Caproic acid

Athanor · official

C₆H₁₂O₂ · 116.16 g/mol

IUPAC name: hexanoic acid

Also called hexanoic acid, C6:0, caproate

Lipids

Open in Athanor

Drawn from its SMILES with RDKit

DangerToxic in contact with skin · Causes serious eye damage

Names and identifiers

IUPAC name: hexanoic acid
Synonyms: hexanoic acid, C6:0, caproate
+ 38 more
HEXANOIC ACID, n-Caproic acid, n-Hexanoic acid, Capronic acid, 1-Hexanoic acid, Hexoic acid, Butylacetic acid, Pentylformic acid, n-Hexylic acid, n-Hexoic acid, Pentiformic acid, 1-Pentanecarboxylic acid, Hexylic acid, Pentanecarboxylic acid, Hexacid 698, Kyselina kapronova, FEMA No. 2559, DTXSID7021607, 1F8SN134MX, NSC8266, NSC-8266, DTXCID101607, CHEBI:30776, NSC-35598, Bi(OHex)3, fatty acid 6:0, RefChem:31611, 205-550-7, Acid C6, NSC 8266, MFCD00004421, hexanoic acid (caproic acid), Acid C6; Caproic acid, NCIOpen2_005355, CHEMBL14184, CH3-[CH2]4-COOH, FA 6:0, HEXANOIC ACID (CAPROIC ACID)
Molecular formula: C₆H₁₂O₂
Empirical formula: C₃H₆O
Molecular weight: 116.16 g/mol
Exact mass: 116.08373
CAS number: 142-62-1
PubChem CID: 8892
Canonical SMILES: CCCCCC(=O)O
Isomeric SMILES: CCCCCC(=O)O
InChI: InChI=1S/C6H12O2/c1-2-3-4-5-6(7)8/h2-5H2,1H3,(H,7,8)
InChIKey: FUZZWVXGSFPDMH-UHFFFAOYSA-N
Molfile

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

Physical properties

TemperaturePressureDensity

Appearance: Oily liquid[4]
4 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Caproic acid appears as a white crystalline solid or colorless to light yellow solution with an unpleasant odor. Insoluble to slightly soluble in water and less dense than water. Contact may severely irritate skin, eyes and mucous membranes. May be toxic by ingestion, inhalation and skin absorption. Used to make perfumes. [1] CAMEO Chemicals
– Liquid; Liquid; Other Solid [2] EPA Chemical Data Reporting (CDR)
– OILY COLOURLESS LIQUID WITH CHARACTERISTIC ODOUR. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
–shown Oily liquid [4] Hazardous Substances Data Bank (HSDB)cites Verschueren, K. Handbook of Environmental Data on Organic Chemicals. Volumes 1-2. 4th ed. John Wiley & Sons. New York, NY. 2001, p. 423
Melting point: -3 °C[3]
4 values
4 of 4 sources agree on it (most common value).
Value As written Source
−3 °C 27 °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.
−3.4 °C -3.4 °C [4] Hazardous Substances Data Bank (HSDB)cites Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present., p. V5: 149 (1993)
−3 °Cshown -3 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
−3 °C -3 °C [5] PAC Chemical Database, U.S. Department of Energy
Boiling point: 205.8 °C[4]
4 values
3 of 4 sources agree on it (most common value).
Value As written Source
202 to 203 °C 396 to 397 °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.
205.8 °Cshown 205.8 °C [4] Hazardous Substances Data Bank (HSDB)cites Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present., p. V5: 149 (1993)
205 °C 205 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
205 °C 205 °C @760 [mm Hg] [5] PAC Chemical Database, U.S. Department of Energy
Density: 0.929 at 20 °C/4 °C[4]
4 values
Only one source reports it.
Value As written Source
– 0.927 (USCG, 1999) - Less dense 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.
0.929 g/mLshown 0.929 at 20 °C/4 °C [4] Hazardous Substances Data Bank (HSDB)cites Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present., p. V5: 149 (1993)
– Relative density (water = 1): 0.93 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– 0.9295 @25 °C [5] PAC Chemical Database, U.S. Department of Energy
Solubility in water: Solubility in water, g/100ml at 20 °C: 1.1[3]
3 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source
– 5 to 10 mg/mL at 72 °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.
– In water, 1.03X10+4 mg/L at 25 °C [4] Hazardous Substances Data Bank (HSDB)cites Yalkowsky, S.H., He, Yan., Handbook of Aqueous Solubility Data: An Extensive Compilation of Aqueous Solubility Data for Organic Compounds Extracted from the AQUASOL dATAbASE. CRC Press LLC, Boca Raton, FL. 2003., p. 305
–shown Solubility in water, g/100ml at 20 °C: 1.1 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
log P: 1.88[3]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source
– log Kow = 1.92 [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. 24
–shown 1.88 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
pKa: pKa = 4.88[4]
Vapor pressure: Vapor pressure, Pa at 20 °C: 27[3]
5 values
2 of 3 sources agree on it (most common value).
Value As written Source
0.2 mmHg 0.2 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.
1 mmHg 1 mmHg at 158 °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.
20 mmHg 20 mmHg at 233.2 °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.
0.2 mmHgshown Vapor pressure, Pa at 20 °C: 27 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
0.18 mmHg 0.18 [mm Hg] @20 °C [5] PAC Chemical Database, U.S. Department of Energy
Flash point: 102 °C o.c.[3]
3 values
2 of 3 sources agree on it (most common value).
Value As written Source
104 °C 220 °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.
102 °C 215 °F (102 °C) (Open cup) [4] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-28
102 °Cshown 102 °C o.c. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
Autoignition temperature: 380 °C[3]
3 values
3 of 3 sources agree on it (most common value).
Value As written Source
380 °C 716 °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.
380 °C 716 °F (380 °C) [4] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-28
380 °Cshown 380 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
Viscosity: 3.23 mPa.s at 20 °C[4]
Refractive index: Index of refraction: 1.4170 at 20 C/D[4]

