Pyrrolidine
Athanor · official
C4H9N · 71.12 g/mol
Also called tetrahydropyrrole, azolidine
DangerHighly Flammable liquid and vapor · Harmful if swallowed · Causes severe skin burns and eye damage · Causes serious eye damage · Harmful if inhaledNames and identifiers
- IUPAC name
- pyrrolidine
- Synonyms
- tetrahydropyrrole, azolidine, Tetrahydropyrrole
+ 36 more
Azacyclopentane, Azolidine, Tetramethylenimine, Butylenimine, Prolamine, Perhydropyrrole, 1-Azacyclopentane, Pyrrolidine ring, Pyrrole, tetrahydro-, FEMA No. 3523, LJU5627FYV, NSC-62781, DTXSID3059559, CHEBI:33135, Pyrrole, tetrahydro, RefChem:6189, DTXCID6033796, 204-648-7, Tetrahydro pyrrole, Tetramethyleneimine, MFCD00005249, NSC 62781, CHEMBL22830, pyrrolidin, CCRIS 6688, HSDB 120, EINECS 204-648-7, UN1922, UNII-LJU5627FYV, BRN 0102395, pyrolidine, pyrollidine, pyrroldine, pyrrolodine, Pirrolidine, Pyrrollidine
- Molecular formula
- C4H9N
- Empirical formula
- C4H9N
- Molecular weight
- 71.12 g/mol
- Exact mass
- 71.07350
- CAS number
- 123-75-1
- PubChem CID
- 31268
- Canonical SMILES
- C1CCNC1
- Isomeric SMILES
- C1CCNC1
- InChI
- InChI=1S/C4H9N/c1-2-4-5-3-1/h5H,1-4H2
- InChIKey
- RWRDLPDLKQPQOW-UHFFFAOYSA-N
- Molfile
Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.
Physical properties
- Appearance
- Colorless to pale yellow liq[4]
4 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source – Pyrrolidine appears as a colorless to pale yellow liquid with an ammonia-like odor. Vapors heavier than air. Produces toxic oxides of nitrogen during combustion. [1] CAMEO Chemicals – Liquid [2] EPA Chemical Data Reporting (CDR) – COLOURLESS-TO-YELLOW LIQUID WITH PUNGENT ODOUR. [3] ILO-WHO International Chemical Safety Cards (ICSCs) –shown Colorless to pale yellow liq [4] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 14th Edition. John Wiley & Sons, Inc. New York, NY 2001., p. 943 - Melting point
- -63 °C[3]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source −63 °Cshown -63 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs) −63 °C -63 °C [5] PAC Chemical Database, U.S. Department of Energy - Boiling point
- 89 °C[3]
- Density
- 0.8618 @25 °C[5]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source – Relative density (water = 1): 0.85 [3] ILO-WHO International Chemical Safety Cards (ICSCs) –shown 0.8618 @25 °C [5] PAC Chemical Database, U.S. Department of Energy - Solubility in water
- Solubility in water: miscible[3]
2 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source – In water, 1.0X10+6 mg/L (miscible) at 20 °C [4] Hazardous Substances Data Bank (HSDB)cites Yalkowsky SH, Dannenfelser RM; The AQUASOL dATAbASE of Aqueous Solubility. Fifth ed, Tucson, AZ: Univ Az, College of Pharmacy (1992) –shown Solubility in water: miscible [3] ILO-WHO International Chemical Safety Cards (ICSCs) - log P
- 0.46[3]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source – log Kow = 0.46 at pH 13 [4] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 10 –shown 0.46 [3] ILO-WHO International Chemical Safety Cards (ICSCs) - pKa
- pKa = 11.31[4]
- Vapor pressure
- 128 [mmHg] @39 °C[5]
2 values
Sources disagree; from PAC Chemical Database, U.S. Department of Energy, the most authoritative.
Value As written Source 14 mmHg Vapor pressure, kPa at 39 °C: 1.8 [3] ILO-WHO International Chemical Safety Cards (ICSCs) 128 mmHgshown 128 [mm Hg] @39 °C [5] PAC Chemical Database, U.S. Department of Energy - Flash point
- 3 °C[3]
3 values
3 of 3 sources agree on it (most common value).
Value As written Source 3 °C 37 °F (NFPA, 2010) [1] CAMEO Chemicalscites National Fire Protection Association. 2010. Fire Protection Guide to Hazardous Materials, 14th edition, edited by Guy R. Colonna. Quincy, MA: National Fire Protection Association. Note that this information is subject to the copyright restrictions of the organization that provided the data. 3 °C 37 °F (3 °C) (CLOSED CUP) [4] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-103 3 °Cshown 3 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs) - Viscosity
- Reported, but no value passed the checks.
The value and why
- 6.1472X10-3 Pa.s (no temperature given; source [4])
Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.
Calculated
- Heavy atoms
- 5
- Rings
- 1
- Aromatic rings
- 0
- Fraction sp³ carbons (Fsp3)
- 1
- H-bond donors
- 1
- H-bond acceptors
- 1
- Rotatable bonds
- 0
- TPSA (Ų)
- 12
- Formal charge
- 0
- XLogP3
- 0.5 PubChem
- Complexity
- 22 PubChem
- Stereocenters
- None
- Double-bond geometry
- None specified
- Point group
- Cs of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)
Elemental analysis
- C67.55%
- H12.76%
- N19.69%
Isotope pattern
Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.
Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.
Predicted
- log P
- 0.37 Crippen (Wildman and Crippen 1999)
- log S (water solubility)
- -0.51 ESOL (Delaney 2004), log mol/L
- Synthetic accessibility
- 2.19 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)
Drug-likeness: Lipinski’s rule of five
- Molecular weight ≤ 500: 71.12
- log P ≤ 5 (Crippen): 0.37
- H-bond donors ≤ 5: 1
- H-bond acceptors ≤ 10: 1
Passes all four rules.
¹³C NMR shifts, predicted
Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.
Safety
Danger
Most widely reported: 1,650 company reports to ECHA. Source [6].
- Flammable
- Corrosive
- Harmful or irritant
- H225Highly Flammable liquid and vapor (22% of reports)
- H302Harmful if swallowed (99.5% of reports)
- H314Causes severe skin burns and eye damage
- H318Causes serious eye damage (13% of reports)
- H332Harmful if inhaled (99.8% of reports)
Precautionary statements: P210, P233, P240, P241, P242, P243, P260, P261, P264, P264+P265, P270, P271, P280, P301+P317, P301+P330+P331, P302+P361+P354, P303+P361+P353, P304+P340, P305+P354+P338, P316, P317, P321, P330, P363, P370+P378, P403+P235, P405, P501
First aid
- Excerpt from ERG Guide 132 [Flammable Liquids - Corrosive]: Refer to the "General First Aid" section. Specific First Aid: For corrosives, in case of contact, immediately flush skin or eyes with running water for at least 30 minutes. Additional flushing may be required. In case of burns, immediately cool affected skin for as long as possible with cold water. Do not remove clothing if adhering to skin. (ERG, 2024)[1]
- General First Aid: · Call 911 or emergency medical service. · Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination. · Move victim to fresh air if it can be done safely. · Administer oxygen if breathing is difficult. · If victim is not breathing: -- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance. -- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped…[7]
- Fresh air, rest. Refer for medical attention.[3]
- Rinse skin with plenty of water or shower. Refer for medical attention .[3]
Storage
Incompatibilities
Safety data sheets on the supplier’s page: A2B Chem, VladaChem, Molport.
Always read the supplier’s safety data sheet before working with it.
Spectra
- NMRHazardous Substances Data Bank (HSDB) · NMRShiftDB
- 1H NMRSpectraBase (Varian A-60)
- 13C NMRHazardous Substances Data Bank (HSDB) · SpectraBase
- 15N NMRSpectraBase
- GC-MSNIST Mass Spectrometry Data Center · NIST Mass Spectrometry Data Center · NIST Mass Spectrometry Data Center · SpectraBase (GC/MS)
- MS-MSHuman Metabolome Database (HMDB) (QTOF · positive) · Human Metabolome Database (HMDB) (QTOF · positive) · Human Metabolome Database (HMDB) (QTOF · positive) · Human Metabolome Database (HMDB) (QTOF · positive) · Human Metabolome Database (HMDB) (QTOF · positive) · Human Metabolome Database (HMDB) (QTOF · positive)
- LC-MSMassBank of North America (MoNA) (Agilent 6550 iFunnel · LC-ESI-QTOF · ESI) · MassBank of North America (MoNA) (Agilent 6550 iFunnel · LC-ESI-QTOF · ESI) · MassBank of North America (MoNA) (Agilent 6550 iFunnel · LC-ESI-QTOF · ESI)
- Other MSHazardous Substances Data Bank (HSDB)
- UVHazardous Substances Data Bank (HSDB)
- IRHazardous Substances Data Bank (HSDB)
- FTIRSpectraBase (Bio-Rad FTS · Neat (KBr))
- ATR-IRSpectraBase (PerkinElmer SpectrumTwo · ATR-IR)
- Near IRSpectraBase (INSTRUMENT PARAMETERS=INST=BRUKER,RSN=9130,REO=2,CNM=HEI,ZFF=2 · NIR Spectrometer= BRUKER IFS 88)
- Vapor Phase IRSpectraBase (Bruker IFS 85 · Gas-GC)
- RamanHazardous Substances Data Bank (HSDB) · SpectraBase (Bruker MultiRAM Stand Alone FT-Raman Spectrometer · FT-Raman)
Experimental spectra held by these sources; each link opens the source's own record.
Literature
Reading PubChem, OpenAlex and GSRS…
Bioactivity
Reading ChEMBL…
References
- [1]CAMEO Chemicals · Public domain (NOAA) · via PubChem · retrieved 2026-10-14
- [2]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
- [3]ILO-WHO International Chemical Safety Cards (ICSCs) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
- [4]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
- [5]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
- [6]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
- [7]Emergency Response Guidebook (ERG) · Public domain (US DOT) · via PubChem · retrieved 2026-10-14
- [8]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
- [9]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
- [10]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
- [11]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
- [12]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
- ·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
- ·Literature on PubChem
Data last updated 2026-10-14.