Diacetylene

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Diacetylene
Structural formula
Space-filling model
Identifiers
CAS number 460-12-8 YesY
PubChem 9997
ChemSpider 9603 YesY
ChEBI CHEBI:37820 YesY
Jmol-3D images Image 1
Properties
Molecular formula C4H2
Molar mass 50.06 g mol−1
Appearance Gas
Melting point −10 °C (14 °F; 263 K)
Boiling point 10 °C (50 °F; 283 K)
Hazards
MSDS External MSDS
R-phrases R11 R19
Main hazards Highly flammable
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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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. The trivial name "diacetylene" refers to the two C-C triple bonds and the possible formation from acetylene (see below). It does not mean that diacetylene is the formal dimer of acetylene, what is rather true for Butenyne or Cyclobutadiene.

Occurrence[edit]

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 low temperatures. Diacetylene has also been found on the Moon.[1]

Preparation[edit]

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≡C-TMS

See also[edit]

References[edit]

  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. ; Coll. Vol. 8: 63 

Further reading[edit]

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