Pyrrolidine: Properties, Structure, Preparation And Uses

Pyrrolidine, also known as tetrahydropyrrole, is an organic compound with the molecular formula (CH2)4NH. It is a cyclic secondary amine, also classified as a saturated heterocycle. It is a colourless liquid that is miscible with water and most organic solvents. It has a characteristic odor that has been described as “ammoniacal, fishy, shellfish-like”. In addition to pyrrolidine itself, many substituted pyrrolidines are known.


Chemical FormulaC₄H₉N
Molecular WeightApproximately 71.13 g/mol
StructureFive-membered heterocyclic ring with one nitrogen atom
AppearanceColorless liquid
OdorFishy odor
Boiling Point87-88°C
Melting Point-63 to -65°C
Density0.866 g/cm³ at 20°C
SolubilitySoluble in water, miscible with most organic solvents
StabilityRelatively stable under normal conditions
ReactivityCan undergo various chemical reactions, including nucleophilic substitution

Preparation of Pyrrolidine

Pyrrolidine can be prepared through various synthetic routes. One common method is the reduction of pyrrole, which involves converting the nitrogen atom in pyrrole to an amine group.

Preparation of Pyrrolidine from Pyrrole:

  • Reduction of Pyrrole: Pyrrole (a cyclic compound with five atoms, including one nitrogen) can be reduced to pyrrolidine by reacting it with a reducing agent such as lithium aluminum hydride (LiAlH₄) or sodium borohydride (NaBH₄) in a suitable solvent such as tetrahydrofuran (THF) or diethyl ether.Pyrrole+Reductant→PyrrolidinePyrrole+Reductant→Pyrrolidine
  • Work-Up: After the reaction, the mixture is typically quenched with water or an acidic solution to hydrolyze excess reductant and neutralize any remaining base.
  • Isolation and Purification: Pyrrolidine can be isolated from the reaction mixture by extraction with an organic solvent such as dichloromethane or ethyl acetate. The organic layer containing pyrrolidine is separated and then purified through techniques such as distillation or recrystallization.
  • Characterization: The purity and identity of the isolated pyrrolidine are confirmed using analytical techniques such as NMR spectroscopy, mass spectrometry, and infrared spectroscopy.

Uses of Pyrrolidine

  • Catalyst in organic synthesis reactions
  • Intermediate in pharmaceutical synthesis
  • Solvent for organic and inorganic compounds
  • Corrosion inhibitor in industrial applications
  • Additive in polymerization reactions