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Diacetylene

Names
Preferred IUPAC name Buta-1,3-diyne
Other names 1,3-Butadiyne Biacetylene Butadiyne
Identifiers
CAS Number	460-12-8
3D model (JSmol)	Interactive image
Beilstein Reference	1236317
ChEBI	CHEBI:37820
ChemSpider	9603
ECHA InfoCard	100.006.641
EC Number	207-303-9
PubChem CID	9997
UNII	6389J044O5
CompTox Dashboard (EPA)	DTXSID8060036
InChI InChI=1S/C4H2/c1-3-4-2/h1-2HKey: LLCSWKVOHICRDD-UHFFFAOYSA-N InChI=1/C4H2/c1-3-4-2/h1-2HKey: LLCSWKVOHICRDD-UHFFFAOYAU
SMILES C#CC#C
Properties
Chemical formula	C4H2
Molar mass	50.060 g·mol
Appearance	Gas
Boiling point	10 °C (50 °F; 283 K)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Highly flammable; Peroxide forming
GHS labelling:
Pictograms
Signal word	Danger
Safety data sheet (SDS)	External MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Y verify (what is  ?) Infobox references

Diacetylene (also known as butadiyne) is the organic compound with the formula C₄H₂. It is the simplest compound containing two triple bonds. 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 and the ethynyl radical (C₂H), which is produced when acetylene undergoes photolysis. 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.

Preparation

This compound may be made by the dehydrohalogenation of 1,4-dichloro-2-butyne by potassium hydroxide (in alcoholic medium) at ~70°C:

${\displaystyle {\ce {ClCH2C#CCH2Cl + 2 KOH -> HC#C-C#CH + 2 KCl + 2 H2O}}}$

The bis(trimethylsilyl)-protected derivative may be prepared by the Hay coupling of (trimethylsilyl)acetylene:

${\displaystyle {\ce {2 Me3Si-C#CH -> Me3Si-C#C-C#C-SiMe3}}}$

See also

• Acetylene
• Diiodobutadiyne
• Butenyne
• Hydrocarbon

References

1. Verkruijsse, H. D.; Brandsma, L. (1991). "A Detailed Procedure for the Preparation of Butadiyne". Synthetic Communications. 21 (5): 657. doi:10.1080/00397919108020833.
2. Graham E. Jones; David A. Kendrick; Andrew B. Holmes (1987). "1,4-Bis(trimethylsilyl)buta-1,3-diyne". Organic Syntheses. 65: 52. doi:10.15227/orgsyn.065.0052.

Further reading

• Maretina, Irina A; Trofimov, Boris A (2000). "Diacetylene: a candidate for industrially important reactions". Russian Chemical Reviews. 69 (7): 591. doi:10.1070/RC2000v069n07ABEH000564. S2CID 250889660.

v t e Molecules detected in outer space
Molecules	Diatomic Aluminium monochloride Aluminium monofluoride Aluminium(II) oxide Argonium Carbon cation Carbon monophosphide Carbon monosulfide Carbon monoxide Cyano radical Diatomic carbon Fluoromethylidynium Helium hydride ion Hydrogen chloride Hydrogen fluoride Hydrogen (molecular) Hydroxyl radical Iron(II) oxide Magnesium monohydride Methylidyne radical Nitric oxide Nitrogen (molecular) Imidogen Sulfur mononitride Oxygen (molecular) Phosphorus monoxide Phosphorus mononitride Potassium chloride Silicon carbide Silicon monoxide Silicon monosulfide Sodium chloride Sodium iodide Sulfanyl Sulfur monoxide Titanium(II) oxide Triatomic Aluminium(I) hydroxide Aluminium isocyanide Amino radical Carbon dioxide Carbonyl sulfide CCP radical Chloronium Diazenylium Dicarbon monoxide Disilicon carbide Ethynyl radical Formyl radical Hydrogen cyanide (HCN) Hydrogen isocyanide (HNC) Hydrogen sulfide Hydroperoxyl Iron cyanide Isoformyl Magnesium cyanide Magnesium isocyanide Methylene N2H Nitrous oxide Nitroxyl Ozone Methylidynephosphane Potassium cyanide Trihydrogen cation Sodium cyanide Sodium hydroxide Silicon carbonitride c-Silicon dicarbide SiNC Sulfur dioxide Thioformyl Thioxoethenylidene Titanium dioxide Tricarbon Water Four atoms Acetylene Ammonia Isocyanic acid Cyanoethynyl Formaldehyde Fulminic acid HCCN Hydrogen peroxide Hydromagnesium isocyanide Isocyanic acid Isothiocyanic acid Ketenyl Methylene amidogen Methyl cation Methyl radical Propynylidyne Protonated carbon dioxide Protonated hydrogen cyanide Silicon tricarbide Thioformaldehyde Tricarbon monoxide Tricarbon monosulfide Thiocyanic acid Five atoms Ammonium ion Butadiynyl Carbodiimide Cyanamide Cyanoacetylene Cyanoformaldehyde Cyanomethyl Cyclopropenylidene Formic acid Isocyanoacetylene Ketene Methane Methoxy radical Methylenimine Propadienylidene Protonated formaldehyde Silane Silicon-carbide cluster Six atoms Acetonitrile Cyanobutadiynyl radical E-Cyanomethanimine Cyclopropenone Diacetylene Ethylene Formamide HC4N Ketenimine Methanethiol Methanol Methyl isocyanide Pentynylidyne Propynal Protonated cyanoacetylene Seven atoms Acetaldehyde Acrylonitrile Vinyl cyanide Cyanodiacetylene Ethylene oxide Glycolonitrile Hexatriynyl radical Propyne Methylamine Methyl isocyanate Vinyl alcohol Eight atoms Acetic acid Aminoacetonitrile Cyanoallene Ethanimine Glycolaldehyde Hexapentaenylidene Methylcyanoacetylene Methyl formate Acrolein Nine atoms Acetamide Cyanohexatriyne Dimethyl ether Ethanol Methyldiacetylene Octatetraynyl radical Propene Ethanethiol Propionitrile N-Methylformamide Ten atoms or more Acetone Benzene Benzonitrile Buckminsterfullerene (C60, C60, fullerene, buckyball) C70 fullerene Cyanodecapentayne Ethylene glycol Ethyl formate Methyl acetate Methyl-cyano-diacetylene Methyltriacetylene Propionaldehyde Butyronitrile Pyrimidine Heptatrienyl radical
Deuterated molecules	Ammonia Ammonium ion Formaldehyde Formyl radical Heavy water Hydrogen cyanide Hydrogen deuteride Hydrogen isocyanide Propyne N2D Trihydrogen cation
Unconfirmed	Anthracene Dihydroxyacetone Methoxyethane Glycine Graphene Hemolithin H2NCO Linear C5 Naphthalene cation Phosphine Pyrene Silylidyne
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• Conjugated diynes