What are Alkynes?

Alkynes are unsaturated hydrocarbons that contain at least one triple bond between carbon atoms. The same prefixes as for alkanes are used according to the number of carbon atoms, but the ending "-ane" is changed to "-yne".

Rules for naming alkynes

To name alkynes correctly, follow these rules:

1. Identify the main chain, which must contain the triple bond (even if it is not the longest).
2. Number the chain so that the triple bond gets the lowest possible locant.
3. Indicate the position of the triple bond with a number before the name of the alkyne.
4. Identify and name the branches (alkyl radicals).
5. List the branches alphabetically (ignoring di-, tri-, etc. prefixes).

Examples of alkynes

1-butyne:

A butyne with the triple bond at position 1.

2-pentyne:

Main chain: pentyne. The triple bond is between carbons 2 and 3.

3-methyl-1-butyne:

A butyne with the triple bond at position 1 and a methyl group at position 3.

4-methyl-2-hexyne:

The main chain is a hexyne with the triple bond at position 2 and a methyl group at position 4. Number from the left to give the lowest position to the triple bond.

penta-1,3-diyne:

The main chain is a diyne with triple bonds at positions 1 and 3. Number from the left to give the lowest positions to the triple bonds.