Formula C2H4O Pubchem 11199 | Molar mass 44.053 g/mol | |
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Vinyl alcohol
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.
Contents
5 w v pva poly vinyl alcohol polymer slime
Tautomerization of acetaldehyde to vinyl alcohol
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:
H2C=CHOH → H3CC(O)H ΔH298,g = −42.7 kJ/molThis 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.
Relationship to polyvinylalcohol
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):
n CH2=CHOAc → (CH2−CHOAc)n (CH2−CHOAc)n + n H2O → (CH2−CHOH)n + n HOAcAs a ligand
Several metal complexes are known that contain vinyl alcohol as a ligand. One example is Pt(acac)(η2-C2H3OH)Cl.
Occurrence in interstellar medium
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.