Caprolactam

Athanor · official

C₆H₁₁NO · 113.16 g/mol

IUPAC name: azepan-2-one

Also called nylon 6 monomer, hexano-6-lactam, azepan-2-one

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Drawn from its SMILES with RDKit

WarningHarmful if swallowed · Causes skin irritation · Causes serious eye irritation · Harmful if inhaled · May cause respiratory irritation

Names and identifiers

IUPAC name: azepan-2-one
Synonyms: nylon 6 monomer, hexano-6-lactam, azepan-2-one
+ 37 more
epsilon-Caprolactam, 2-Oxohexamethylenimine, 6-Caprolactam, Aminocaproic lactam, Hexahydro-2H-azepin-2-one, 6-Hexanelactam, 2-Oxohexamethyleneimine, 2-Azacycloheptanone, Hexanolactam, 2H-Azepin-2-one, hexahydro-, Hexahydro-2-azepinone, 2-Perhydroazepinone, 1,6-Hexolactam, Hexanone isoxime, Hexanonisoxim, Caprolattame, 2-Ketohexamethylenimine, Cyclohexanone iso-oxime, 2-Ketohexamethyleneimine, 1-Aza-2-cycloheptanone, Caprolactam monomer, Epsylon kaprolaktam, 6-Aminocaproic acid lactam, Extrom 6N, Kapromine, hexannic acid, Stilon, e-Kaprolaktam, Hexamethylenimine, 2-oxo-, 1,6-Hexalactam, Capron PK4, 6-Aminohexanoic acid cyclic lactam, 2H-Azepin-7-one, hexahydro-, gamma-caprolactam, Hexanoic acid, 6-amino-, lactam, NCI-C50646, Hexanoic acid, 6-amino-, cyclic lactam
Molecular formula: C₆H₁₁NO
Empirical formula: C₆H₁₁NO
Molecular weight: 113.16 g/mol
Exact mass: 113.08406
CAS number: 105-60-2
PubChem CID: 7768
Canonical SMILES: C1CCC(=O)NCC1
Isomeric SMILES: C1CCC(=O)NCC1
InChI: InChI=1S/C6H11NO/c8-6-4-2-1-3-5-7-6/h1-5H2,(H,7,8)
InChIKey: JBKVHLHDHHXQEQ-UHFFFAOYSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Physical properties

