Phenylacetylene

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Phenylacetylene
Phenylacetylene
Phenylacetylene-3D-balls.png
Names
IUPAC name
Ethynylbenzene
Identifiers
536-74-3 YesY
ChEMBL ChEMBL234833 YesY
ChemSpider 10364 YesY
Jmol 3D model Interactive image
PubChem 10821
Properties
C8H6
Molar mass 102.133 g/mol
Density 0.93 g/cm3
Melting point −45 °C (−49 °F; 228 K)
Boiling point 142 to 144 °C (288 to 291 °F; 415 to 417 K)
Acidity (pKa) 28.8
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Phenylacetylene is an alkyne hydrocarbon containing a phenyl group. It exists as a colorless, viscous liquid. In research, it is sometimes used as an analog for acetylene; being a liquid, it is easier to handle than acetylene gas.

Preparation[edit]

In the laboratory, phenylacetylene can be prepared by elimination of hydrogen bromide from styrene dibromide using sodium amide in ammonia:[1]

Phenylacetylene prepn.png

It can also be prepared by the elimination of hydrogen bromide from bromostyrene using molten potassium hydroxide.[2]

Reactions[edit]

PhCCH trimerisation.svg
  • Choosing a rhodium catalyst leads to the cyclotrimerization producing both the 1,2,4- and 1,3,5- isomers along with substantial quantities of acyclic enyne dimer products:[4]
Cyclotri limits.png
AlkyneHydrolysis.svg

See also[edit]

References[edit]

  1. ^ Kenneth N. Campbell and Barbara K. Campbell (1963). "Phenylacetylene". Org. Synth. ; Coll. Vol. 4, p. 763 
  2. ^ John C. Hessler (1941). "Phenylacetylene". Org. Synth. ; Coll. Vol. 1, p. 438 
  3. ^ Gerhard Hilt; Thomas Vogler; Wilfried Hess; Fabrizio Galbiati (2005). "A simple cobalt catalyst system for the efficient and regioselective cyclotrimerisation of alkynes". Chemical Communications 2005 (11): 1474–1475. doi:10.1039/b417832g. PMID 15756340. 
  4. ^ Ardizzoia, G. A.; Brenna, S.; Cenini, S.; LaMonica, G.; Masciocchi, N.; Maspero, A. (2003). "Oligomerization and Polymerization of Alkynes Catalyzed by Rhodium(I) Pyrazolate Complexes". Journal of Molecular Catalysis A: Chemical. 204–205: 333–340. doi:10.1016/S1381-1169(03)00315-7.