Phenylacetylene

Phenylacetylene
Names
	Preferred IUPAC name Ethynylbenzene
Identifiers
CAS Number	536-74-3 ;
3D model (JSmol)	Interactive image;
ChEMBL	ChEMBL234833 ;
ChemSpider	10364 ;
ECHA InfoCard	100.007.861
PubChem CID	10821;
UNII	239WSR2IBO ;
CompTox Dashboard (EPA)	DTXSID1060211 ;
	InChI InChI=1S/C8H6/c1-2-8-6-4-3-5-7-8/h1,3-7H Key: UEXCJVNBTNXOEH-UHFFFAOYSA-N ; InChI=1/C8H6/c1-2-8-6-4-3-5-7-8/h1,3-7H Key: UEXCJVNBTNXOEH-UHFFFAOYAC;
	SMILES C#Cc1ccccc1;
Properties
Chemical formula	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)	28.7 (DMSO), ; 23.2 (aq, extrapolated)
Magnetic susceptibility (χ)	-72.01·10−6 cm3/mol
	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[]

In the laboratory, phenylacetylene can be prepared by elimination of hydrogen bromide from styrene dibromide using sodium amide in ammonia:^[3]

It can also be prepared by the elimination of hydrogen bromide from bromostyrene using molten potassium hydroxide.^[4]

Reactions[]

Phenylacetylene can be reduced (hydrogenated) by hydrogen over Lindlar catalyst to give styrene.
It undergoes a metal catalyzed trimerization to give 1,2,4- (97%) and 1,3,5-triphenylbenzene:^[5]

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:^[6]

It undergoes a hydration reaction, catalyzed by gold(III) or mercury(II), to give acetophenone.

References[]

^ Bordwell, F.G. Acc. Chem. Res. 1988, 21, 456-463.
^ Streitwieser, A.,Jr.; Ruben, D.M.E; J. Am. Chem. Soc. 1971., 93, 1794-1795.
^ Kenneth N. Campbell, Barbara K. Campbell (1950). "Phenylacetylene". Organic Syntheses. 30: 72. doi:10.15227/orgsyn.030.0072.
^ John C. Hessler (1922). "Phenylacetylene". Organic Syntheses. 2: 67. doi:10.15227/orgsyn.002.0067.
^ 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.
^ 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". . 204–205: 333–340. doi:10.1016/S1381-1169(03)00315-7.

[1] Bordwell, F.G. Acc. Chem. Res. 1988, 21, 456-463.

[2] Streitwieser, A.,Jr.; Ruben, D.M.E; J. Am. Chem. Soc. 1971., 93, 1794-1795.

[3] Kenneth N. Campbell, Barbara K. Campbell (1950). "Phenylacetylene". Organic Syntheses. 30: 72. doi:10.15227/orgsyn.030.0072.

[4] John C. Hessler (1922). "Phenylacetylene". Organic Syntheses. 2: 67. doi:10.15227/orgsyn.002.0067.

[5] 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.

[6] 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". . 204–205: 333–340. doi:10.1016/S1381-1169(03)00315-7.

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Phenylacetylene

Contents

Preparation[]

Reactions[]

See also[]

References[]