Amines

Amines are organic compounds that contain nitrogen. They can be thought of as derivatives of ammonia (NH₃) in which one or more hydrogen atoms have been replaced by carbon-containing groups. Amines are important in chemistry and biology — they appear in amino acids, proteins, neurotransmitters, and many pharmaceutical drugs.

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Classification of Amines

Amines are classified according to how many of ammonia's hydrogen atoms have been replaced by alkyl or aryl groups:

• Primary amine (1°): One hydrogen replaced. General formula RNH₂. Example: ethylamine (CH₃CH₂NH₂)
• Secondary amine (2°): Two hydrogens replaced. General formula R₂NH. Example: diethylamine ((CH₃CH₂)₂NH)
• Tertiary amine (3°): All three hydrogens replaced. General formula R₃N. Example: triethylamine ((CH₃CH₂)₃N)

There is also a fourth category — quaternary ammonium ions (R₄N⁺) — where four groups are attached to nitrogen and the species carries a permanent positive charge. These are not amines in the strict sense but are encountered in biological systems and surfactants.

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Naming Amines

Simple amines are named by identifying the alkyl groups attached to nitrogen and adding the suffix -amine:

• CH₃NH₂ — methylamine
• CH₃CH₂NH₂ — ethylamine
• (CH₃)₂NH — dimethylamine
• (CH₃CH₂)₃N — triethylamine
• C₆H₅NH₂ — phenylamine (an aromatic amine)