Rules for naming alkanes or nomenclature of alkanes

(a) Names of straight chain isomers alkanes

Straight chain isomers are named according to the number of carbon atoms in the chain.

(a) Naming branched chain alkanes

(i) Determine the number of carbon atoms in the longest carbon chain that contain the branch.

(ii) Number the carbon atoms from the side nearest the branch.

Example

(iii) If there more than one similar alkyl groups on the longest chain; use di, tri, tetra to indicate the number of such groups on the main chain.

Example

Note that 

• This name implies that there is a methyl group attached to carbon 2 and another to carbon 3 of the butane.
• When writing the name of organic compound, a coma (,) is placed between figures and a dash (-) between a figure and a letter.

(iv) If different branches name them alphabetically

Example

Note that

“E” for ethyl group comes before “M” for methyl group in the alphabets.

 

(v) If branching occurs equal distance from either side, choose a name that gives the least sum of combination of numbers.

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