2-Pyrrolidone
Athanor · official
C4H7NO · 85.1 g/mol
IUPAC name: pyrrolidin-2-one
Also called gamma-butyrolactam, 2-pyrrolidinone, butyrolactam
DangerCauses skin irritation · Causes serious eye damage · Causes serious eye irritation · May cause respiratory irritation · May damage fertility or the unborn child · May damage the unborn childNames and identifiers
- IUPAC name
- pyrrolidin-2-one
- Synonyms
- gamma-butyrolactam, 2-pyrrolidinone, butyrolactam
+ 38 more
2-Pyrrolidinone, pyrrolidin-2-one, Pyrrolidone, Butyrolactam, 2-Oxopyrrolidine, 2-Ketopyrrolidine, 2-Pyrol, gamma-Butyrolactam, Pyrrolidon, alpha-Pyrrolidinone, 4-Aminobutyric acid lactam, gamma-Aminobutyric lactam, gamma-Aminobutyrolactam, alpha-Pyrrolidone, gamma-Aminobutyric acid lactam, Butanoic acid, 4-amino-, lactam, DTXSID8027246, KKL5D39EOL, NSC-4593, NSC-8413, DTXCID707246, FEMA NO. 4829, CHEBI:36592, MELAO Tea TreeShampoo, RefChem:910259, 210-483-1, PYRROLIDINONE, 2-Tetrahydropyrrolone, .alpha.-Pyrrolidone, azacyclopentan-2-one, MFCD00005270, Piracetam EP Impurity A, .gamma.-Aminobutyrolactam, Pyrrolidone-2, pyrrolid-2-one, NSC 4593, NSC 8413, pyrrolidine-2-one
- Molecular formula
- C4H7NO
- Empirical formula
- C4H7NO
- Molecular weight
- 85.1 g/mol
- Exact mass
- 85.05276
- CAS number
- 616-45-5
- PubChem CID
- 12025
- Canonical SMILES
- C1CC(=O)NC1
- Isomeric SMILES
- C1CC(=O)NC1
- InChI
- InChI=1S/C4H7NO/c6-4-2-1-3-5-4/h1-3H2,(H,5,6)
- InChIKey
- HNJBEVLQSNELDL-UHFFFAOYSA-N
- Molfile
Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.
Physical properties
- Appearance
- Light yellow liquid[3]
3 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source – CBI; Liquid [1] EPA Chemical Data Reporting (CDR) – LIGHT YELLOW LIQUID. [2] ILO-WHO International Chemical Safety Cards (ICSCs) –shown Light yellow liquid [3] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 12th ed. New York, NY: Van Nostrand Rheinhold Co., 1993, p. 984 - Melting point
- 25.0 °C[3]
3 values
3 of 3 sources agree on it (most common value).
Value As written Source 25.0 °Cshown 25.0 °C [3] Hazardous Substances Data Bank (HSDB)cites Flick, E.W. (ed.). Industrial Solvents Handbook 4 th ed. Noyes Data Corporation., Park Ridge, NJ., 1991., p. 918 25 °C 25 °C [2] ILO-WHO International Chemical Safety Cards (ICSCs) 24.6 °C 24.6 °C [4] PAC Chemical Database, U.S. Department of Energy - Boiling point
- 245 °C[2]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source 245 °Cshown 245 °C [2] ILO-WHO International Chemical Safety Cards (ICSCs) 245 °C 245 °C @760 [mm Hg] [4] PAC Chemical Database, U.S. Department of Energy - Density
- 1.116 @25 °C[4]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source – Relative density (water = 1): 1.1 [2] ILO-WHO International Chemical Safety Cards (ICSCs) –shown 1.116 @25 °C [4] PAC Chemical Database, U.S. Department of Energy - Solubility in water
- Solubility in water: good[2]
2 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source – Infinitely soluble in water [3] Hazardous Substances Data Bank (HSDB)cites Riddick, J.A., W.B. Bunger, Sakano T.K. Techniques of Chemistry 4th ed., Volume II. Organic Solvents. New York, NY: John Wiley and Sons., 1985., p. 665 –shown Solubility in water: good [2] ILO-WHO International Chemical Safety Cards (ICSCs) - log P
- log Kow= -0.85[3]
- pKa
- pKa= 14.7[3]
- Vapor pressure
- 9.49 × 10⁻³ mmHg @ 25 °C[3]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source 0.00949 mmHgshown 9.49X10-3 mm Hg @ 25 °C [3] Hazardous Substances Data Bank (HSDB)cites Daubert, T.E., R.P. Danner. Physical and Thermodynamic Properties of Pure Chemicals Data Compilation. Washington, D.C.: Taylor and Francis, 1989. 0.00949 mmHg 0.00949 [mm Hg] @25 °C [4] PAC Chemical Database, U.S. Department of Energy 1 more value was reported but failed the checks (unreadable or out of range), so it is not shown.