Value	As written	Source
–	Caproic acid appears as a white crystalline solid or colorless to light yellow solution with an unpleasant odor. Insoluble to slightly soluble in water and less dense than water. Contact may severely irritate skin, eyes and mucous membranes. May be toxic by ingestion, inhalation and skin absorption. Used to make perfumes.	[1] CAMEO Chemicals
–	Liquid; Liquid; Other Solid	[2] EPA Chemical Data Reporting (CDR)
–	OILY COLOURLESS LIQUID WITH CHARACTERISTIC ODOUR.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–shown	Oily liquid	[4] Hazardous Substances Data Bank (HSDB)cites Verschueren, K. Handbook of Environmental Data on Organic Chemicals. Volumes 1-2. 4th ed. John Wiley & Sons. New York, NY. 2001, p. 423

Value	As written	Source
−3 °C	27 °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.
−3.4 °C	-3.4 °C	[4] Hazardous Substances Data Bank (HSDB)cites Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present., p. V5: 149 (1993)
−3 °Cshown	-3 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
−3 °C	-3 °C	[5] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
202 to 203 °C	396 to 397 °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.
205.8 °Cshown	205.8 °C	[4] Hazardous Substances Data Bank (HSDB)cites Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present., p. V5: 149 (1993)
205 °C	205 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
205 °C	205 °C @760 [mm Hg]	[5] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
–	0.927 (USCG, 1999) - Less dense 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.
0.929 g/mLshown	0.929 at 20 °C/4 °C	[4] Hazardous Substances Data Bank (HSDB)cites Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present., p. V5: 149 (1993)
–	Relative density (water = 1): 0.93	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	0.9295 @25 °C	[5] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
–	5 to 10 mg/mL at 72 °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.
–	In water, 1.03X10+4 mg/L at 25 °C	[4] Hazardous Substances Data Bank (HSDB)cites Yalkowsky, S.H., He, Yan., Handbook of Aqueous Solubility Data: An Extensive Compilation of Aqueous Solubility Data for Organic Compounds Extracted from the AQUASOL dATAbASE. CRC Press LLC, Boca Raton, FL. 2003., p. 305
–shown	Solubility in water, g/100ml at 20 °C: 1.1	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
–	log Kow = 1.92	[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. 24
–shown	1.88	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
0.2 mmHg	0.2 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.
1 mmHg	1 mmHg at 158 °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.
20 mmHg	20 mmHg at 233.2 °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.
0.2 mmHgshown	Vapor pressure, Pa at 20 °C: 27	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
0.18 mmHg	0.18 [mm Hg] @20 °C	[5] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
104 °C	220 °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.
102 °C	215 °F (102 °C) (Open cup)	[4] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-28
102 °Cshown	102 °C o.c.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
380 °C	716 °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.
380 °C	716 °F (380 °C)	[4] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-28
380 °Cshown	380 °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: 0
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 0.83
H-bond donors: 1
H-bond acceptors: 1 computed here · PubChem 2
Rotatable bonds: 4
TPSA (Å²): 37.3
Formal charge: 0
XLogP3: 1.9 PubChem
Complexity: 68 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

C62.04%
H10.41%
O27.55%

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: 1.65 Crippen (Wildman and Crippen 1999)
log S (water solubility): -1.34 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 1.44 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 116.16
log P ≤ 5 (Crippen): 1.65
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: 2,136 company reports to ECHA. Source [6].

Corrosive
Acute toxicity

NFPA 704[4]

H311Toxic in contact with skin (17.1% of reports)
H318Causes serious eye damage (82.1% of reports)

Precautionary statements: P260, P262, P264, P264+P265, P270, P280, P301+P330+P331, P302+P352, P302+P361+P354, P304+P340, P305+P354+P338, P316, P317, P321, P361+P364, P363, P405, P501

View all classifications (2)

[6] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for < 0.1% (2 of 2136) of reports.
[6] European Chemicals Agency (ECHA) · 2,136 reports · DangerH311, H318

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: · 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]
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]

Storage

Separated from strong oxidants, strong bases and food and feedstuffs.[3]
Separated from strong oxidants, strong bases, food and feedstuffs.[4]

Incompatibilities

... Can react with oxidizing materials.[4]

Safety data sheets on the supplier’s page: Sigma-Aldrich, Aladdin Scientific, MolCore.

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]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]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[10]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[11]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[12]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[13]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.