Diacetylene

Diacetylene
Other names 1,3-butadiyne, buta-1,3-diyne, biacetylene, butadiyne
Identifiers
CAS number	460-12-8 Y
PubChem	9997
ChemSpider	9603 Y
ChEBI	CHEBI:37820 Y
Jmol-3D images	Image 1
SMILES C#CC#C
InChI InChI=1S/C4H2/c1-3-4-2/h1-2H Y Key: LLCSWKVOHICRDD-UHFFFAOYSA-N Y InChI=1/C4H2/c1-3-4-2/h1-2H Key: LLCSWKVOHICRDD-UHFFFAOYAU
Properties
Molecular formula	C4H2
Molar mass	50.06 g mol−1
Appearance	Gas
Melting point	-10 °C, 263 K, 14 °F
Boiling point	10 °C, 283 K, 50 °F
Hazards
MSDS	External MSDS
R-phrases	R11 R19
Main hazards	Highly flammable
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Diacetylene (also known as butadiyne), with the formula C₄H₂, is a highly unsaturated hydrocarbon that contains three single bonds and two triple bonds. It is the first in the series of polyynes.

Occurrence

Diacetylene has been identified in the atmosphere of Titan and in the protoplanetary nebula CRL 618 by its characteristic vibrational modes. The molecule is most likely to have formed in Titan's atmosphere 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 cold temperatures. Diacetylene has also been found on the Moon.^[1]

Preparation

This compound may be made by the dehydrohalogenation of 1,4-dichloro-2-butyne by potassium hydroxide at low temperature:^[2]

ClCH₂C≡CCH₂Cl → HC≡C-C≡CH

The bis(trimethylsilyl)-protected derivative may be prepared by the Hay coupling of (trimethylsilyl)acetylene:^[3]

2 (tms)C≡CH → (tms)C≡C-C≡CH

See also

• Acetylene
• Hydrocarbon

References

1. ^ "The Multiplying Mystery of Moonwater", March 18, 2010. Retrieved on 2010-03-18.
2. ^ Verkruijsse, H. D.; Brandsma, L. (1991). "A Detailed procedure for the preparation of Butadiyne". Synthetic Communications 21 (5): 657. doi:10.1080/00397919108020833. 
3. ^ Graham E. Jones, David A. Kendrick, and Andrew B. Holmes (1993), "1,4-Bis(trimethylsilyl)buta-1,3-diyne", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv8p0063 ; Coll. Vol. 8: 63 

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.