naming alkanes.
Before proceeding on the steps on how to correctly name and identify alkanes, alkanes should be defined first. Alkanes are hydrocarbons which can only form a single bond unlike alkenes and alkynes which can form double and triple bonds respectively. The IUPAC Nomenclature are the guidelines that are needed to be followed in order to name the alkanes. Take note that the first ten alkanes should be memorized because most of them appear in different IUPAC names. The IUPAC system requires to have names for the unbranched chains and next will be the names for the attached simple alkyl groups. Alkyl groups are named by replacing the suffix "-ane" to "-yl".
Here are the most common alkyl groups:
source
And now, we can finally proceed to the IUPAC rules regarding alkane nomenclature. The process begins with:
1. Find the longest chain of the carbon atoms as this will give you the name of the parent chain.
Example:
In the figure below, the longest chain is six carbons therefore the parent chain is hexane.
2. If two chains have the same number of carbons, choose the chain with the most substituents.
3. Number the carbons in the chain starting from the end nearest the first substituent.
Example:
In this structure, we will name the carbons from left to right because is it nearer to the first substituent.
4. If there are substituents that are the same number of carbons in from either end, start the numbering from the end nearest the next substituent
5. Multiplying prefixes are used when a substituent appears more than once. There are also no spaces in the final name.
Example:
There are three instances of the methyl substituent in this alkane therefore it will be called trimethyl.
6. Halogen substituents are given priority in naming
Now that the steps in naming were accomplished, the structure can be correctly named and it is the 2,3,4-trimethylhexane.