Alkanes IUPAC Naming Examples
Naming a organic compound is a multi step process and should be done very carefully. But naming alkane is the easiest in among them. When naming alkane, that includes selecting longest carbon chain, identifying substituents, numbering carbon chain properly and some other steps. We will discuss those steps and examples to write IUPAC names of alkanes.
Identify longest continuous carbon chain
Identify longest continuous carbon chain (which includes maximum number of carbon atoms). It is called root chain. Then other carbon atoms which not included in root chain are defined as substituents or branched chains. There are five carbon atoms in the root chain and two substituents in the below organic molecule.
Naming substituents in IUPAC naming
Some substituents and their substituent names are noted below.
- -CH3 - methyl
- -CH2CH3 - ethyl
- -CH2CH2CH3 - propyl
- -Br - bromo
- -Cl - chloro
When writing IUPAC name, we first write substituents chain name and then root chain. Don't think about much in this level. You will understand more when examples are discussed.
Alkane IUPAC naming - Example 1
- Select longest carbon chain, root chain which is circled and bold in Fig 2. There are six 6 carbon atoms
in the root chain.
- Determine substituent(s). Substituents are highlighted (black bold) in fig 2.
CH3 - methyl
CH2CH3 - ethyl
Substituent are named according to alphabetical order, Therefore first comes ethyl group and then methyl group and substituent part is named as below.
- Start numbering carbon chain. ethyl group gets lower position because it exists first in the name
according to the alphabetical order of substituents.
- Write the name finish the name as ane due to six carbon atoms in the chain, finish the
name as hexane. Then complete the name