- Flash point
- 129 °C o.c.[2]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source 129 °C 265 °F (129 °C) (open cup) [3] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 12 ed. Quincy, MA: National Fire Protection Association, 1997., p. 325-83 129 °Cshown 129 °C o.c. [2] ILO-WHO International Chemical Safety Cards (ICSCs)
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
- 6
- Rings
- 1
- Aromatic rings
- 0
- Fraction sp³ carbons (Fsp3)
- 0.75
- H-bond donors
- 1
- H-bond acceptors
- 1
- Rotatable bonds
- 0
- TPSA (Ų)
- 29.1
- Formal charge
- 0
- XLogP3
- -0.8 PubChem
- Complexity
- 69 PubChem
- Stereocenters
- None
- Double-bond geometry
- None specified
- Point group
- C1 of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)
Elemental analysis
- C56.45%
- H8.29%
- N16.46%
- O18.80%
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
- -0.1 Crippen (Wildman and Crippen 1999)
- log S (water solubility)
- -0.3 ESOL (Delaney 2004), log mol/L
- Synthetic accessibility
- 2.38 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)
Drug-likeness: Lipinski’s rule of five
- Molecular weight ≤ 500: 85.11
- log P ≤ 5 (Crippen): -0.1
- 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: 551 company reports to ECHA. Source [5].
- Corrosive
- Harmful or irritant
- Health hazard
- H315Causes skin irritation (17.4% of reports)
- H318Causes serious eye damage (12% of reports)
- H319Causes serious eye irritation (65.7% of reports)
- H335May cause respiratory irritation (12.5% of reports)
- H360May damage fertility or the unborn child (18.1% of reports)
- H360DMay damage the unborn child (24.3% of reports)
Precautionary statements: P203, P261, P264, P264+P265, P271, P280, P302+P352, P304+P340, P305+P351+P338, P305+P354+P338, P317, P318, P319, P321, P332+P317, P337+P317, P362+P364, P403+P233, P405, P501
View all classifications (2)
- [5] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 21.1% (116 of 551) of reports.
- [5] European Chemicals Agency (ECHA) · 551 reports · DangerH315, H318, H319, H335, H360, H360D
First aid
Storage
- Ventilation along the floor.[2]
Safety data sheets on the supplier’s page: Mcule, RR Scientific, abcr GmbH.
Always read the supplier’s safety data sheet before working with it.
Spectra
- NMRHazardous Substances Data Bank (HSDB) · NMRShiftDB
- 1H NMRHuman Metabolome Database (HMDB) (Varian · 500 MHz · CDCl3) · SpectraBase (Varian A-60D)
- 13C NMRSpectraBase
- 15N NMRSpectraBase
- 17O NMRSpectraBase
- 1H-13C NMRHuman Metabolome Database (HMDB) (Bruker · 600 MHz · Water)
- GC-MSHuman Metabolome Database (HMDB) (EI-B · positive) · Human Metabolome Database (HMDB) (EI-B · positive) · Human Metabolome Database (HMDB) (EI-B · positive) · MassBank of North America (MoNA) (HITACHI RMU-6M · EI-B · positive) · MassBank of North America (MoNA) (HITACHI M-80 · EI-B · positive) · MassBank of North America (MoNA) (HITACHI M-80 · EI-B · positive)
- MS-MSHuman Metabolome Database (HMDB) (Quattro_QQQ · Positive) · Human Metabolome Database (HMDB) (Quattro_QQQ · Positive) · Human Metabolome Database (HMDB) (Quattro_QQQ · Positive) · Human Metabolome Database (HMDB) (Positive) · Human Metabolome Database (HMDB) (Positive) · Human Metabolome Database (HMDB) (Positive)
- LC-MSMassBank of North America (MoNA) (Agilent 6550 iFunnel · LC-ESI-QTOF · positive) · MassBank of North America (MoNA) (Agilent 6550 iFunnel · LC-ESI-QTOF · positive) · MassBank of North America (MoNA) (Agilent 6550 iFunnel · LC-ESI-QTOF · positive)
- Other MSHazardous Substances Data Bank (HSDB) · MassBank Europe (HITACHI RMU-6M · EI-B · POSITIVE) · MassBank Europe (HITACHI M-80 · EI-B · POSITIVE) · MassBank of North America (MoNA) (Orbitrap · positive) · MassBank of North America (MoNA) (Orbitrap · positive) · MassBank of North America (MoNA) (Orbitrap · positive)
- 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=5063,REO=2,CNM=HEI,ZFF=2 · NIR Spectrometer= BRUKER IFS 88)
- Vapor Phase IRSpectraBase (DIGILAB FTS-14 · Vapor Phase)
- RamanSpectraBase
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]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
- [2]ILO-WHO International Chemical Safety Cards (ICSCs) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
- [3]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
- [4]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
- [5]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
- [6]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
- [7]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
- [8]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
- [9]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
- [10]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
- [11]MassBank Europe · Linked only · 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.