CAS number  YesY
ChemSpider  YesY
RTECS number UX9650000
Jmol-3D images Image 1
Molecular formula C4H9N
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)
Solubility in water Miscible
Acidity (pKa) 11.27 (pKa of conjugate acid in water),[1]

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

R-phrases R11-R20/21/22-R34[3]
S-phrases S16-S26-S28-S36/37-S45
Main hazards highly flammable, harmful, corrosive, possible mutagen
NFPA 704
Flash point 3 °C (37 °F; 276 K)
Related compounds
Related Nitrogen heterocyclic compounds Pyrrole (aromatic with two double bonds)
Pyrroline (one double bond)
Pyrrolizidine (two pentagonal rings)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY   YesY/N?)

Pyrrolidine, also known as tetrahydropyrrole, is an [4] Compared to acyclic secondary amines, it is about 10 times more basic.

Synthesis and occurrence

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

Pyrrolidine is found in the leaves of tobacco and carrot. The pyrrolidine ring structure is present in numerous natural alkaloids such as nicotine and hygrine. It is found in many pharmaceutical 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 used as a building block in the synthesis of more complex compounds. In organic chemistry, pyrrolidine is used to activate ketones and aldehydes toward nucleophilic addition by formation of enamines:[6]


  1. ^ Hall, H. K. (1957). "Correlation of the Base Strengths of Amines". Journal of the American Chemical Society 79 (20): 5441.  
  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.  
  3. ^ MSDS
  4. ^ Journal of Chemical Ecology 1 (3): 299–310. 
  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. ^