-In organic chemistry, an alkyne is an unsaturated hydrocarbon. Alkynes are organic molecules made of the functional group carbon-carbon triple bonds. They are written in the empirical formula of CnH2n-2.

 

*Chemical Properties

 

-Alkynes are more unsaturated than alkenes. Thus they add two equivalents of bromine whereas an alkene adds only one equivalent. In some reactions, alkynes are less reactive than alkenes. Possible explanations involve the two π-bonds in the alkyne delocalizing, which would reduce the energy of the π-system or the stability of the intermediates during the reaction. They show greater tendency to polymerize than alkenes do. 

 

*Naming Simple Alkynes

 

-Alkanes are named by adding the the -yne suffix to the prefix associated with the number of carbon atoms present in the molecule. A number and dash before the name denotes the number of the carbon atom in the chain that begins the triple bond.

 

*Examples:

 

Ethyne

Number of Carbons: 2
Prefix: eth- Number of Hydrogens: 2(2)-2 = 4-2 = 2
Molecular Formula: C2H2

 

 

 

 

 

 

Propyne

Number of Carbon Atoms: 3

Prefix: prop- Number of Hydrogens: 2(3)-2 = 6-2 = 4

Molecular Formula: C3H4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

*Activity: Name the following alkynes.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

*Answer key:

A. Pentyne

B. Hexyne

C. Octyne

D. Nonyne

E. Decyne

 

 

 

 

 

Reference:

          http://chemwiki.ucdavis.edu/Organic_Chemistry/Hydrocarbons/Alkynes

 

 

 

Written by: Ian Paulo Parungao