A primary alcohol is an alcohol which has the hydroxyl group connected to a primary carbon atom. It can also be defined as a molecule containing a “–CH2OH” group. In contrast, a secondary alcohol has a formula “–CHROH” and a tertiary alcohol has a formula “–CR2OH”, where “R” indicates a carbon-containing group.
Examples of primary alcohols include ethanol and butanol.
Some sources include methanol as a primary alcohol, including the 1911 edition of the Encyclopædia Britannica, but this interpretation is less common in modern texts.
The hydroxy group attached to the primary carbon in any primary alcohol is also attached to only one other carbon atom unless it is methanol which is a single carbon molecule bonded to a hydroxy group.