Aliphatic amines are organic compounds featuring a nitrogen atom with a lone pair of electrons, attached to alkyl or cycloalkyl groups.
They belong to the broader category of amines, which are divided into aliphatic and aromatic amines based on the nature of the hydrocarbon group linked to the nitrogen.
Classification
Aliphatic amines are classified according to the number of alkyl groups bonded to the nitrogen atom:
Primary (1°) Amines:
Nitrogen is bonded to one alkyl group and two hydrogen atoms.
General formula: RNH₂, where R represents an alkyl group.
Example: Methylamine (CH₃NH₂).
Secondary (2°) Amines:
Nitrogen is bonded to two alkyl groups and one hydrogen atom.
General formula: R₂NH.
Example: Dimethylamine [(CH₃)₂NH].
Tertiary (3°) Amines:
Nitrogen is bonded to three alkyl groups with no hydrogen atoms directly attached.
General formula: R₃N.
Example: Trimethylamine [(CH₃)₃N].
Quaternary (4°) Ammonium Salts:
Nitrogen is bonded to four alkyl groups, resulting in a positively charged ion.
General formula: R₄N⁺X⁻, where X denotes an anion.