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Pyrrolidine svg.svg
Preferred IUPAC name
Other names
123-75-1 YesY
3D model (Jmol) Interactive image
ChEBI CHEBI:33135 YesY
ChemSpider 29008 YesY
ECHA InfoCard 100.004.227
PubChem 31268
RTECS number UX9650000
Molar mass 71.12 g·mol−1
Appearance Clear colorless liquid
Density 0.866 g/cm3
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),[1]

19.56 (pKa of conjugate acid in acetonitrile)[2]

-54.8·10−6 cm3/mol
Main hazards highly flammable, harmful, corrosive, possible mutagen
Safety data sheet MSDS
R-phrases R11-R20/21/22-R34[3]
S-phrases S16-S26-S28-S36/37-S45
NFPA 704
Flammability code 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g., gasoline) Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g., calcium Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point 3 °C (37 °F; 276 K)
345 °C (653 °F; 618 K)
Related compounds
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).
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Infobox references

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 an ammonia-like, but characteristic odor.[4] In addition to pyrrolidine itself, many substituted pyrrolidines are known.

Synthesis and occurrence[edit]

Pyrrolidine is produced by treatment of 1,4-butanediol with ammonia over an oxide catalyst.[5]

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.

Nicotine contains an N-methylpyrrolidine ring linked to a pyridine ring.


Pyrrolidine is a base. Its basicity is typical of other dialkyl amines.[6] Relative to many secondary amines, pyrrolidine is distinctive because of its compactness, a consequence of its cyclic structure.

Pyrrolidine is used as a building block in the synthesis of more complex organic compoundsi. It is used to activate ketones and aldehydes toward nucleophilic addition by formation of enamines:[7]



  1. ^ 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. 
  2. ^ 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. 
  3. ^ MSDS
  4. ^ John E. Amoore; L. Janet Forrester; Ron G. Buttery (1975). "Specific anosmia to 1-pyrroline: The spermous primary odor". Journal of Chemical Ecology. 1: 299–310. doi:10.1007/BF00988831. 
  5. ^ 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
  6. ^ H. K. Hall, Jr. (1957). "Correlation of the Base Strengths of Amines". J. Am. Chem. Soc. 79: 5441. doi:10.1021/ja01577a030. 
  7. ^ R. B. Woodward, I. J. Pachter, and M. L. Scheinbaum (1974). "2,2-(Trimethylenedithio)cyclohexanone". Org. Synth. 54: 39.  ; Coll. Vol., 6, p. 1014