TemperaturePressureDensity

Appearance: White flakes or fused[6]
7 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Caprolactam is a clear to milky white-colored solution with a mild, disagreeable odor. Contact may cause slight irritation to skin, eyes, and mucous membranes. May be mildly toxic by ingestion. The primary hazard is the threat to the environment. Immediate steps should be taken to limit its spread to the environment. As a liquid it can easily penetrate the soil and contaminate groundwater and nearby streams. Used to make other chemicals. [1] CAMEO Chemicals
– Large Crystals; CBI; Large Crystals; Liquid; Liquid; Liquid; Other Solid [2] EPA Chemical Data Reporting (CDR)
– WHITE HYGROSCOPIC CRYSTALS OR FLAKES. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– Clear to milky white-colored solution with a mild, disagreeable odor. [4] Occupational Safety and Health Administration (OSHA)
– White, crystalline solid or flakes with an unpleasant odor. [Note: Significant vapor concentrations would be expected only at elevated temperatures.] [5] The National Institute for Occupational Safety and Health (NIOSH)
– White, crystalline solid or flakes ... [Note: Significant vapor concentrations would be expected only at elevated temperatures]. [6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997., p. 50
–shown White flakes or fused [6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 13th ed. New York, NY: John Wiley & Sons, Inc. 1997., p. 205
Odor: ... Unpleasant odor ...[6]
Melting point: 69.3 °C[7]
5 values
5 of 5 sources agree on it (most common value).
Value As written Source
69 °C 156 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
70 °C 70 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
69 °C 156 °F [4] Occupational Safety and Health Administration (OSHA)
69.3 °Cshown 69.3 °C [7] PAC Chemical Database, U.S. Department of Energy
69 °C 156 °F [5] The National Institute for Occupational Safety and Health (NIOSH)
Boiling point: 266.9 °C (512.4 °F) at 760 mmHg (NTP, 1992)[1]
5 values
4 of 5 sources agree on it (most common value).
Value As written Source
266.9 °Cshown 512.4 °F at 760 mmHg (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
267 °C 267 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
268 °C 515 °F [4] Occupational Safety and Health Administration (OSHA)
270 °C 270 °C @760 [mm Hg] [7] PAC Chemical Database, U.S. Department of Energy
268 °C 515 °F [5] The National Institute for Occupational Safety and Health (NIOSH)
Density: 1.02 @ 75°C in Liquid form[7]
5 values
5 of 5 sources agree on it (most common value).
Value As written Source
– 1.02 at 170.6 °F (USCG, 1999) - Denser than water [1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
– Relative density (water = 1): 1.02 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– 1.02 [4] Occupational Safety and Health Administration (OSHA)
–shown 1.02 @ 75°C in Liquid form [7] PAC Chemical Database, U.S. Department of Energy
– 1.01 [5] The National Institute for Occupational Safety and Health (NIOSH)
Solubility in water: Solubility in water: good[3]
5 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source
– greater than or equal to 100 mg/mL at 68.9 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
– Soluble in chlorinated solvents, petroleum distillate, and cyclohexene. [6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 13th ed. New York, NY: John Wiley & Sons, Inc. 1997., p. 205
– In water, 5.25X10+6 mg/l @ 25 °C. [6] Hazardous Substances Data Bank (HSDB)cites Loewengart G; pp. 36-52 in Proc Symp Ind Approach Chem Risk Assess: Caprolactam Relat Compd Case Study, Arlington, VA: Marriott-Crystal Gateway (1984)
–shown Solubility in water: good [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– 53% [5] The National Institute for Occupational Safety and Health (NIOSH)
log P: -0.19[3]
Vapor pressure: Vapor pressure, Pa at 25 °C: 0.26[3]
5 values
2 of 3 sources agree on it (most common value).
Value As written Source
0.001 mmHg 0.001 mmHg at 68 °F [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
3 mmHg 3 mmHg at 212 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
6 mmHg Vapor pressure: 6 mm Hg @ 120 °C [6] Hazardous Substances Data Bank (HSDB)cites Sax, N.I. Dangerous Properties of Industrial Materials. 6th ed. New York, NY: Van Nostrand Reinhold, 1984., p. 1515
0.0019 mmHg 1.9X10-3 mm Hg at 25 °C [6] Hazardous Substances Data Bank (HSDB)cites Jones AH; J Chem Eng Data 5: 196-200 (1960)
0.002 mmHgshown Vapor pressure, Pa at 25 °C: 0.26 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
2 more values were reported but failed the checks (unreadable or out of range), so they are not shown.
Flash point: 125 °C o.c.[3]
4 values
2 of 4 sources agree on it (most common value).
Value As written Source
125 °C 257 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
125 °Cshown 125 °C o.c. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
139 °C 282 °F [4] Occupational Safety and Health Administration (OSHA)
139 °C 282 °F [5] The National Institute for Occupational Safety and Health (NIOSH)
Autoignition temperature: 375 °C[3]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source
375 °C 707 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
375 °Cshown 375 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
–	Caprolactam is a clear to milky white-colored solution with a mild, disagreeable odor. Contact may cause slight irritation to skin, eyes, and mucous membranes. May be mildly toxic by ingestion. The primary hazard is the threat to the environment. Immediate steps should be taken to limit its spread to the environment. As a liquid it can easily penetrate the soil and contaminate groundwater and nearby streams. Used to make other chemicals.	[1] CAMEO Chemicals
–	Large Crystals; CBI; Large Crystals; Liquid; Liquid; Liquid; Other Solid	[2] EPA Chemical Data Reporting (CDR)
–	WHITE HYGROSCOPIC CRYSTALS OR FLAKES.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	Clear to milky white-colored solution with a mild, disagreeable odor.	[4] Occupational Safety and Health Administration (OSHA)
–	White, crystalline solid or flakes with an unpleasant odor. [Note: Significant vapor concentrations would be expected only at elevated temperatures.]	[5] The National Institute for Occupational Safety and Health (NIOSH)
–	White, crystalline solid or flakes ... [Note: Significant vapor concentrations would be expected only at elevated temperatures].	[6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997., p. 50
–shown	White flakes or fused	[6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 13th ed. New York, NY: John Wiley & Sons, Inc. 1997., p. 205

