFFFAOYSA-N Y InChI=1S/C2H4O/c1-2-3/h2-3H,1H2 InChI=1S/C2H4O/c1-2-3/h2-3H,1H2 Key: IMROMDMJAWUWLK-UHFFFAOYSA-N
SMILES OC=C
Properties
Chemical formula	C2H4O
Molar mass	44.053 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Vinyl alcohol, also called ethenol (IUPAC name), is an alcohol. It is not to be confused with the drinking alcohol, ethanol. With the formula CH₂CHOH, vinyl alcohol is an isomer of acetaldehyde and ethylene oxide. It can be formed by elimination of water from ethylene glycol at a temperature of 900 °C and low pressure.

Under normal conditions, vinyl alcohol converts (tautomerizes) to acetaldehyde:

At room temperature, acetaldehyde (H₃CC(O)H) is more stable than vinyl alcohol (H₂C=CHOH) by 42.7 kJ/mol:

This keto-enol tautomerization has a high barrier and does therefore not occur near room temperature. This tautomerization can be catalyzed via photochemical process. These findings suggest that the keto-enol tautomerization is a viable route under atmospheric and stratospheric conditions, relevant to a role for vinyl alcohol in the production of organic acids in the atmosphere.

Because of the instability of vinyl alcohol, the thermoplastic polyvinyl alcohol (PVA or PVOH) is made indirectly by polymerization of vinyl acetate followed by hydrolysis of the ester bonds (Ac = acetyl, HOAc = acetic acid):

Several metal complexes are known that contain vinyl alcohol as a ligand. One example is Pt(acac)(η²-C₂H₃OH)Cl.

Vinyl alcohol was discovered in the molecular cloud Sagittarius B using the 12-meter radio telescope at the Kitt Peak National Observatory. This vinyl alcohol being stable in the (dilute) interstellar medium shows that its tautomerization is not unimolecular.