Alcohols

Return to Contents

Introductory IUPAC Organic Nomenclature

Alcohols

Nomenclature	Formula	3D structure
Functional class name = alkyl alcohol e.g. ethyl alcohol Substituent suffix = -ol e.g. ethanol Substituent prefix = hydroxy- e.g. hydroxyethane Structural unit : alcohols contain R-OH

The root name is based on the longest chain with the -OH attached.
The chain is numbered so as to give the alcohol unit the lowest possible number.
The alcohol suffix is appended after the hydrocarbon suffix minus the "e" : e.g. -ane + -ol = -anol or -ene + ol = -enol.

Functional group is an alcohol, therefore suffix = -ol Hydrocarbon structure is an alkane therefore -ane The longest continuous chain is C3 therefore root = prop It doesn't matter which end we number from, the alcohol group locant is 2- propan-2-ol or 2-propanol (or isopropanol)	CH₃CH(OH)CH₃
Functional group is an alcohol, therefore suffix = -ol Hydrocarbon structure is an alkene therefore -ane The longest continuous chain is C4 therefore root = but The first point of difference rule requires numbering from the right as drawn to make the alcohol group locant 1- butan-1-ol or 1-butanol	CH₃CH₂CH₂CH₂OH

©Dr. Ian Hunt, Department of Chemistry