3.1: Amines - Structures and Names

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Learning Objectives

Identify the general structure for an amine.
Identify the functional group for amines.
Determine the structural feature that classifies amines as primary, secondary, or tertiary.
Use nomenclature systems to name amines.

An amine is a derivative of ammonia in which one, two, or all three hydrogen atoms are replaced by hydrocarbon groups.

Key Takeaways.jpg

Amines are classified according to the number of carbon atoms bonded directly to the nitrogen atom. A primary (1°) amine has one alkyl (or aryl) group on the nitrogen atom, a secondary (2°) amine has two, and a tertiary (3°) amine has three (Figure \(\PageIndex{1}\)).

15.5.jpg — Figure \(\PageIndex{1}\): The Structure of Amines Compared to Water, an Alcohol, and an Ether

IMPORTANT: To classify alcohols, we look at the number of carbon atoms bonded to the carbon atom bearing the OH group, not the oxygen atom itself. Thus, although isopropylamine looks similar to isopropyl alcohol, the former is a primary amine, while the latter is a secondary alcohol.

Summary

An amine is a derivative of ammonia in which one, two, or all three hydrogen atoms are replaced by hydrocarbon groups. The amine functional group is as follows:

Amines are classified as primary, secondary, or tertiary by the number of hydrocarbon groups attached to the nitrogen atom.