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Vinylacetylene

Vinylacetylene
Vinylacetylene-2D.png
Vinylacetylene-2D-skeletal.png
Vinylacetylene-3D-vdW.png
Names
Preferred IUPAC name
But-1-en-3-yne
Other names
Butenyne
3-Butene-1-yne
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.010.650
PubChem CID
Properties
C4H4
Molar mass 52.07456 g/mol
Appearance colourless gas
Boiling point 0 to 6 °C (32 to 43 °F; 273 to 279 K)
low
Hazards
Main hazards flammable
NFPA 704
Flammability code 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g., propane Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 3: Capable of detonation or explosive decomposition but requires a strong initiating source, must be heated under confinement before initiation, reacts explosively with water, or will detonate if severely shocked. E.g., fluorine Special hazard W: Reacts with water in an unusual or dangerous manner. E.g., cesium, sodiumNFPA 704 four-colored diamond
Flash point < −5 °C (23 °F; 268 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY  (what is YesYN ?)
Infobox references

Vinylacetylene is the organic compound with the formula C4H4. The colourless gas was once used in the polymer industry. It is composed of both alkyne and alkene groups.

Vinylacetylene is extremely dangerous because in high enough concentrations (typically > 30 mole percent, but pressure dependent) it can auto-detonate (explode without air being present) especially at elevated pressures, such as those seen in chemical plants processing C4 hydrocarbons. An example of such an explosion occurred at a Union Carbide plant in Texas City in 1969.

Vinylacetylene was first synthesized by Hofmann elimination of the related quaternary ammonium salt:

It is usually synthesized by dehydrohalogenation of 1,3-dichloro-2-butene. It also arises via the dimerization of acetylene or dehydrogenation of 1,3-butadiene.

At one time, chloroprene (2-chloro-1,3-butadiene), an industrially important monomer, was produced via the intermediacy of vinyl acetylene. In this process, acetylene is dimerized to give vinyl acetylene, which is then combined with hydrogen chloride to give 4-chloro-1,2-butadiene via 1,4-addition. This allene derivative which, in the presence of cuprous chloride, rearranges to 2-chloro-1,3-butadiene:


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Wikipedia

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