General

What is the IUPAC convention for naming alkanes?

1. Find and name the longest continuous carbon chain.
2. Identify and name substituent groups attached to this chain.
3. Number the chain consecutively, starting at the end nearest the longest (or largest) substituent group.
4. Designate the location of each substituent group by the appropriate number and name. The prefixes di-, tri-, tetra- etc., are used to distinguish similar substituent groups.
5. Finish the name, listing groups in alphabetical order.

The suffix for alkanes is -ane and the common prefixes for organic molecules such as meth-, eth-, prop-, etc. apply. Unbranched alkanes are denoted with an n- - see table 42.1 below.

Table 42.1: Common alkanes.

methane	$CH_{4}$	$n-$pentane	$CH_{3}(CH_{2})_{3}CH_{3}$
ethane	$C_{2}H_{6}$	$n-$hexane	$CH_{3}(CH_{2})_{4}CH_{3}$
propane	$C_{3}H_{8}$	$n-$hepane	$CH_{3}(CH_{2})_{5}CH_{3}$
$n-$butane	$C_{4}H_{10}$	$n-$octane	$CH_{3}(CH_{2})_{6}CH_{3}$

What are some examples of common alkane substituent groups and branched alkanes?

Table 42.2: Common substituent alkane groups.

methyl	$CH_{3}-$	butyl	$CH_{3}CH_{2}CH_{2}CH_{2}-$
ethyl	$C_{2}H_{5}-$	isobutyl	$(CH_{3})_{2}CHCH_{2}-$
propyl	$CH_{3}CH_{2}CH_{2}-$	sec-butyl	$CH_{3}CH_{2}CH(CH_{3})-$
isopropyl	$(CH_{3})_{2}CH-$	$tert$-butyl	$(CH_{3})3C-$

Figure 42.2: Examples of branched alkanes: (a) t-butane (isobutane), (b) neopentane, and (c) isopentane.