Diacetylene (also known as butadiyne) is the

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...

with the formula C₄H₂. It is the simplest compound containing two

triple bond A triple bond in chemistry is a chemical bond between two atoms involving six bonding electrons instead of the usual two in a covalent single bond. Triple bonds are stronger than the equivalent single bonds or double bonds, with a bond order o ...

s. It is first in the series of polyynes, which are of theoretical but not of practical interest.

Occurrence

Diacetylene has been identified in the atmosphere of Titan and in the protoplanetary nebula CRL 618 by its characteristic vibrational spectrum. It is proposed to arise by a reaction between

acetylene Acetylene (systematic name: ethyne) is the chemical compound with the formula and structure . It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in its pure ...

and the

ethynyl radical The ethynyl radical (systematically named λ3-ethyne and hydridodicarbon(''C''—''C'')) is an organic compound with the chemical formula C≡CH (also written CHor ). It is a simple molecule that does not occur naturally on Earth but is abundant ...

(C₂H), which is produced when acetylene undergoes

photolysis Photodissociation, photolysis, photodecomposition, or photofragmentation is a chemical reaction in which molecules of a chemical compound are broken down by photons. It is defined as the interaction of one or more photons with one target molecule. ...

. This radical can in turn attack the triple bond in acetylene and react efficiently even at low temperatures. Diacetylene has also been detected on the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

Preparation

This compound may be made by the

dehydrohalogenation In chemistry, dehydrohalogenation is an elimination reaction which removes a hydrogen halide from a substrate. The reaction is usually associated with the synthesis of alkenes, but it has wider applications. Dehydrohalogenation from alkyl halid ...

of 1,4-dichloro-2-butyne by

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which exp ...

(in alcoholic medium) at ~70°C: : ClCH2C#CCH2Cl + 2 KOH -> HC#C-C#CH + 2 KCl + 2 H2O The bis(

trimethylsilyl A trimethylsilyl group (abbreviated TMS) is a functional group in organic chemistry. This group consists of three methyl groups bonded to a silicon atom minus;Si(CH3)3 which is in turn bonded to the rest of a molecule. This structural group is ch ...

)-protected derivative may be prepared by the Hay coupling of (trimethylsilyl)acetylene: :2 Me3Si-C#CH -> Me3Si-C#C-C#C-SiMe3

Occurrence

Preparation

See also

References

Further reading