Nomenclature of alcohols

• Common system: the word "alcohol" is added after the name of the alkyl group: CH₃OH methyl alcohol, C₂H₅OH ethyl alcohol.
• The prefix iso is used when the chain ends in a carbon bearing two methyl groups and one hydrogen: isopropyl alcohol (CH₃)₂CH–OH.

IUPAC system: take the longest chain containing the carbon that carries –OH, change -e of the alkane to -ol, and number from the end nearest the –OH; put the number of the carbon holding –OH before the name:

• CH₃OH methanol; C₂H₅OH ethanol; CH₃CH₂CH₂OH 1-propanol (n-propyl alcohol); CH₃CH(OH)CH₃ 2-propanol (isopropyl alcohol).
• The three alcohol isomers derived from pentane: 1-pentanol, 2-pentanol, 3-pentanol (and there are others from branched chains: for example 2,2-dimethyl-1-propanol).
• Other examples: (CH₃)₂CHCH₂OH 2-methyl-1-propanol; 2,2-dimethyl-1-butanol is CH₃CH₂C(CH₃)₂CH₂OH; isopentyl alcohol (CH₃)₂CHCH₂CH₂OH (3-methyl-1-butanol).