Phenylacetylene

From Sciencemadness Wiki
Jump to: navigation, search
Phenylacetylene
Phenylacetylene old sample pipette bottle by ChemicalForce.jpg
Old phenylacetylene in a glass pipette
Names
IUPAC name
Ethynylbenzene
Other names
1-Phenylethyne
Phenylacetylide
Phenylethyne
Properties
C8H6
Molar mass 102.133 g/mol
Appearance Colorless or yellow liquid
Density 0.9281 g/cm3 (25 °C)
Melting point −44.8 °C (−48.6 °F; 228.3 K)
Boiling point 143 °C (289 °F; 416 K)
Insoluble
Solubility Miscible with acetone, alcohols, benzene, chloroform, ethers, pyridine, toluene
Vapor pressure 17.6 mm Hg (37.7 °C)
Acidity (pKa) 23.2 (aq, extrapolated)[1]
28.7 (DMSO)[2]
Hazards
Safety data sheet Sigma-Aldrich
Flash point 27 °C (80.6 °F; 300 K)
Related compounds
Related compounds
Acetylene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Phenylacetylene is an alkyne hydrocarbon containing a phenyl group. It exists as a colorless, viscous liquid, though older samples are yellow in color, due to oxidation. In research, it is sometimes used as an analog for acetylene, as being a liquid, it is easier to handle than acetylene gas.

Properties

Chemical

Phenylacetylene burns in air releasing lots of soot.

Phenylacetylene can be reduced by hydrogen over Lindlar catalyst to give styrene.

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

Physical

Phenylacetylene is a colorless liquid, that turns yellow over time if exposed to air.

Availability

Phenylacetylene is sold by chemical suppliers.

Preparation

Phenylacetylene can be prepared by elimination of hydrogen bromide from styrene dibromide using sodium amide in liq. ammonia. Styrene bromide in turn can be made from polystyrene.

KOH or NaOH can also be used instead, while glycerol is used as solvent.[3]

Ethanol can be used instead of glycerol.[4]

Projects

  • Substitute for acetylene in chemical reactions
  • Synthesis of acetophenone
  • Sonogashira coupling
  • Synthesis of rubrene

Handling

Safety

Phenylacetylene is harmful and flammable. Wear proper protection when handling it.

Storage

In closed amber bottles, away from light and air. Inert gas, like argon can be used to limit oxidation.

Disposal

Should be burned in an incinerator, best in a strong oxidizing atmosphere.

References

  1. Streitwieser, A.,Jr.; Ruben, D.M.E; J. Am. Chem. Soc. 1971., 93, p. 1794-1795
  2. Bordwell, F.G. Acc. Chem. Res. 1988, 21, p. 456-463
  3. https://www.youtube.com/watch?v=P4FdbhWzvBE
  4. https://illumina-chemie.de/rubren-t3205.html

Relevant Sciencemadness threads