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.
|Preferred IUPAC name
3D model (JSmol)
|Molar mass||71.12 g·mol−1|
|Appearance||Clear colorless liquid|
|Melting point||−63 °C (−81 °F; 210 K)|
|Boiling point||87 °C (189 °F; 360 K)|
|Acidity (pKa)||11.27 (pKa of conjugate acid in water),|
19.56 (pKa of conjugate acid in acetonitrile)
|Main hazards||highly flammable, harmful, corrosive, possible mutagen|
|Safety data sheet||MSDS|
|Flash point||3 °C (37 °F; 276 K)|
|345 °C (653 °F; 618 K)|
Related nitrogen heterocyclic compounds
|Pyrrole (aromatic with two double bonds)|
Pyrroline (one double bond)
Pyrrolizidine (two pentagonal rings)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
Synthesis and occurrenceEdit
Pyrrolidine is produced by treatment of 1,4-butanediol with ammonia over an oxide catalyst.
Many modifications of pyrrolidine are found in natural and synthetic chemistry. The pyrrolidine ring structure is present in numerous natural alkaloids such as nicotine and hygrine. It is found in many drugs such as procyclidine and bepridil. It also forms the basis for the racetam compounds (e.g. piracetam, aniracetam). The amino acids proline and hydroxyproline are, in a structural sense, derivatives of pyrrolidine.
Pyrrolidine is a base. Its basicity is typical of other dialkyl amines. Relative to many secondary amines, pyrrolidine is distinctive because of its compactness, a consequence of its cyclic structure.
- Hall, H. K. (1957). "Correlation of the Base Strengths of Amines". Journal of the American Chemical Society. 79 (20): 5441–5444. doi:10.1021/ja01577a030.
- Kaljurand, I.; Kütt, A.; Sooväli, L.; Rodima, T.; Mäemets, V.; Leito, I.; Koppel, I. A. (2005). "Extension of the Self-Consistent Spectrophotometric Basicity Scale in Acetonitrile to a Full Span of 28 pKa Units: Unification of Different Basicity Scales". The Journal of Organic Chemistry. 70 (3): 1019–1028. doi:10.1021/jo048252w. PMID 15675863.
- Pyrrolidine, The Good Scents Company
- Karsten Eller, Erhard Henkes, Roland Rossbacher, Hartmut Höke "Amines, Aliphatic" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. doi:10.1002/14356007.a02_001
- H. K. Hall, Jr. (1957). "Correlation of the Base Strengths of Amines". J. Am. Chem. Soc. 79 (20): 5441. doi:10.1021/ja01577a030.
- R. B. Woodward, I. J. Pachter, and M. L. Scheinbaum (1974). "2,2-(Trimethylenedithio)cyclohexanone". Organic Syntheses. 54: 39. ; Collective Volume, 6, p. 1014
- Media related to Azolidines at Wikimedia Commons