Value	As written	Source
69 °C	156 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
70 °C	70 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
69 °C	156 °F	[4] Occupational Safety and Health Administration (OSHA)
69.3 °Cshown	69.3 °C	[7] PAC Chemical Database, U.S. Department of Energy
69 °C	156 °F	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
266.9 °Cshown	512.4 °F at 760 mmHg (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
267 °C	267 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
268 °C	515 °F	[4] Occupational Safety and Health Administration (OSHA)
270 °C	270 °C @760 [mm Hg]	[7] PAC Chemical Database, U.S. Department of Energy
268 °C	515 °F	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
–	1.02 at 170.6 °F (USCG, 1999) - Denser than water	[1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
–	Relative density (water = 1): 1.02	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	1.02	[4] Occupational Safety and Health Administration (OSHA)
–shown	1.02 @ 75°C in Liquid form	[7] PAC Chemical Database, U.S. Department of Energy
–	1.01	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
–	greater than or equal to 100 mg/mL at 68.9 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–	Soluble in chlorinated solvents, petroleum distillate, and cyclohexene.	[6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 13th ed. New York, NY: John Wiley & Sons, Inc. 1997., p. 205
–	In water, 5.25X10+6 mg/l @ 25 °C.	[6] Hazardous Substances Data Bank (HSDB)cites Loewengart G; pp. 36-52 in Proc Symp Ind Approach Chem Risk Assess: Caprolactam Relat Compd Case Study, Arlington, VA: Marriott-Crystal Gateway (1984)
–shown	Solubility in water: good	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	53%	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
0.001 mmHg	0.001 mmHg at 68 °F	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
3 mmHg	3 mmHg at 212 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
6 mmHg	Vapor pressure: 6 mm Hg @ 120 °C	[6] Hazardous Substances Data Bank (HSDB)cites Sax, N.I. Dangerous Properties of Industrial Materials. 6th ed. New York, NY: Van Nostrand Reinhold, 1984., p. 1515
0.0019 mmHg	1.9X10-3 mm Hg at 25 °C	[6] Hazardous Substances Data Bank (HSDB)cites Jones AH; J Chem Eng Data 5: 196-200 (1960)
0.002 mmHgshown	Vapor pressure, Pa at 25 °C: 0.26	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
125 °C	257 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
125 °Cshown	125 °C o.c.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
139 °C	282 °F	[4] Occupational Safety and Health Administration (OSHA)
139 °C	282 °F	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
375 °C	707 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
375 °Cshown	375 °C	[3] 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: 8
Rings: 1
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 0.83
H-bond donors: 1
H-bond acceptors: 1
Rotatable bonds: 0
TPSA (Å²): 29.1
Formal charge: 0
XLogP3: -0.1 PubChem
Complexity: 90 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

C63.69%
H9.80%
N12.38%
O14.14%

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: 0.68 Crippen (Wildman and Crippen 1999)
log S (water solubility): -0.97 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 2.13 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 113.16
log P ≤ 5 (Crippen): 0.68
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

Warning

Harmonized EU classification (CLP Annex VI). Source [8].

Harmful or irritant

H302Harmful if swallowed
H315Causes skin irritation
H319Causes serious eye irritation
H332Harmful if inhaled
H335May cause respiratory irritation

Precautionary statements: P261, P264, P264+P265, P270, P271, P280, P301+P317, P302+P352, P304+P340, P305+P351+P338, P317, P319, P321, P330, P332+P317, P337+P317, P362+P364, P403+P233, P405, P501

View all classifications (3)

[8] Regulation (EC) No 1272/2008 of the European Parliament and of the Council · WarningH302, H315, H319, H332, H335
[9] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for < 0.1% (1 of 1874) of reports.
[9] European Chemicals Agency (ECHA) · 1,874 reports · WarningH302, H315, H319, H332, H335

Exposure limits

PEL: None See Appendix G[5]
REL-TWA (Time Weighted Average): 1 mg/m³ (dust), 0.22 ppm (1 mg/m³) (vapor)[4]
REL: Dust: TWA 1 mg/m3 ST 3 mg/m3 Vapor: TWA 0.22 ppm (1 mg/m3) ST 0.66 ppm (3 mg/m3)[5]
TLV: 5 mg/m[3]
TLV-TWA (Time Weighted Average): 5 mg/m³ (inhalable fraction and vapor) [1997][4]
IDLH: N.D. See: IDLH index[5]

First aid

Eyes: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. Immediately transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop. Skin: Immediately flood affected skin with water while removing and isolating all contaminated clothing.[1]
(General first aid procedures) Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately. Skin: Water wash immediately - If this chemical contacts the skin, immediately wash the contaminated skin with water. If this chemical penetrates the clothing, immediately remove the clothing and wash the skin with water.[5]
Fresh air, rest. Refer for medical attention.[3]
Remove contaminated clothes. Rinse skin with plenty of water or shower.[3]

Storage

Separated from strong oxidants. Dry.[3]

Incompatibilities

Strong oxidizers, (acetic acid + dinitrogen trioxide).[6]
During preparation of the N-nitroso derivative from the lactam in acetic acid solution, the treatment with dinitrogen trioxide must be very effectively cooled to prevent explosive decomposition.[6]
Strong oxidizers, (acetic acid + dinitrogen trioxide)[5]

Safety data sheets on the supplier’s page: Smolecule, Accel Scientific, CATO Research Chemicals Inc..

Always read the supplier’s safety data sheet before working with it.

Spectra

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]Occupational Safety and Health Administration (OSHA) · Public domain (US DOL) · via PubChem · retrieved 2026-10-14
[5]The National Institute for Occupational Safety and Health (NIOSH) · Public domain (US CDC) · via PubChem · retrieved 2026-10-14
[6]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[7]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
[8]Regulation (EC) No 1272/2008 of the European Parliament and of the Council · EU reuse policy, CC BY 4.0 · via PubChem · retrieved 2026-10-14
[9]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[10]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
[11]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[12]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[13]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[14]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[15]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.