Naming haloalkanes

Haloalkanes are named as substituted alkanes.
The name contains four parts:  locator(s) prefix(es) stem ending  
meth - 1 carbon
eth - 2 carbons
prop - 3 carbons
but - 4 carbons
pent - 5 carbons
hex - 6 carbons

 

1-chloro-2-methylbutane
 
  1. The ending is -ane
     
  2. The stem used in the name depends on the number of carbons in the longest chain containing the halogen. 

    In the haloalkane at the right, the longest chain containing the carbon bearing halogen has four carbon atoms. 
    Move your mouse over the image to see the origin of this chain.
     
  3. Substituents on the longest chain are included in the name as prefixes.
    Any atom or group of atoms replacing H at a carbon is called a substituent.
     
    bromoBrmethylCH3
    chloroClethylCH3CH2
     
    Note that saturated hydrocarbon substituents have the same name as the parent alkane except with ane substituted by -yl 
     
  4. Each prefix is preceded by a locator indicating the position of that group on the chain.  The functional group in the compound determines the numbering of the chain.
     
    In a haloalkane, the carbon bearing the halogen substituent has the lowest possible number.
    For alkanes the carbon bearing an alkyl substituent has the lowest possible number.

    If two substituents of the same type are present, their name is preceded by di.
    Two locator numbers are given, separated by a comma.

    The compound shown is 1,3-dichlorobutane.
Dr Sheila Woodgate
© The University of Auckland 2002