1. Solubility Test
Primary and secondary amines are generally soluble in water and dilute HCl.
Tertiary amines show lesser solubility in water but dissolve in dilute HCl.
2. Hinsberg Test
Primary amines form soluble sulfonamides in alkali.
Secondary amines form insoluble sulfonamides.
Tertiary amines do not react with Hinsberg's reagent.
3. Nitrous Acid Test
Primary amines generate diazonium salts, decomposing to nitrogen gas and an alcohol or aldehyde.
Secondary amines form yellow-colored N-nitrosoamines.
Tertiary amines show no similar reactivity.
4. Isocyanide Test (Carbylamine Reaction)
Only primary amines react with chloroform and alkali to produce foul-smelling isocyanides.
These tests are essential for distinguishing between primary, secondary, and tertiary aliphatic amines based on their reactivity and solubility properties. here's a table summarizing the qualitative tests for aliphatic amines:
Test | Primary Amines | Secondary Amines | Tertiary Amines |
Solubility Test | Soluble in water and dilute HCl | Soluble in water and dilute HCl (less soluble than primary) | Less soluble in water; soluble in dilute HCl |
Hinsberg Test | Form soluble sulfonamides in alkali | Form insoluble sulfonamides | Do not react |
Nitrous Acid Test | Form diazonium salts, decompose to nitrogen gas and an alcohol or aldehyde | Form yellow-colored N-nitrosoamines | No similar reactivity |
Isocyanide Test (Carbylamine Reaction) | Produce foul-smelling isocyanides | No reaction | No reaction |
This table offers a concise overview of the reactions and outcomes for primary, secondary, and tertiary aliphatic amines when subjected to these tests, helping differentiate between the types of amines based on their chemical behavior.