What is the main difference between primary, secondary, and tertiary amines?

The main difference between primary, secondary, and tertiary amines lies in the number of carbon groups (alkyl or aryl) that are attached to the nitrogen atom. In a primary amine, the nitrogen is bonded to one carbon group and two hydrogen atoms. In a secondary amine, the nitrogen is bonded to two carbon groups and one hydrogen atom. In a tertiary amine, the nitrogen is bonded to three carbon groups with no hydrogen atoms attached.

This classification is significant because it influences the amine's reactivity, the physical properties of the amine, and the types of reactions it can undergo. The presence or absence of specific functional groups, saturation, or hydroxyl groups does not define whether an amine is primary, secondary, or tertiary. Thus, identifying the number of carbon attachments to the nitrogen atom is crucial for categorizing amines correctly.