Exam QuestionsRevision NotesVideo TutorialsPast Papers

Amines & Preparation

01Amines & Preparation

Classification of amines

This section covers the classification of primary, secondary and tertiary amines and the distinction between aliphatic and aromatic amines.

Classifying amines

Amines are compounds based on ammonia in which hydrogen atoms have been replaced by alkyl or aryl groups. Whether an amine is primary, secondary or tertiary depends on how many carbon-containing groups are attached directly to its nitrogen atom.

1

Primary amine

One alkyl or aryl group is bonded to nitrogen, leaving two hydrogen atoms on the nitrogen.

Methylamine, CHX3NHX2\ce{CH3NH2}, is a primary amine.

2

Secondary amine

Two alkyl or aryl groups are bonded to nitrogen, leaving one hydrogen atom on the nitrogen.

Dimethylamine, (CHX3)X2NH\ce{(CH3)2NH}, is a secondary amine.

3

Tertiary amine

Three alkyl or aryl groups are bonded to nitrogen, so there is no N–H bond.

Trimethylamine, (CHX3)X3N\ce{(CH3)3N}, is a tertiary amine.

This classification is not assigned in the same way as for alcohols and halogenoalkanes. With amines, it is the substitution around the nitrogen atom that matters.

Aliphatic and aromatic amines

An aliphatic amine has an alkyl group attached to nitrogen.

An aromatic amine has an aryl group attached to nitrogen.

The presence of an aromatic group can substantially affect the chemistry of the amine group, although aliphatic and aromatic amines undergo several similar reactions.

Phenylamine, CX6HX5NHX2\ce{C6H5NH2}, is a primary aromatic amine.

Create a free account to continue

Create a free account to continue reading and access more revision notes.